Category The International Space Station

Soyuz TMA-7 was launched from Baikonur at 23:55, September 30, 2005, while ISS was over the Pacific Ocean, off the coast of Chile. McArthur and Tokarev were the Expedition-12 crew, and planned to spend 6 months on the station, while American Gregory Olsen was a paying passenger making a 10-day flight under a commercial contract with the Russians. A medical condition had grounded the American businessman from a Soyuz flight in 2004, but he returned to the pro­gramme the following year. Olsen insisted that he would be doing good work on the station and to that end he would perform a number of experiments for Russia and ESA.

The spacecraft docked to Pirs nadir at 01: 27, on October 3. Following pressure and leak checks the hatches between the two vehicles were opened at 04: 36. As with all new crews aboard the station, the newcomers were treated to the traditional Russian greeting of bread and salt upon their entry into the station. The usual safety briefing and emergency evacuation exercise followed before the new crew were allowed to settle in and Olsen’s couch liner was transferred to Soyuz TMA-6. American ISS commander Bill McArthur had arrived on ISS by Soyuz, but at that time, there was a faint possibility that he might have to stay on the station until a Shuttle could return him to Earth. During his occupation Russia’s original contract to supply Soyuz spacecraft for ISS would come to an end. If America could not find a away around the Iran Non-proliferation Act then the Russians would be under no legal obligation to return McArthur to Earth, even in the event of an emergency evacuation of the station! NASA made it clear that they expected to find a solution to the problem and negotiations were underway to overcome the problem.

A week of joint hand-over activities followed, along with the performance of a number of short-term experiments carried to the station in the new Soyuz. Mean­while, Olsen completed his 8-day experiment programme. Krikalev and Olsen even filmed a television commercial for a Japanese company while on the station. On October 4, Phillips and McArthur reviewed the software for the SSRMS, before they performed several manoeuvres with the SSRMS itself the following day. The crew also took a message from Mikhail Fradkov, the Russian Prime Minister.

Following the official hand-over and final farewells Krikalev, Phillips, and Olsen sealed themselves inside Soyuz TMA-6. Prior to undocking the crew discussed a pressure leak between the re-entry module and the orbital module with engineers in Korolev. Krikalev finally undocked the Soyuz under manual control, at 17:49, and backed it away from the station. Throughout the separation manoeuvre and de-orbit burn the pressure leak continued to cause concern until the orbital module was jettisoned, at which time it ceased. The re-entry module landed at 21:09, on target 85 km northeast of Arkalik. The Expedition-11 flight had lasted 179 days 23 minutes and Krikalev’s personal endurance record now stood at 803 days 9 hours 39 minutes. Phillips felt light-headed after being helped out of the spacecraft by the recovery forces, but could not remember afterwards if he actually blacked out. The long- duration crew were subjected to the usual 45-day medical rehabilitation. Olsen had been in flight for 9 days 21 hours 15 minutes. At a post-flight press conference he repeated his dislike of the term “space tourist’’, used by much of the media to describe commercial passengers on Soyuz taxi flights. He explained, “I dedicated 2 years of my life to this. It’s not a hop-on-and-go kind of thing.’’

Meanwhile, McArthur had described his hopes for the Expedition-12 increment before launching to the station, “Above all that we launch and land safely; that we conduct this mission in a safe manner. Having said that, I think for it to be considered a success my criteria is that we will complete meaningful science during our stay, and that we will leave the Station more capable than we found it.”

During October, the Russian government approved funding for the national space programme through 2015. It was supposed to include the joint development, with ESA, of the Kliper spacecraft and the development by Krunichev of the new Multi-purpose Science Module to be launched to the Russian sector of ISS.

In 2004, NASA had announced that it intended to stop funding ISS in 2016, as the Administration turned its attention to the Orion spacecraft, the Ares-1 launch vehicle, and the ultimate return of human astronauts to the lunar surface. Three years later, in April 2007, NASA Administrator Michael Griffin announced that ISS

was to be included in NASA’s budget requests through 2020. Griffin stated: “The partners have been working for a decade and a half to put in place these four laboratories. I don’t think political leaders in 2016 will end their involvement. Assets like the ISS live a lot longer than anticipated. I doubt it will turn into a pumpkin in 2016.’’

In mid-2007, Roscosmos announced that they had no plans to co-operate with NASA on Project Constellation until at least 2015. The Russians said that their budget had been allocated so as to allow them to support NASA’s commitment to ISS until that time, during which they would re-commence lunar exploration with robotic probes while supporting India’s and China’s robotic lunar exploration programmes. After 2015 ,Russia would be free to reconsider their position regarding Project Constellation. Meanwhile, the Russians continued to talk about building science modules for the ISS, but no new modules had been completed, as yet.

On February 26, STS-117 had been delayed by damage to the ET caused by hailstones while it stood on the launchpad. The delay caused the Shuttle’s launch programme to be rescheduled yet again:

All subsequent flights were similarly delayed.

At the same time NASA announced that they would swap the orbiters assigned to three of those flights in order to ease the pressure in the schedule:

• STS-120 would now use Discovery rather than Atlantis.

• STS-122 would use Atlantis rather than Discovery.

• STS-124 would use Discovery rather than Atlantis.

The rescheduling meant that plans to retire Atlantis in 2008 and cannibalise it to provide spare parts for Discovery and Endeavour had been changed.

NASA also announced that it had added $719 million to its contract with Roscosmos to purchase additional Soyuz TMA flights for American astronauts, to deliver and recover Expedition crews, during the period between the last Shuttle flight in 2010 and the first flight of the Orion/Ares-1 combination to ISS, currently scheduled for 2015. Despite this schedule, continual failure to make the promised annual increase to NASA’s budget to support Project Constellation made that date seem highly unlikely.

Asked previously if the Shuttle would continue to fly beyond the announced 2010 deadline set by President Bush, NASA Administrator Michael Griffin had made a one word reply, “No!” That, added to the 2007 schedule delays, meant that NASA would have to concentrate the remaining Shuttle flights on delivering the primary ISS elements into orbit before the Shuttle stopped flying in 2010. Any planned Utility flights, to support ISS operations, might yet prove to be expendable.

A thunderstorm passed over KSC on February 26, and hailstones “the size of golf balls” struck the foam exposed at the top of STS-117’s ET, leaving visible damage. They also damaged approximately 25 tiles on the orbiter’s left wing. The Shuttle stack was rolled back to the VAB for inspection and repair. and the planned March 15 launch was cancelled and rescheduled for no earlier than May 11, 2007. That date slipped back to June as NASA and contractor engineers ensured that the ET was safe to use. Shuttle programme manager Wayne Hale told journalists:

“The speculation that a lot of people have engaged in is that the last flight of the Shuttle to the space station will get pushed out of 2010. That just will not happen due to this problem.’’

He further stated:

“There might be some small effect to a couple of the later flights, but by the time we roll around to the end of the year, I expect we would be fully able to catch up.’’

The Shuttle was rolled back to LC-39A on May 15, with lift-off scheduled for June 8. On that date, Atlantis lifted off into the twilight, at 19: 38, beginning the first of four Shuttle flights planned for 2007. In the payload bay was the S-3/S-4 ITS, which would be mounted on the S-1 ITS and deployed during a series of three EVAs. The second set of SAWs on the P-6 ITS would then be retracted into its storage box, in order to allow the S-3/S-4 SAWs to rotate as they tracked the Sun.

Mission Commander Rick Sturckow had previously reviewed the work of earlier crews that had worked with the ITS elements on ISS at a prelaunch press conference, saying, “We’re really fortunate that we have those guys to follow. Almost everything went great on those missions, and the things that didn’t go so well, we’re able to learn from.’’

To overcome any repeat of the difficulties experienced on STS-115, such as when a bolt locking the SARJ in its launch position had taken much longer than planned to remove Sturckow explained:

“We have a torque multiplier… that they didn’t have. So if we do encounter the same difficulty with high torques that they had, we’ll break out this tool. And we’ll apply whatever torque it takes to break the bolt or back it out at the higher torque settings. So I don’t have any doubt that we’ll be able to remove those launch restraints.’’ He added, “When you’re doing assembly operations, everything that you plan to do is contingent on the flight prior to you and the hardware that’s already in orbit.’’

The STS-117 ascent into orbit was flawless, with no obvious signs of foam falling away from the ET in video of the launch. However, while video of the jettisoned ET showed that repairs to the hail damage had remained in place, one piece of foam, approximately 15cm x 8cm was missing. Orbital insertion was followed by the deployment of the payload bay doors and the Ku-band antenna. On ISS, Yurchikhin, Kotov, and Williams watched the launch on a video uplink from Houston.

In the latter part of the day, Forrester and Swanson activated the RMS, to test its function. As they raised the arm from its cradle they noticed that an area of insulation blanket near the port OAMS pod pulled away from the adjacent thermal tiles. Video cameras on the RMS were used to relay views of the 10 cm by 7 cm area to Houston. Similar damage had been identified on Discovery during two earlier flights and both had returned to Earth without incident. Initial reviews of the images of the blanket suggested that the airflow over the OAMS pod during the early phases of the launch had lifted the edge of the blanket and caused it to fold back on itself. Other options included: bad installation of the blanket during processing, or impact damage during launch. The Shuttle crew began their sleep period at 01: 38, June 9.

Day 2 began with a wake-up call at 10: 10 that morning. Archambault, Forrester, and Swanson activated the RMS, mounted the OBSS in the end-effector, and com­pleted the first inspection of Atlantis’ TPS. Prior to placing the OBSS back along the door hingeline, the cameras were used to view the port OAMS pod, with the detached insulation blanket. John Shannon, of the Mission Management team told a press conference, “If we decide this is a problem, we have a lot of capabilities to go address it.’’ He made it clear that Atlantis carried the equipment necessary to repair the blanket, by folding it flat and pinning it in place. While the video inspection was underway, Olivas, Reilly, and Anderson inspected the EMUs that they would use during the flight’s three EVAs. During the day the crew also extended the docking ring and installed the centreline video camera that would allow Archambault to see PMA-2 during the final approach to docking.

Following a second sleep period, June 10 began at 09 : 08. During the morning Olivas used a 400 mm lens on a digital camera to record the lifted corner of the thermal blanket on the port OAMS pod through the flight deck aft windows. The photographs had been requested during the morning briefing given to the crew by controllers in Houston. The written daily briefing was sent up to the crew and

included the reassurance that, “Although this [damage] does not appear to be a big issue, the teams are discussing several options.” On the ground John Shannon told another press conference, “It’s not a great deal of concern right now, but there is a great deal of work to be done.’’ He added further detail saying, “There’s one option on the table where we just put an astronaut out there on a spacewalk, and they just tuck the fabric right back down. There are other options where they go and try to secure it down with something.’’ A third option was to have the crew use a pressure suit repair kit to sew the blanket back into place using an instrument with a rounded end that looked like a small darning needle.

Rendezvous manoeuvres began at 10:38. Following the r-bar pitch manoeuvre at 14: 37, Sturckow moved his spacecraft in for docking with PMA-2 at 15: 36. As usual, extensive pressure checks were made to ensure the seal between the two spacecraft before the hatches were opened, at 17: 04. Williams rang the station’s bell to welcome the new crew aboard ISS at 17: 20.

Following the initial greetings and safety briefing Williams transferred her Soyuz couch liner to Atlantis, while Anderson placed his couch liner in Soyuz TMA-10. Williams had been in orbit for 183 days, longer than any other female astronaut. She would now return to Earth in Atlantis, while Anderson began a four-month occupation as part of the Expedition-15 and Expedition-16 crews.

The first task for the STS-117 crew was for Archambault and Forrester to use the RMS to lift the S-3/S-4 ITS out of Atlantis’ payload bay and hand it over to the

SSRMS, which was operated by Williams. The hand-over was completed at 20: 28, and the S-3/S-4 ITS was left on the SSRMS throughout the crew’s sleep period, allowing it to warm in the unfiltered sunlight. Reilly and Olivas spent the night camped out in Quest with the airlock’s pressure reduced to purge nitrogen from their bloodstream in advance of their first EVA, planned for the following day.

The crew were up and about at 09: 08, but Reilly and Olivas were allowed to sleep in for an extra 30 minutes. After breakfast, Archambault and Forrester used the SSRMS to move the S-3/S-4 ITS towards the exposed end of the S-l ITS and held it in place. The resulting asymmetry of the new ITS being moved around caused the CMGs in the Z-l Truss to become saturated and drop off-line and the station began to drift. This had been anticipated by controllers in Houston. Archambault, Forrester, and Kotov commanded the bolts holding the S-3/S-4 ITS in place to close. As a result of the CMG dropout, the EVA began at 16: 02, approximately one hour late. Reilly and Olivas made their way to the joint between the S-l and S-3/S-4 ITS. There, they connected power cables between the two ITS elements and released the launch restraints on the S-3/S-4 ITS SAW blanket boxes and opened them. They also released the launch restraints on the S-3/S-4 radiator, rigidised the four Alpha Joint Interface Structure struts, installed one Drive Lock Assembly, and released the launch locks on the SARJ. The EVA ended at 22: 17, after 6 hours 15 minutes. Meanwhile, controllers in Houston activated the two new power channels and deployed the new radiator. Elsewhere on ISS, Williams and Anderson continued their planned hand-over tasks.

During the evening, mission managers extended the flight by 2 days and added a possible fourth, impromptu EVA, to provide time to inspect and repair the lifted thermal blanket on the port OAMS pod. Meanwhile, engineers and astronauts on the ground were trying to establish the best way to make the repair. In the regular end-of – shift press conference at MCC-Houston, Shannon informed the press and media, “We do not want to re-enter until we have done this. I don’t want to take a risk of damaging flight hardware, when we have something that looks easy to do, so it’s a pretty easy decision to make.’’ On the ground, the various repair methods were being rehearsed and subjected to testing under simulated re-entry conditions. Shannon explained that Shuttle engineers did not think that the re-entry heating on the OAMS pod would be sufficient to burn through the graphite structure beneath the lifted blanket, causing an STS-107 style break-up, but it might cause sufficient damage to require a relatively major repair, thereby throwing the Shuttle launch schedule into total disarray. The 90-minute repair would be carried out by two astronauts riding the Shuttle’s RMS. Atlantis would now land on June 21, after a 13-day flight. In orbit the day had gone well, and the crew began their sleep period. Learning from past experience, Houston commanded the new SAWs to extend in a series of small lengths. The first segment was deployed by controllers in Houston while the astronauts slept.

On June 12, the astronauts’ day began at 08: 08. At 11: 43, Sturckow, Arch – ambault, Forrester, Swanson, Olivas, Reilly, and Williams took over the task of deploying the S-3/S-4 SAWs and observing that deployment from inside ISS and Shuttle. Each SAW was deployed separately and in small stages, with regular stops to let the Sun warm the array. The first SAW was fully deployed by 12: 29, and the second by 13:58. Reilly told Houston, “We see a good deploy.” The new arrays would provide sufficient electricity to power the European and Japanese laboratory modules when they are docked to Harmony.

After dinner the Shuttle crew were given some free time before commencing preparations for the following day’s EVA. Throughout the SAW deployment, the station’s attitude had been controlled by Atlantis. As the day drew to a close, the station’s attitude control was switched back to the station’s computers. At that time all three navigation computers and all three command and control computers failed in Zvezda. The computers were built by Daimler-Benz in Germany, under an ESA contract, and one of their tasks was to activate Zvezda’s thrusters if ISS attitude manoeuvres were beyond the capabilities of the CMG. Controllers elected to let the CMGs continue to manage the station’s attitude, but Atlantis’ thrusters would be used for large manoeuvres, rather than Zvezda’s thrusters. The day ended with the pre-positioning of the MBS on the ITS and that night Forrester and Swanson camped out in Quest; both were preparations for the EVA planned for the following day. While the astronauts slept, controllers in Houston began the retraction of the remaining SAW on the P-6 ITS. They succeeded in retracting 7.5 of the 31.5 panels of the array.

The day started at the usual time and the EVA began at 14:03. Forrester mounted the RMS end-effector and was lifted to the P-6 ITS, mounted on the Z-1 Truss, while Swanson made his own way to the location. Once in place, they oversaw and assisted with the retraction of a further 5.5 panels of the 2B SAW, as commanded from inside the station. Moving back to the S-3/S-4 ITS, they removed the remaining locks holding the SARJ. Although they had originally been planned to remove the launch restraints, they left them for the third EVA. When the restraints were finally removed the joint would be free to rotate, as the SAWs tracked the Sun. They also installed a second drive-lock assembly. and that was where their problems arose. Commands sent to the second drive-lock assembly were received by the unit installed during the first EVA. Controllers in Houston confirmed that the first unit was in the “safe” condition and had to confirm that the second unit was similarly configured. The SAW retraction would continue during the following day. The EVA ended at 20: 33, after 7 hours 16 minutes. Once again Anderson spent the day completing hand-over tasks in preparation for his 5-month stay on ISS, as well as assisting Expedition-15 crewmates Yurchikhin and Kotov to transfer supplies from Atlantis to ISS. During the day mission managers confirmed that at least part of the third EVA would be spent repairing the port OAMS pod thermal blanket.

On June 14, Houston awoke the crew officially at 08: 39. In fact, they had been woken up at 07: 23, when a fire alarm sounded in Zarya. It was a false alarm set off by the loss of three Russian command and control computers, affecting the life support system and causing power outages throughout the Russian sector of the station. During the day controllers in Korolev temporarily rebooted the navigation computer and then turned it off again to continue work on the original problem. By 11 : 38, Sturckow, Lee, Archambault, Swanson, Williams, and Anderson resumed the attempt to retract the P-6 SAW. Meanwhile, Forrester, Reilly, and Olivas reviewed the procedures for their third EVA. The three of them practised the plan to staple the

two sections of thermal blanket on Atlantis together and pin it to an adjacent thermal tile. Sturckow told Houston, “When we first saw it, we were not too concerned. We’re still not. This is just the right thing to do, the conservative thing to do. We appreciate everyone taking a look to make sure we have the right configuration for re-entry.’’

In Moscow, Russian engineers continued to work with their American counter­parts on the computer problem throughout the day. The leading theory as to the cause of the computer problem was a bad electrical power feed between the American and Russian sectors of ISS, as the computers now drew their power from the ITS. NASA’s Mike Suffredini explained, “A power line has a certain magnetic field around it, and that can affect systems near it.’’ Plans included disconnecting power cables between the two sectors of the station, rebooting the computers, and then reconnecting the power cables. If the problem recurred, the computers in the Russian sector could receive electrical power from the photovoltaic arrays on the Russian modules. Sturckow was objective, “These challenges, they come up when you bring new pieces of hardware or when computers are improved. This is to be expected. Things aren’t always going to go well.’’ Meanwhile, NASA Associate Administrator for space operations Bill Gerstenmaier was positive, telling a press conference, “This is a complex station. This failure is not easy to understand. It’s some combination between Russian systems and our systems. It’s just going to take a little bit of time to get this worked out.’’ He added, “We’re still a long way from where we would have to de-man the station.’’

NASA was at pains to point out that the station had 2 months of oxygen supply if the Russian oxygen generator could not be brought to full operation. Also the American oxygen system was nearly completely installed. Carbon dioxide removal systems were also available in both the Russian and American sectors. In Russia, the difficulties led to discussions as to whether or not to advance the next Progress launch by two weeks, to July 23, and use that launch to deliver new computer parts to the station.

Before going to bed, Williams and Anderson checked power lines and circuits connected to the new S-3/S-4 ITS that supply electricity to the Russian modules with a number of diagnostic instruments, but found nothing that could account for the computer difficulties. Meanwhile, the STS-117 crew had been instructed to power down some of Atlantis’ systems, just in case the Shuttle mission needed to be extended by a further day, to continue supplying back-up attitude control. A NASA spokesman told the press, “I expect we will have the computers back in the next several days. It’s not an urgent situation, but we clearly need to get this resolved.’’ Asked if the station would be evacuated if the computer problem persisted NASA’s Mike Suffredini insisted, “The best thing we can do is keep the crew onboard to keep working this problem until we sort it out. That is what our plan is.’’ Meanwhile, John Shannon confirmed that Atlantis would remain docked to ISS until June 20. Reilly and Olivas spent the night camped out in Quest breathing oxygen at a lowered pressure in preparation for the crew’s third EVA.

As the new day started Russian controllers disconnected the Russian modules from the new electrical power supply, returning them to the supply provided by their own photovoltaic arrays. The STS-117 crew’s wake-up call came at 08: 41, June 15,

Reilly and Olivas began preparations for their EVA straight after breakfast. The EVA began at 13:38. After collecting their tools they prepared to repair Atlantis’ thermal blanket. Olivas mounted the Shuttle’s RMS and was manoeuvred to the port OAMS pod, where he pushed the folded thermal blanket back into the correct position. Using a stapler from the Shuttle’s medical kit he fixed the offending blanket to the blanket next to it. Finally, he drove a metal pin through the blanket, securing it to the adjacent thermal tiles. The repair took the full 2 hours that had been allocated for it. As he completed the task Olivas told controllers in Houston, “Hopefully it’s going to be good, good enough.’’ Sturckow, the Shuttle’s Commander added, “He’s done an absolutely wonderful job.’’

While Olivas repaired the thermal blanket, Reilly installed a hydrogen vent in the forward face of Destiny. The vent would be used by the new American oxygen generation system. The new system would separate water into oxygen as the Russian Elektron oxygen generator did, for the crew’s life support system, and hydrogen which would be vented overboard through the new vent. With the repair and the valve installation complete, both men moved to the P-6 ITS, where they assisted in the retraction of the last 15 bays of the 2B SAW. While the retraction was com­manded from inside the station, the two EVA astronauts assisted by helping to fold the SAW and ensuring that they were correctly stored in the blanket box. Finally, they secured the lid of the blanket box itself. The retraction was completed at 20:40. The EVA ended at 21: 36, after 7 hours 58 minutes.

While the Americans concentrated on their EVA, the Russians continued to work on the failed computers. All of the computers were taken off-line at 06: 00 and left off-line throughout the day. Yurchikhin and Kotov used a jumper cable to bypass a power switch, thus allowing them to get both C&C computers partially running. It was decided that the one processor in each computer that did not re-boot would be replaced using spares to be delivered by the next Progress. The computers, which only required one processor each to perform their role on ISS, were left running overnight. A telemetry downlink over a Russian ground station allowed controllers in Korolev to monitor the computers’ performance over the test period. NASA spokeswoman Lynette Madison told the press, “They’re up and operational and this is good news for all.’’ Mike Suffredini made a similar comment, “We feel like the computers are stable and back to normal.’’

Whilst the two crews were asleep, Sunita Williams became the most experienced female astronaut in history. At 01: 47, June 16, she passed the female endurance record of 188 days 4 hours set by her NASA colleague, Shannon Lucid. Later in the day Williams remarked:

“I feel like a lot of this was just sort of being in the right place at the right time. It just sort of happened. It’s just an honour to be up here. Even when the station has little problems, it’s just a beautiful, wonderful place to live. I’m just happy to be part of history that provides a steppingstone for the next generation of explorers and women to come up here and do that. To me, it’s no big deal.’’

Williams admitted:

“My biggest desire is to go for a walk on the beach. I grew up near the beach in New England, and I love going to the beach.”

Lucid, who had worked in MCC-Houston during Williams’ flight, told a press conference, “She’s done an absolutely wonderful job. I think it’s really great because it shows the space programme is getting more mature when you have more and more people stay in space for longer periods of time.’’ She added, “I said [to Williams], ‘Enjoy your last few days because all too soon you will be back to bills, dirty dishes and laundry’.’’

The Shuttle crew’s wake-up call came at 08:38, June 16. They spent the day transferring supplies from Atlantis to ISS and preparing for the flight’s fourth EVA. Yurchikhin and Kotov used a second external cable to redirect the power supply, allowing them to bring the final two computer processors on-line. With Zvezda’s computers performing well, controllers in Korolev began assigning them some of their usual control tasks. The computers were now talking to the equivalent C&C computers in the American sector of ISS, something they had not been doing for the past 3 days. By this time most people did not believe the S-3/S-4 power supply had caused the computer problem. Flight Director Holly Ridings stated, ‘‘In the last 24 hours, we’ve had a lot of successes.’’ ISS programme manager Mike Suffredini, summed up his feelings succinctly, ‘‘Spaceflight is a challenging business and these are the things you occasionally have to deal with. We can all go home and not do it, or we can choose to explore. We choose to explore.’’ He told the media, ‘‘We’re having a great day on orbit.’’ As the day continued NASA suggested that Atlantis would land on June 21. On hearing the news, Sturckow replied, ‘‘That’s great news.’’

June 17 began at 07: 38. Following breakfast everyone began preparations for the final EVA. Forrester and Swanson had spent the night camping out in Quest. Their EMUs were transferred to internal battery power, commencing the EVA at 12: 25. Kotov shadowed Reilly as intravehicular crew member, in preparation for his assum­ing that role during an up-coming Expedition-15 Stage EVA. Having collected their tools, Forrester and Swanson set to work. Their first task was to retrieve a camera and its stand from a mounting on the exterior of Quest and move it to the S-3 ITS. While on the S-3/S-4 ITS, they confirmed the Drive Lock Assembly-2 configuration and then removed the final six SARJ launch restraints, leaving the SAWs free to rotate and track the Sun as ISS orbited Earth. Reilly told them, ‘‘Great job, Guys,’’ Swanson replied, ‘‘That’s what we came here to do.’’

Still on the ITS, they moved the temporary stops installed on the MBS rails, leaving the MBS free to travel along its rails on the new length of ITS. They also removed additional equipment that had held the S-3/S-4 ITS in the Shuttle’s payload bay. The task was the final one scheduled for STS-117 and was completed by 16: 17. The remaining activities were ‘‘get-ahead’’ tasks. First they installed a computer network cable on the outside of Unity and then moved to open the newly installed hydrogen vent valve on Destiny. Finally, they tethered two debris shield panels on Zvezda. The EVA ended at 18: 54, after 6 hours 29 minutes. Inside, the Russian computers had been returned to controlling the station’s systems, and even the

Elektron oxygen generator was powered on, but not configured to produce oxygen. The computers remained stable.

During an evening press conference, Anderson was asked how he was adapting to life on ISS. He replied, “I think I’m hanging in there. It kind of reminds me of my first swimming lesson. I just got tossed in the water and told to survive.’’ Questioned on the subject of Zvezda’s computers, Yurchikhin remarked cautiously, “We’re slowly moving back toward a normal mode of operations.’’

While the two crews slept, American controllers in Houston activated the SARJ on the S-3/S-4 ITS and tested its rotation. At 20:00, the SARJ was placed in auto­track mode. The ISS now had a new symmetrical shape, with a pair of SAWs at either end of the ITS and the P-6 SAWs fully retracted, although the P-6 ITS was still attached to the Z-l Truss, with one of its huge radiators still deployed.

The final day of docked Shuttle operations began with the crew rising early, at 07: 08, June 18. The crew of Atlantis had the morning off after the hectic pace of the past few days. They completed the final transfer of equipment to Atlantis during the afternoon. At 10: 28, the Shuttle’s thrusters were used to manoeuvre the station into the correct position for a combined potable water and waste water dump and then manoeuvre it back to the original position. Once the combination was stable, after the second Shuttle manoeuvre, at 10: 34, attitude control was passed to the Russian terminal computer. The computer activated the thrusters on the Russian modules to maintain the station’s attitude. At 12: 09, attitude control was handed back to the American computers and the CMGs mounted in the Z-l Truss. The test was summed up by NASA’s Phil Engelhauf, “There was absolutely nothing anomalous out of the testing. Everything performed exactly as it should have.’’ Only after the test of the Russian computers was successfully completed did NASA managers confirm that Atlantis would undock at 10: 42, June 20.

After saying their goodbyes to the Expedition-15 crew, Sturckow led his crew back to Atlantis, securing the hatches between the two vehicles for the final time at 18: 51. Sunita Williams was included in that crew, returning to Earth after almost 6 months in space. Williams remarked, “It’s sad to say goodbye, but it means that progress is being made.’’ Yurchikhin told controllers, “We had a really great time with Suni up here.’’ Her place on the Expedition-15 crew had been taken by Clayton Anderson who remarked, “I hope I can carry on, and do half as well as she did.’’

Atlantis undocked at 10: 42, June 20, with Archambault at the controls. The Pilot manoeuvred the orbiter around the station so that the crew could complete a photographic and video survey, before performing the separation manoeuvre. Sturckow told the Expedition-15 crew, “Have a great rest of your mission.’’ Yurchikhin replied, “Godspeed, and thanks for everything.’’

Following the separation burn, the crew used the RMS-mounted OBSS to carry out further scans of the Shuttle’s nosecap and wing leading edges. The images were down-linked to Houston before the astronauts began their evening meal and sleep period. Following an early morning start, the crew spent what should have been their last full day in space carrying out all of the routine preparations for re-entry. These included a test of the aerodynamic surface and a test-firing of each of the Shuttle’s manoeuvring thrusters. While the crew prepared to come home, the weather over

Florida threatened the plans for returning to that location. Sturckow told controllers in Houston, “Get us some good weather for Thursday, if you can. It doesn’t have to be good, just good enough.’’

On June 21, the final preparations were made. Following breakfast the Ku-band antenna was stowed, and the payload bay doors were closed at 10:05. Retrofire was planned for 12: 50. That attempt was cancelled due to bad weather. The day’s final landing opportunity demanded retrofire be completed at 14: 25, but that attempt was cancelled at 13:38, as the weather in Florida showed no signs of clearing. Sturckow was informed, “The rain showers and cloud ceilings will keep us from making it into Florida today. We are going to try again tomorrow.’’

Atlantis’ payload bay doors were re-opened and a manoeuvre was performed to adjust the orbit to support the five available landing attempts (two at KSC in Florida and three at Edwards Air Force Base in California) on June 22. The crew spent the extra day and night in orbit, before beginning re-entry preparations again.

On June 22, Sturckow was informed, “Our mindset is we’re going to land you somewhere safely today.’’ The payload bay doors were closed at 09: 32. The first attempt to land in Florida was cancelled. Landing finally occurred on the dry lakebed at Edwards Air Force Base, California, at 16: 49. The flight of STS-117 had lasted 13 days 20 hours 11 minutes. Williams had been in space for 195 days. At the post­landing press conference NASA Associate Administrator for space operations Bill Gerstenmaier told the media, “My hat’s off to the team that really pulled off an awesome mission.’’ Returning Atlantis to Florida on the back of a Boeing 747, NASA carrier aircraft would require a week’s work and cost $900,000.

In the weeks following Atlantis’ recovery, pressure suit engineers discovered a small cut in the outside layer of one of Curbeam’s EMU gloves. As a result, NASA introduced a new rule that required astronauts on an EVA to examine their gloves approximately every 60 minutes while they were in a vacuum.

After the standard weekend of light work McArthur and Tokarev began working full time on their experiment programme, as well as commencing their housekeeping, maintenance, and daily exercise regimes. They reviewed procedures for an emergency escape from the station, changed a battery in Zvezda, and rearranged the items stowed inside Unity. McArthur began work with the Pulmonary Function Facility in Destiny. Both men also began the first of a series of Renal Stone Experiment food logs and gave urine samples for the same experiment. By the second week of October the new crew were beginning preparations for their first Stage EVA, which would be made from Quest and would be the first to use American EMUs since 2003. The 5.5-hour EVA was planned for November 7. The Elektron oxygen generator in Zvezda shut down unexpectedly on October 13. The problem was a result of a partially filled source water tank being connected to the system, rather than a full tank.

Progress M-54’s engines were to be used to boost the station’s orbit on October 18. The engines began thrusting at the correct time but the procedure was aborted when a Russian navigation computer lost telemetry and shut them down. Trouble­shooting began at Korolev. On October 17 and 21 the station’s atmosphere was repressurised using oxygen from Progress M-55. Meanwhile, planning was underway at Korolev for another attempt to repair the Elektron unit. Tokarev purged the air bubbles from the Elektron oxygen generator’s systems during a 5-hour work session on October 22, thereby restoring the unit to use. During the same week, McArthur checked out the second Pulmonary Function Facility, developed by ESA for use inside their Columbus laboratory module and carried to ISS on STS-114, the unit had been installed in HRF-2 in Destiny.

On October 25, the two men carried out routine tests of the two EMUs that they would wear during their first EVA. The following day they reviewed the procedures for donning and operating the EMUs. On October 27, they donned the suits and rehearsed their EVA activities inside the station. Meanwhile, on October 26, Russian controllers had performed a test-firing of Progress M-55’s engines, using a different manifold to that used during the aborted re-boost firing. The engines operated normally and there was no loss of telemetry. Tokarev celebrated his birthday on October 29. The following day, both men worked to strip down and sample the airflow in the Trace Contaminant Control System. Engineers had noticed a reduction in the airflow and the astronauts’ work led to the conclusion that replacement parts might be required. Following re-assembly, the unit continued to work at a reduced

airflow rate. During the week they also replaced a faulty pump in a thermal control loop in Zvezda, and replaced smoke detectors, also in Zvezda.

McArthur and Tokarev marked the fifth anniversary of permanent human presence on ISS on November 2, 2005. They sent messages to everyone who had flown to the station and to the engineers and scientists from 16 nations who supported its activities.

At 10:32, November 7, McArthur and Tokarev began their first EVA as they placed their EMUs on to battery power and began depressurising Quest. During the preparations they had to repressurise the airlock and re-enter the inner chamber of the two-chamber module and reset a misaligned valve. They then had to seal them­selves back in the outer chamber and depressurise it for a second time. Exiting the airlock, they collected their tools and retrieved a stanchion for a television camera from a toolbox mounted on the exterior of Quest, before making their way to the outer limit of the Port-1 ITS, where they installed a television camera on a stanchion and installed this on the outer limit of the Port-1 ITS. When power was applied to the camera the first pictures were received just before 13: 00. The new camera would be used during future assembly tasks, when additional SAWs would be added to the port side of the ITS. The camera should have been installed as part of the final STS-114 EVA, but the installation was delayed to allow for the removal of the two gap fillers from the underside of the orbiter. Their next job was a “get-ahead” task. They removed a failed Rotary Joint Motor Controller (RJMC), a box of electronics. It had not yet been used, and was to be returned to Earth on the next Shuttle for evaluation of why it had failed.

Both men then used their hands to make their way to the top of the P-6 Truss, the “highest” point on the station. There, McArthur removed the now defunct Floating Potential Probe and pushed it away from the station. It would burn up when it re­entered Earth’s atmosphere, in approximately 100 days. It had been installed by the STS-97 crew in December 2000, to help define the electrical environment around the station’s SAWs. Images taken on STS-114 had shown it to be breaking up, so the decision was taken to remove it. With both of their primary tasks completed, the crew received permission to progress on to a second “get ahead’’ task. They removed a failed circuit breaker controlling redundant heating on the Mobile Transporter, and installed a new one. The two astronauts then returned to Quest after an EVA lasting 5 hours 22 minutes. In the days following the EVA both men spent time servicing the suits they had worn.

On November 10, Progress M-54’s thrusters were fired to boost the station’s orbit. The 33-minute, two-stage re-boost was the longest yet carried out using the engines of a Progress spacecraft, and was designed to place the station in the correct orbit for the arrival of Progress M-55, in December. During the week the station toilet control panel malfunctioned and Tokarev replaced it. The following week, McArthur spent several hours photographing the Binary Colloidal Alloy Test experiment that had been undisturbed in microgravity for over a year.

After configuring the station for automatic function the crew sealed themselves inside Soyuz TMA-7 on November 18. At 03: 46, Tokarev undocked the Soyuz from Pirs and manoeuvred along the station to dock at Zarya’s nadir, at 04: 05. McArthur and Tokarev returned to ISS just after 10:00. The newly installed Port-1 ITS television camera transmitted images of the manoeuvre, which cleared Pirs’ nadir for the crew’s second Stage EVA, during which they would wear Orlan suits. The EVA was originally planned for December 7, but was under review as the crew moved their spacecraft. Mission managers were considering delaying the EVA to early 2006, in order to give the crew more time to unload Progress M-54 and prepare it for undocking.

McArthur powered up the SSRMS on November 21, and put it through a series of engineering tests. He left it in a suitable position for its cameras to monitor the crew’s second EVA, which had been rescheduled to February 2, 2006 by that time. A possible third Stage EVA was cancelled, because the “get ahead’’ tasks had been achieved during their first EVA, in November. November 24 was a day off for the crew to celebrate the American Thanksgiving Holiday.

During the week ending December 2, McArthur worked with the HRF-2 experiment rack in Destiny. He set up a refrigerated centrifuge and worked with the BCAT-3 and InSPACE Magnetic Materials experiments. He also replaced fuses in a Trace Contaminant Monitor in Destiny. At the same time Tokarev used oxygen contained in Progress M-54 to repressurise the station. Propellant was also trans­ferred from Progress to Zarya. Tokarev also installed a muffled adjustable fan in the crew quarters to reduce noise in that region. Both men spent time collecting rubbish for disposal in Progress M-54. Oxygen from the spacecraft was pumped into the station’s atmosphere and the 221 kg of propellant that it carried was transferred to Zvezda’s tanks. McArthur replaced an air circulation fan in one of Destiny’s experiment racks and updated the software used by all five experiment racks in the laboratory module. Tokarov repaired air ducts in the American sector, thereby improving airflow in the modules. He also installed muffled fans in the sleeping quarters, thereby reducing the noise that the fans in that important area produced. As part of the preparation for Progress M-54’s undocking they removed the space­craft’s Kurs automatic docking system for return to Earth. Ultimately, plans to undock Progress M-54 on December 20 were cancelled in favour of keeping the craft docked to the station for several more months, thereby allowing the crew to continue to use its oxygen supply and to load it with additional rubbish. The second week of December was taken up with biomedical experiments and maintenance work. On December 16, one of two cables carrying power, command data, and video to and from the Mobile Transporter was severed, causing loss of data. Telemetry suggested that the cable had been deliberately cut by the disconnect actuator system, designed to cut the cable if it became snagged or tangled. This was a malfunction of the cutting system. The cable being severed resulted in one of two redundant electrical power circuit breakers being tripped. The second cable, on the other side of the ITS, remained undamaged.

As the year drew to a close, ESA announced that technical difficulties had led to the first Ariane-V/ATV flight being delayed by almost a whole year, to 2007. ESA had also transferred the launch of the European Robotic Arm from the American Shuttle to a Russian Proton launch vehicle. A third ESA announcement gave details of how the organisation had refused the requested $51 million to undertake a joint

Preparatory Design Study with Roscosmos of Russia’s proposed Kliper spacecraft. The vote went against the proposal because ESA would have no control over the programme and would receive only minor industrial contracts. NASA also had an announcement: with the redirection of the American human spaceflight programme towards the new Project Constellation, the Administration had already begun cancelling some experiment projects designed to be flown to ISS. On the positive side, Congress had approved the purchase of additional access to Russian Soyuz spacecraft, despite the wording of the Iran Non-proliferation Act. The new spacecraft would provide access to ISS and CRV responsibilities for American astronauts through 2012. It was accepted that some of the “taxi” flights would carry spaceflight participants in the third couch. At the same time, Russia agreed to double the production rate of Soyuz spacecraft from 2009, thereby allowing the ISS Expedition crew to be made up to six people, supported by two Soyuz CRVs docked to the station at all times. Seven Soyuz spacecraft would be flown in the period 2008-2011. Eight Progress spacecraft would fly in the same period.

Even as STS-117 continued the construction of ISS, NASA was thinking about its end. Under the original plan for the present ISS configuration, as defined in the Memorandum of Agreement signed by all ISS partners, the station was intended to be operational until 2016, at which time it would be de-orbited in such a way that any items that survived re-entry would fall harmlessly into the Pacific Ocean. To achieve that end, NASA had originally planned to dock a Shuttle to the station and use its thrusters to fire the de-orbit burn. As the operational portion of the programme was continually delayed the possibility of operating ISS beyond 2016 came under discus­sion, but the 2016 end date remained as a NASA budget planning tool. Recently, NASA had been openly talking of funding and operating ISS beyond 2016 (which had always been a distinct possibility), but now the Shuttle was due to stop flying in 2010, so it would no longer be available to de-orbit the ISS at the end of its operational life.

In mid-2007, one possibility that NASA was considering to replace the Shuttle in the vital ISS de-orbiting role was the ESA ATV. In the plan NASA would purchase an ATV and its Ariane-V launch vehicle from ESA. When the final flight was required ESA would launch the ATV for NASA and fly it to a docking with Zvezda’s wake. The ATV’s thrusters would then be used to perform the de-orbit burn, bringing ISS down as planned, with any surviving debris falling in the Pacific Ocean.

ESA’s original contract was for six ATVs, but only five ATV launches were currently shown on the ISS launch manifest up to 2016. If the sixth vehicle was not built, ESA would suffer financial penalties. The NASA de-orbit plan, which offered a possible customer for the sixth ATV, was raised during discussions between NASA and ESA regarding ATV launch schedules which had been subject to numerous delays.

As the negotiations continued, the first ATV launch was due in January 2008. Jules Verne, the first ATV, was undergoing pre-flight review in Noordwijk, Holland, to clear it for shipping to the Ariane-V launch site in Kourou, French Guiana.

One major problem with the ATV de-orbit plan lay in the fact that NASA was now budgeting for America’s continued use of ISS, using the proposed Orion spacecraft, through 2020. ESA could not promise to fund the ATV and Ariane-V programmes, with their associated infrastructure through 2020, if the fifth and final ATV cargo delivery flight was scheduled for 2016. Meanwhile, ESA was reviewing the computers to be used on the ATV, which were the same as those that ESA had supplied for Zvezda.

Progress M-55 was launched from Baikonur, at 13:38, December 20, 2005 with 2,490 kg of cargo. The new spacecraft carried food, including 14 kg of fresh fruit and vegetables, water, oxygen, propellant, spare parts, and experiments for ISS. Progress docked to Pirs’ nadir automatically at 14:46, December 23. The crew began unloading the dry goods over the holiday week.

In the week running up to Christmas, McArthur and Tokarev performed experi­ments and recorded educational films. McArthur checked the hatch seals in the American modules of the station. The Christmas break represented the halfway point in their 6-month mission. On Christmas Day they were able to speak to their families, ate a traditional Russian meal, and opened the gifts that had been delivered on Progress M-55. They had a day off on December 26, and again on January 2, in keeping with standard American government employment rules that gave employees a day off in lieu when a national holiday falls on a Sunday. Meanwhile, Zvezda’s Elektron oxygen generator had been performing flawlessly since its last repair. It was deliberately shut down between December 28 and February 9, to allow the crew to burn Russian SFOG oxygen candles in order to re-certify that method of producing oxygen. On December 31, the last of the oxygen carried in Progress M-54 was used to re-supply ISS.

McArthur and Tokarev spent the first week of 2006 performing experiments, including the ground-commanded BCAT-3, placing the “phantom Torso’’ with its 370 radiation detectors in Pirs, and locating the EarthKam in one of the station’s windows in advance of the new school term. They also installed batteries in the American EMUs in Quest. January 9 was the final day of the Russian holiday and the crew had the day off. During the week, they installed the Recharge Oxygen Orifice Bypass Assembly (ROOBA), a method of allowing EVA astronauts to pre­breathe oxygen from the Shuttle’s supply rather than the station’s tanks in Quest. Two days later the Elektron oxygen generator was powered on. On January 12, McArthur manoeuvred the SSRMS to provide views of the Interface Umbilical Assembly (IUA) on the S-0 ITS, which held the cable cutter for the MT’s uncut power cable. The following day he manoeuvred the SSRMS to view the CBM at Unity’s nadir and ensure that it was clear of debris. The SSRMS was left in a position where its cameras could view the crew’s up-coming EVA.

On the ground, the Houston marathon was taking place on January 15. In orbit, McArthur ran a half-marathon on the treadmill while ISS circled Earth. Over January 17-18, they rehearsed the procedures to be followed in the event of a rapid pressure leak requiring evacuation of the module in question. The following day, programme managers delayed the next EVA from February 2 to February 3, in order to ease the astronauts’ preparation schedule. The remainder of the week was taken up with both men performing experiments for their national programmes.

In the week commencing January 23, both men began preparing for their EVA. On January 31 they prepared an old Orlan suit, mounting a radio and slow-scan television transmitter on the helmet. The system transmitted messages in six lan­guages that could be received by amateur radio operators. Now called “RadioScaf”, the suit had last been worn by Michael Foale in February 2004. It was filled with rubbish and would be jettisoned from ISS during the EVA. After preparing ISS for automated flight regime and shutting down the Elektron generator, the oxygen delivered in Progress M-55 was used to pressurise the ISS.

McArthur and Tokarev left Pirs wearing Orlan suits at 17:44, February 3. Having prepared their tools, they removed RadioScaf from the airlock and mounted it on a ladder on the exterior of the module, before releasing the suit into orbit with the words, “Goodbye, Mr. Smith,” from Tokarov. They photographed the suit as it drifted away. It transmitted its greeting messages for two orbits before the transmitter stopped working.

Moving away from Pirs, the two men made their way to the exterior of Zarya, where they removed a grapple fixture adapter for the Russian Strela crane and moved it to PMA-3, mounted on Unity. The adapter was removed to prepare Zarya for the temporary stowage of debris shields, prior to their deployment on a later Shuttle flight. Command of the EVA passed from Korolev to Houston as the astronauts passed from the exterior of Zarya on to the exterior of Unity. Next, they moved to the S-0 ITS, where they attempted to drive home a safety bolt in the cutting device in the IUA that McArthur had filmed on January 13. Despite several attempts with a high – tech tool, the safety bolt could not be installed to prevent the blade from falling and cutting the cable. Instead, as a temporary measure, McArthur removed the cable from the cutting mechanism and tied it to a handrail with a piece of wire. The cut cable on the other side of the ITS would be repaired during an EVA by the crew of STS-121. After transferring control of the EVA back to Korolev, the final task for this EVA was to photograph the exterior of Zvezda before returning to Pirs, where Tokarev recovered the Biorisk-2 experiment. The airlock hatch was closed after an EVA lasting 5 hours 43 minutes.

Two days later NASA Administrator Michael Griffin made a speech from NASA Headquarters, Washington, in which he stated:

The greatest management challenge the agency faces over the next five years is the transition from retiring the Shuttle to bringing the Crew Exploration Vehicle on-line… We are delving more deeply into the strategic implications of using Shuttle-derived launch systems for the Crew Launch Vehicle and Heavy – Lift Launch Vehicle… Thus, we are applying some funds from the exploration budget profile between now and 2010 to the Shuttle’s budget line to ensure the Shuttle and Station programmes have the resources necessary to carry out the first steps of the Vision for Space Exploration. NASA has asked industry for proposals to bring the CEV on-line as close to 2010 as possible, and not later than 2012 …’’

Griffin had initiated studies inside NASA to replace the Delta-IV and Atlas-V launch vehicles proposed for the CEV with a launch vehicle derived from proven Shuttle technology. Those studies would lead to the new Ares class of launch vehicles.

In the days following the EVA the crew took part in the standard debriefings with experts on the ground. McArthur also conducted a video tour of the station. The crew also continued their experiments; McArthur participated in the LOOT experiment, and Tokarev performed two ESA experiments. Both men performed Russian biomedical experiments and monitored the numerous experiments that ran automatically. They also gave the treadmill its 6-monthly overhaul. The motors in Progress M-55 were used to boost the station’s orbit on Lebruary 11. This was the first time that a Progress docked to Pirs had been used for an orbital re-boost. Over Lebruary 16-17, McArthur worked to replace the spectrometer inside the Mass Constituent Analyser (MCA) in Destiny. This measured the composition of the station’s internal atmosphere. An attempt to power the device up on the second day failed and McArthur was requested to perform troubleshooting.

As a new week began plans for the crew to “camp out’’ in Quest for their Lebruary 23-24 sleep period were delayed until March. The experiment called for the two men to spend a single sleep period in the airlock with the hatches sealed and the pressure reduced. Although they would not be wearing their EVA suits, the camp – out was seen as a way of reducing the pre-breathing of pure oxygen required before an extravehicular activity, by having future EVA astronauts spend their sleep period prior to an EVA camping out in Quest, and remaining in the airlock when they wake up, in order to don their EMUs and prepare for the EVA. The camp-out procedure would be used for the first time by EVA astronauts on STS-115. The delay was called as a direct result of McArthur’s failure to repair the MCA and, pending its repair, the camp-out was rescheduled for March 23.

McArthur and Tokarev began preparations for the next Shuttle flight, STS-121, now planned for no earlier than July 2006. McArthur made space in Destiny’s experiment racks for the equipment that Discovery would deliver to ISS. Both men worked to load Progress M-54 with additional rubbish, in preparation for its undocking planned for March 3. Meanwhile, on Lebruary 21, Progress M-55 per­formed a second re-boost manoeuvre. Progress M-54 was finally undocked from

Zvezda’s wake at 06:06, March 3, 2006. Three hours later controllers in Korolev commanded it to re-enter the atmosphere, where it burned up over the Pacific Ocean. With the Progress gone, McArthur returned to his work on the MCA.

Meanwhile, on March 2, the programme managers from all of the ISS nations agreed a revised launch schedule to bring the station to “Core Complete’’, plus the International Partner modules before the Shuttle was grounded in 2010. The new schedule required 16 Shuttle flights, but almost as many Shuttle flights were wiped off the launch manifest. A number of Utility flights were removed, as were Russian plans to launch a smaller than originally planned MEM. The Americans would now supply additional electrical power to the Russian sector from the SAWs on the ITS, through 2015. The European and Japanese experiment modules were advanced, now launch­ing in late 2007 and early 2008. Russian, European, and Japanese robotic cargo vehicles would now deliver many of the items originally scheduled to be launched on the cancelled Shuttle flights. NASA administrator Michael Griffin told reporters at KSC:

“The main thing you are seeing here today is the decision to put together an

assembly sequence that allows us to have very high confidence we will finish the

space station by the time the Shuttle must be retired… It’s the same station.

The end product is very much as we envisioned it.’’

McArthur completed proficiency training on the SSRMS on March 8. Over the next two days Controllers in Houston moved the SSRMS to view the IUA that had malfunctioned in December, cutting the back-up cable to the MT. They also viewed a valve on Destiny, looking for contamination. The valve was used to vent carbon dioxide overboard and appeared to be clean. This was the first time the SSRMS had been operated from the ground in an operational, rather than an experimental capacity.

The decision to retain Progress M-54 meant that Progress M-55 had had to dock to Pirs. The crew now had to move Soyuz TMA-7 back to Zvezda’s wake, thus allowing the Expedition-13 crew to dock Soyuz TMA-8 at Zarya’s nadir, where it would remain for the duration of their occupation. In the final hours of March 19, the Expedition-12 crew configured ISS for un-crewed flight and sealed themselves in Soyuz TMA-7. At 02: 49, March 20, Tokarev undocked the Soyuz from Zarya’s nadir and manoeuvred it to dock with Zvezda’s wake, at 03: 11. Korolev congratu­lated them for being the first crew to dock at all three Soyuz docking ports on ISS. The transfer was followed by a day of light duties, before the crew began reconfiguring the station for full occupation.

In March, a problem arose when blisters were found on EVA handrails during production on the ground. The blisters led to a questioning of the strength of the handrails on ISS and an instruction to only attach EVA tethers to the base of the station’s handrails, rather than the rail itself. Meanwhile, the crew spent time locating lithium hydroxide canisters to fit the Orlan EVA suits on ISS. New canisters would be launched on Progress M-56. They spent the remainder of their time on ISS preparing for the end of the Expedition-12 occupation, and their return to Earth. They also performed their last experiments. On March 29, they observed and photographed the total solar eclipse.

The Expedition-13 crew was launched in Soyuz TMA-8, at 21: 30, March 29, 2006. Korolev lost all telemetry links with the spacecraft for 10-15 minutes, shortly after it achieved orbit. The problem was caused by a communication outage with a Russian Molniya satellite. Onboard Soyuz TMA-8 all systems were performing as planned. The spacecraft docked to Zarya’s nadir at 23: 19, April 1. Following systems checks the hatches between the two vehicles were opened at 00: 59 the following day. Following the usual safety briefings Pontes transferred his couch liner from Soyuz TMA-8 to Soyuz TMA-7. He had trained for his flight as a temporary NASA astronaut, in return for an experiment rack to be mounted on the exterior of ISS. Budgetary difficulties prevented the Brazilians from producing the rack, but the flight of the Brazilian astronaut went ahead. In the next few days the two Expedition crews worked together to complete their hand-over while Pontes performed his own “Centenario” experiment programme. In all, Pontes completed 31 sessions with the 8 experiments, all in the Russian sector of the station.

Vinogradov was typically sincere in describing his duties as Commander of Expedition-13:

“[A]s the crew Commander, first and foremost I’m responsible for the safety of the crew, and my main task, the most important task is that we… return safe and sound back to Earth and have completed the flight program… The second thing is the state of the station. We understand that two or three of us are entrusted with the vehicle that’s valued at maybe hundreds of millions in dollars. It’s not even the question of its specific monetary value but tens of thousands of people worked on it and provided their labour and knowledge for its creation and we’re entrusted to control this complex setup. So that’s a responsibility that is quite significant for us, that we would not break anything or make it perform worse. So, that is quite a significant responsibility and that’s the second function of the crew Commander. The third important issue is our relationship as a crew, as a team. A small crew of two people creates a situation where even the smallest detail gains significant importance. Of course, spaceflight is different depending on its duration—during a short flight you can sort of do it as one feat, but a long spaceflight, you have to make sure that you pace yourself, that you distribute your strength evenly throughout the flight, and build the proper relationship with your crewmates. Even the smallest thing becomes quite important.”

He added:

“We will certainly be expecting the Shuttle and I’m hoping that it’s not going to be the only Shuttle that will visit us. Our task is to prepare the station to the maximum for the arrival of the Shuttle, and to be as effective as possible in terms of using the Shuttle flight… Those are our main tasks.’’

On April 3, McAthur and Williams “camped out’’ in the Quest airlock during their sleep period. Quest was isolated from ISS at 19: 45, and the pressure was lowered as planned. The two men began their sleep period, but 4 hours later they were woken by an error tone issued by software monitoring the atmospheric composition on ISS. Controllers in Houston decided to end the experiment at 01: 43, at which time the pressure was raised and the internal hatches opened.

The following day McArthur spoke to journalists during his preparations for return to Earth. He told them:

“By golly, it’s time to go home and spend some time with the family … It’s an absolute thrill and joy to live and work in space. But we miss the richness, the texture, the three-dimensional nature of living on our home planet. The coffee [on

ISS] tastes good, but it’s all in bags, and I’m really looking forward to smelling my cup of coffee. The next thing is food that crunches, like a good chef salad, and the sensation you get when you bite down of crunching into nice fresh lettuce or a raw carrot.’’

Earlier in the week Tokarev had commented, “We are ready to go home… We accomplished all of our tasks. We are happy, and we feel good.’’

Williams completed a training session with the SSRMS on April 5. He also received a briefing from McAthur on payload operations in Destiny. Meanwhile, Tokarev stowed equipment in Soyuz TMA-7 and reviewed undocking and re-entry procedures.

After a week of joint operations, Tokarev, McArthur, and Pontes sealed them­selves in Soyuz TMA-7 for their return to Earth. Undocking occurred at 17: 28, April 8. TMA-7 landed in Kazakhstan at 20:48, after 189 days 18 hours 51 minutes in space. Pontes had been in flight for 9 days 21 hours 17 minutes. Following their recovery McArthur described re-entry for reporters, saying:

“It was wild ride, we loved it.’’

Talking about the end of his flight he added:

“I feel an overwhelming sense of satisfaction and maybe even closure… I have a little muscle and joint soreness, but I feel strong.’’

On his return to Houston, he told the crowd:

“There are a lot of people here I’ve known for a very, very long time. That is the thing I missed, family and close friends, and I look forward to spending time with all of them.’’

Yurchikhin described the activities following the undocking of a visiting Shuttle in the following terms:

“What happens after the Shuttle goes back? First of all, we are always sorry to see them go because we are used to working together by that time. But after the Shuttle goes back to Earth… we’re going to have a lot of cargo items left [on ISS]

… First of all, when they’re unloaded into the station, we place them in temporary stowage locations. After that we’re going to open all the containers, pull out all the equipment, and then place the equipment in the allocated stowage areas… Then the next stage will be to activate this equipment…’’

With Atlantis gone, Yurchikhin, Kotov, and Anderson turned their attention back to the computers in the Russian sector of ISS. Two computers in each set of three were working through a jumper cable, but one computer in each set was working in a back-up capacity. On June 21, Yurchikhin powered up the two back-up computers which were also using a jumper cable to bypass a secondary power switch. As the station passed over a Russian ground station, he turned off the computers, removed the jumper cable, and attempted to re-boot the computers.

They failed to re-boot and were left powered off, with the jumper cable removed while troubleshooting continued at Korolev. During the day the Elektron oxygen generator began to produce oxygen for the first time since the computer crash.

Meanwhile, Anderson began his experiment programme, and completed his first Saturday Morning Science presentation for younger television viewers. He explained how Newton’s laws of motion applied to sports activities. As the new week began he collected blood and urine samples for a nutrition experiment that also required him to record all of the food and drink that he consumed. Anderson and Kotov also participated in a medical emergency exercise while Yurchikhin replaced an antenna in the Russian Regul communication system.

During the week they all performed regular housekeeping, including an inspec­tion of the windows in the Russian modules. They also worked on a number of Russian experiments. Kotov spent further time working with Korolev in an attempt to finally overcome the problem with the Russian computers in Zvezda. Anderson wore an “acoustic dosimeter’’ to record noise levels as he moved around the station, and his attempts to locate a leak in the MSG were unsuccessful. On June 28, Yurchikhin and Kotov worked with the Russian Profilaktika experiment, studying the long-term effects of microgravity, and Yurchikhin also worked with the Matryoshka radiation detection experiment, while Kotov inventoried medical supplies on the station. Propellant and oxygen was transferred to the station from Progress M-59 on July 11. Two days later Elektron was deliberately shut down. Meanwhile, the American Oxygen Generation System in Destiny was tested over the period July 11-14. The installation of new software in the Russian computers led to a successful re-boot of all Zvezda’s major computers on July 16. The computers were used to command the firing of Progress M-60’s thrusters, to raise the station’s orbit on July 21.

As July had begun, Yurchikhin and Anderson prepared the EMUs and Quest for their first Stage EVA together, scheduled for July 23. Yurchikhin and Kotov also continued to work with Korolev in an attempt to finally overcome Zvezda’s computer problems. Their painstaking inspections of the electrical system supplying the computers showed that one relay on the secondary power system was showing a lower voltage than expected. Inspection of the power-monitoring box that had been bypassed revealed moisture, in the form of condensation, inside. One connector was also found to have some corrosion on it and a second was discoloured.

When the reports on the Zvezda computer failure were finally released they pinpointed this corrosion as the cause of the entire problem. In the event of a major electrical power spike the system had been designed to shut down to prevent that spike crippling the system. Water vapour from the dehumidifier above the power­monitoring box had led to a build-up of condensation in the box. The moisture in the power-monitoring box and the corrosion in the connector pins had caused a power line to fail and short-circuit. That short-circuit had tripped the safety system and shut down the entire computer control system in the Russian sector. When the box was replaced by a new unit, delivered from ESA, condensation and microbial growth was discovered on the module’s wall behind the original box. When the new unit was installed, an old book was placed between the box and the spacecraft wall, to act as an insulation layer. With the new hardware in place the jumper cables were removed and the Russian C&C computer system was back in place.

Software upgrades were also completed on the computers in the American sector of the station, thus allowing them to support the addition of Node-2, Harmony, Columbus, and Kibo, as the station was expanded in the coming year.

Prior to the Stage EVA, the station was yawed through 180° so that PMA-2, on what had been Destiny’s ram now became the station’s wake. This was to provide a wider space for the two large items that would be jettisoned towards the station’s wake during the EVA. The EVA itself began at 07: 25, July 23, when Yurchikhin and Anderson left Quest and prepared their tools. Removing the stanchion for a television camera from the storage pallet on the station’s exterior, they moved to the P-1 ITS and installed the stanchion on the nadir face. They then split up for their next tasks. Anderson reconfigured the power supply for an S-band antenna assembly before placing the foot restraint in the open end of the SSRMS and climbing on to it. Meanwhile, Yurchikhin replaced a Remote Power Controller Module (RPCM) to ensure a redundant supply of electrical power to the Mobile Transporter on the wake face of the ITS.

Working together once more, they removed a Flight Releasable Attachment Module and other equipment, which Anderson jettisoned from the end of the extended SSRMS, which was controlled by Kotov from within Destiny. Kotov was the first Russian cosmonaut to be qualified to operate the SSRMS. Yurchikhin then made his way to the Z-1 Truss, where he disconnected and stowed cabling connected to the EAS, mounted on the P-6 ITS. The EAS had been installed by the STS-105 crew in 2001 and had contained an emergency supply of ammonia for use in case of a leak in the station’s cooling system. With the station’s permanent cooling system now active, the EAS was no longer required and had to be removed before the P-6 ITS was relocated. No leak had ever developed and the emergency ammonia supply had not been used. With Anderson working from the end of the SSRMS and Yurchikhin now on the P-6 ITS, they worked together to sever the final connections and remove the EAS from the P-6 structure. Anderson then held the EAS while Kotov manoeuvred him until he was below the ITS, where he pushed the EAS away from his body towards the station’s wake. NASA expected the tank to orbit Earth for up to 11 months before burning up in Earth’s atmosphere. Their final scheduled task was to clean Unity’s nadir CBM in preparation for the temporary relocation of PMA-3 during the flight of STS-120, then scheduled for October 2007. Finding themselves ahead of their scheduled timeline the two men were also able to complete three “get-ahead” tasks. They relocated an auxiliary equipment bag from the P-6 ITS to the Z-1 Truss, removed a malfunctioning GPS antenna from the S-0 ITS, and released bolts on two fluid trays, also mounted on the S-0 ITS. In the future, the trays would be re-located to the exterior of Harmony, following its delivery on STS-120. Yurchikhin and Anderson returned to the airlock, ending the EVA at 15: 06, after 7 hours 41 minutes. Following the EVA, ISS was rotated through 180°, to return PMA-2 to the station’s ram. The thrusters on Progress M-60 were used to boost the station’s orbit and prepare for the arrival of Progress M-61 and STS-118 later that evening.

Following pressure checks, Progress M-59 undocked from Pirs at 11:07, August 1. The spacecraft did not perform a separation burn, and Yurchikhin had to use the TORU manual control system to fire the de-orbit burn at 14:42. The Progress was destroyed as it re-entered the atmosphere.

With the departure of Soyuz TMA-7, the Expedition-13 crew began their 6-month occupation of ISS. If all went well the third member of this crew would be launched on STS-121, on April 1, 2006. German astronaut Thomas Reiter would become the first Expedition crew member that was neither American nor Russian. His arrival on ISS would raise the Expedition crew to three for the first time since May 2003, when the crew was reduced to conserve supplies in the wake of the loss of STS-107, Columbia. Reiter, an ESA astronaut who had spent a tour on Mir, was a commercial passenger flying under contract to the Russians.

Vinogradov and Williams had a light workload during their first weekend alone on the station before picking up the pace on the following Monday. On April 11, they had spent 3.5 hours performing maintenance on the station’s toilet. The following day, April 12, Russian President Vladimir Putin spoke to the crew from the Kremlin in Moscow, to mark the 45th anniversary of the first human spaceflight, made by Yuri Gagarin, in 1961. Vinogradov jokingly invited his President to visit the station. The same date was the 25th anniversary of the first Shuttle flight in 1981. The crew continued the task of loading rubbish in to Progress M-55, and completed the routine emergency evacuation drill early in their occupation.

Their third week on the station was filled with Williams performing American experiments and both men performing the first of three sessions on the Renal Stone Experiment. They also spent time preparing for the arrival of Progress M-56, includ­ing Vinogradov practising with the TORU system. On July 18, Korolev transferred propellant from Progress M-55 to Zvezda’s tanks. The following day a planned re­boost of the station’s orbit was cancelled when telemetry showed that one of the sunshades on Zvezda’s thrusters had not opened to its full extent. The malfunction was detected by the station’s software which then inhibited the ignition of the thrusters. The firing had been designed to test-fire two thrusters that had not been used since Zvezda docked to ISS, in July 2000. Engineers at Korolev began reviewing the problem and discovered that the opening of the sunshade had been impeded by an ATV antenna installed in September 2004.

Progress M-61 was launched from Baikonur at 13:33, August 2, 2007. After a standard rendezvous it docked automatically to Pirs’ nadir at 14: 40, August 5. The new Progress delivered a 2,569 kg cargo of propellants, water, oxygen, dry cargo, and personal items for the crew.

STS-118 was Endeavour’s first flight in 4.5 years, during which the orbiter had undergone extensive modifications. With Endeavour on the launchpad in mid-July, NASA engineers displayed the usual “Go Endeavour’’ banner on the gate across the bottom of the crawlerway ramp, only the banner in question read “Go Endeavor,’’ the American spelling, while the Shuttle’s name is spelt the British way, having been named after the Royal Navy ship sailed by the British 18th-century explorer Captain James Cook. When the mistake was pointed out the banner was quickly removed and replaced by one with the correct spelling. It was a small thing with no effect on the launch preparations.

In the run-up to launch, much of the media coverage centred on Barbara Morgan, who had first been selected to fly the Shuttle into space in the early 1980s, when she was one of two high school teachers selected for President Ronald Reagan’s “Teacher in Space’’ programme. Ultimately, Morgan was selected as the back-up and she watched the launch of STS-51L from the roof of the VAB, at KSC, on January 28, 1986. From there she saw the Shuttle explode, just 75 seconds into its flight, killing Commander Richard Scobee, Pilot Mike Smith, Mission Specialists Judy Resnik, Ellison Onizuka, Ronald McNair, Payload Specialist Gregory Jarvis, and high school teacher Christa McAuliffe. Morgan had returned to teaching before applying to become a full-time professional astronaut. She was subsequently selected as part of the 1998 astronaut group. When President George W. Bush announced his Educator Astronaut Project, a plan to select one professional educator in each subsequent annual astronaut group, Morgan was named as the first Educator Astro­naut in 2002 and began training as a Mission Specialist on STS-118. The original Teacher in Space and the Educator Astronaut Project had the same objective, to encourage America’s schoolchildren and college population to study mathematics, science, and engineering and to be generally inspired by the act of spaceflight itself. In her pre-launch interview Morgan remarked:

“I’m really excited about going up and doing our jobs and doing them well. I’m excited about experiencing the whole spaceflight, seeing Earth from space for the very first time and experiencing weightlessness and what that’s all about. I’m excited about seeing what it’s like living and working onboard the International Space Station.’’

To some journalists it seemed appropriate that Christa McAuliffe’s back-up should make the first Educator Astronaut flight on Endeavour, the orbiter that had been constructed to replace Challenger. On the subject of STS-51L, Morgan said, “The legacy of Christa and the Challenger crew is open-ended. I see this as a continuation. The great thing about it is that people will be thinking about Challenger and thinking about all the hard work lots of folks over many years have done to continue their mission.’’

NASA Administrator Michael Griffin was more succinct, stating, “Every time we fly I know that we can lose a crew. That occupies a large portion of my thoughts. Unless we’re going to get out of the manned spaceflight business, that thought is going to be with me every time we fly.’’

Morgan’s Educator Astronaut tasks were secondary to her other mission tasks; she would operate Endeavour’s RMS to provide images of the installation of the S-5 ITS, which would be manoeuvred into place by the SSRMS, mounted on the MT. The S-5 was a spacer, used to provide sufficient room to allow the S-6 SAWs to function correctly when they were installed. A similar unit, the P-5 ITS, was already in place. The S-5 and P-5 spacers, which were each the size of a compact car, also included all of the plumbing and electronics needed to ensure that the S-6 and P-6 ITS elements could function as part of the overall ISS power and cooling system. It would require three EVAs to complete all of the necessary connections to make the S-5 ITS an integral part of the ITS. Anderson explained:

“We add this little spacer, S-5, which we call ‘Stubby’—P-5 was ‘Puny,’ so you had ‘Puny’ on the left and ‘Stubby’ on the right—and you add that piece so that when STS-120 comes to bring me home… we’re going to take the P-6 module that’s been sitting up on top of the station since its arrival, they’re going to take that off, move it outboard on the P[ort] side and stick it on. So now we’ll have three sets of solar arrays…’’

Lead Shuttle Flight Director Matt Abbott described the flight in the following terms, ‘‘This mission has lots of angles. There’s a little bit of assembly, there’s some

re-supply, there’s some repairs, and there’s some high-visibility education and public affairs events. It’s a little bit of everything.”

As well as the S-5 ITS, STS-118 would also carry the last SpaceHab logistics module to ISS. SpaceHab was carried rather than an MPLM because the S-5 ITS left insufficient room in the orbiter’s payload bay for the latter. The crew would also replace the CMG, in the Z-1 Truss, that had failed in October 2006, using procedures similar to those employed by the STS-114 crew when they replaced a malfunctioning CMG in 2005. In its basic form, STS-118 was a standard 11-day flight to ISS. However, Endeavour would be the first orbiter to carry the Station-Shuttle Power Transfer System (SSPTS). As the name suggested, the SSPTS allowed electrical power generated by the station’s ITS SAWs to be transferred to a docked Shuttle orbiter, powering its systems. If the SSPTS worked correctly, flight managers would have the potential to extend the stay on ISS by up to 3 days, and even to add a fourth EVA to the flight. Future Shuttle flights might be extended by up to 6 days by using the SSPTS.

During the countdown, a faulty valve caused a pressure leak in Endeavour’s crew compartment. It was replaced by a similar valve, removed from Atlantis. The leaking valve, together with thunder storms that caused delays in the pre-launch work on the launchpad, led to the August 7, 2007 launch being delayed by 24 hours on August 3. The delay gave NASA the opportunity to launch the Phoenix probe, which only had a 3-week launch window if it was going to reach its proposed landing site on Mars.

STS-118 finally lifted off at 18: 36, August 8,2007. Representatives of some of the STS-51L crew members’ families were at KSC to see the launch. Ironically, given the media’s concentration on Morgan, members of the McAuliffe family were not among them. As Endeavour left the launchpad, ISS was over the Atlantic Ocean, southeast of Nova Scotia. Onboard cameras showed that nine pieces of foam separated from the ET and at least three appeared to strike Endeavour. The first was seen at T + 24 seconds, and looked as though it struck the body flap at the orbiter’s rear. The second piece was seen at T + 58 seconds, and resulted in a spray and decolourisation on the right wing. The third and subsequent pieces departed from the ET after STS-118 was above the sensible atmosphere and were therefore not thought to have had sufficient energy to damage the orbiter. A few minutes later, Endeavour was in orbit. In Houston, astronaut Rob Narvis announced, “… Class is in session.’’ Approximately 90 minutes after launch, a fragment of a Delta launch vehicle launched in 1975 passed within 2.4 km of Endeavour. Flight Day 1 ended at 00: 36, as the crew began their first sleep period in orbit.

Day 2 began at 08 : 37. During the first full day in space, Hobaugh, Caldwell, Mastracchio, and Morgan used the RMS to lift the OBSS from the opposite side of the payload bay at 11: 20, and spent the next 6 hours using its cameras and laser sensors to view the orbiter’s TPS. Elsewhere, the crew checked their rendezvous equipment, installed the docking system centreline camera, and extended Endeavour’s docking ring. During a television broadcast, Morgan told the audience, “Hey, its great being up here. We’ve been working really hard, but it’s a really good fun kind of work.’’ The day ended at 23: 36.

August 10 began at 07: 36. After eating their breakfast the crew commenced preparations for rendezvous and docking with ISS. Final rendezvous manoeuvres began at 11: 14, when Kelly performed the Terminal Initiation burn. He told the Expedition-15 crew, “We’re about 30,000 feet away. You’re looking very good.” Anderson replied, “All right, man, keep up the good work. We’re waiting for you.’’

Closing to within 200 m of the station, Kelly manoeuvred Endeavour through its r-bar pitch manoeuvre, allowing Yurchikhin and Kotov to expose a series of high – definition digital images of the orbiter’s underside, which were down-linked to Houston. When experts on the ground examined the photographs they identified a 7.5 cm x 7.5 cm gouge in the underside of Endeavour’s starboard wing, close to the main landing gear door. When he was told of the damage, Kelly replied, “Thanks for the update.’’ It was decided to carry out an OBSS inspection of the area with the orbiter docked to ISS.

Docking to PMA-2 on Destiny’s ram occurred at 14: 02. The hatches between the two spacecraft were opened at 16: 04, and Endeavour’s crew entered Destiny, where they were greeted by Yurchikhin, Kotov, and Anderson. After a short ceremony, the new visitors received the usual safety brief from their hosts. At 16: 17 the crew activated the SSPTS and electrical power produced by the ISS’ SAWs flowed into a docked Shuttle for the first time. One of the first activities following docking was Mastracchio using the RMS to lift the S-5 ITS out of the payload bay and hand it over to the SSRMS, operated by Hobaugh and Anderson. The S-5 ITS was then left on the end of the SSRMS overnight to acclimatise to the space environment. Work began at 18: 00 to unload the first of the supplies from Endeavour’s SpaceHab module. Meanwhile, Mastracchio and Williams spent the night camped out in Quest with the air pressure reduced, in preparation for their first EVA the following day.

In Houston, engineers had inspected the video from the various cameras mounted on the Shuttle during lift-off. They showed that the gouge on the underside of the right wing had been caused by a grapefruit-sized piece of foam that had shed from the ET and struck a bracket on the fuel line at the rear of the tank as it fell away. The impact had changed its course, leading to the impact with the underside of the right wing. Although the planned OBSS inspection would go ahead, NASA now felt sure that Endeavour could re-enter Earth’s atmosphere without the need for an EVA to repair the TPS. Mission Manager John Shannon stated, “It’s a little bit of a concern to us because this seems to be something that has happened frequently.’’

During the night, Endeavour’s crew was woken up by an audible alarm, which had activated because the use of the SSPTS had allowed one of the Shuttle’s fuel cells to cool down more than on previous flights. The alarm’s tolerance level was adjusted to take the lower temperature into account.

Endeavour’s crew was officially woken up at 07: 38; they then ate their breakfast. After supplying electrical power to Endeavour throughout the night, the SSPTS was powered off prior to the EVA, which began at 12: 28, August 11, after Hobaugh had used the SSRMS to position the S-5 ITS at the exposed end of the S-4 ITS. Mastracchio and Williams left Quest and made their way to the area, where they gave verbal instructions to assist in the final positioning of the new ITS element. The tolerances between the S-5 ITS and other parts of the station were at times only a few centimetres, and with no cameras in the area, verbal instructions were vital. They then set about bolting the new ITS in place and completing the electrical and plumbing connections between the S4 and S-5 ITS. The S-5 ITS was considered to be officially “in place” at 14:26.

At 15: 52, while the EVA was underway, the primary American Command & Control computer, in Destiny, shut down without warning. The back-up computer immediately assumed the primary role and the third, stand-by computer assumed the back-up role, exactly as they had been programmed to do. The EVA was not affected and ISS was never in danger. Controllers in Houston began troubleshooting the problem.

After installing the S-5 ITS, Mastracchio and Williams made their way to the P-6 ITS, where they retracted the forward radiator. This was the final task to prepare the P-6 ITS for its removal from the Z-1 Truss and relocation to the exposed end of the P-5 ITS. That task would be completed by the crew of STS-120, after they had temporarily installed Harmony on Unity. The STS-118 EVA ended at 18: 45, after 6 hours 17 minutes. The SSPTS was powered on after the EVA was complete and began supplying power to Endeavour once more.

August 12 began on Endeavour at 07 : 07 and was the day that the Shuttle crew inspected the damage caused to their vehicle by foam and ice shedding from the ET during lift-off. Hobaugh and Anderson used the SSRMS to lift the OBSS from its storage position, and handed it off to Endeavour’s own RMS at 09: 45. Kelly, Caldwell, and Morgan then spent 3 hours operating the RMS to view five damaged areas of TPS on the underside of Endeavour using the cameras and laser instruments on the OBSS to form a three-dimensional image of the damaged areas. Four of the five areas inspected offered no threat to re-entry. The fifth and by far the largest area was the 7.5 cm x 7.5 cm gouge seen earlier in the flight. Engineers in Houston would reconstruct the large gouge and test it under simulated re-entry heating temperatures. In the event that the gouge was found to threaten Endeavour during re-entry, the crew had three options for repair, all of which would involve an EVA:

• Apply a thermal paint to the exposed surface of the gouge.

• Install a cover plate of TPS material.

• Fill the gouge with a caulking material.

Throughout the day, Williams, Hobaugh, Mastricchio, and Drew spent their time transferring equipment and logistics from SpaceHab to ISS. In Houston, flight managers reviewed the operation of the SSPTS and extended the flight of STS-118, pushing Endeavour’s undocking from the station back to August 20, with landing 2 days later. The extra time would be used for a fourth EVA, by Williams and Anderson, to install a berth on the exterior of ISS to hold the OBSS. Just after 21: 00, Mastracchio and Williams began their second overnight camp-out in Quest, in preparation for their second EVA.

That EVA began at 11 : 32, August 13, when the two astronauts left Quest and made their way to the Z-1 Truss, using the SSRMS operated by Hobaugh and Anderson. Once in location they removed the CMG that had failed in October 2006. The failed CMG was carried to a temporary stowage location, while they installed a new CMG, which had been carried into orbit in Endeavour’s payload bay, mounted on External Stowage Platform 3. With the EVA progressing well, Caldwell told Mastracchio and Williams, “You guys rock.’’ The final task was to move the failed CMG from its temporary location to External Stowage Platform 2 on the exterior of ISS, where they secured it to await recovery and return to Earth on a later Shuttle flight. The EVA ended at 18: 00, after 6 hours 28 minutes.

Throughout the EVA, Drew continued to transfer equipment from SpaceHab to ISS, a task that other crew members assisted with once the EVA was complete. In Zvezda, Yurchikhin and Kotov continued searching Zvezda for the cause of the computer failure that had occurred during the visit of STS-117. On removing some wall panels in the Russian module they discovered that condensation had collected behind them.

In Houston, mission managers announced that the OBSS survey had shown that the largest gouge on Endeavour’s underside passed right through the TPS tiles and had exposed the felt that was laid between the TPS tiles and the orbiter’s aluminium skin. Discussions were underway as to whether or not the crew should make a repair before leaving ISS, but Mission Manager John Shannon told a press conference, “This is not a catastrophic loss-of-orbiter case at all. This is a case where you want to do the prudent thing for the vehicle.’’ He added, “we have really prepared for exactly this case, since Columbia [STS-107]. We have spent a lot of money and a lot of people’s efforts to be ready to handle exactly this case.’’

Shannon explained that it might be better to add a complicated TPS repair EVA to the flight, rather than risk more serious damage being caused during re-entry that would require long repairs and throw the already tight launch schedule into further disarray. He also assured journalists that mission managers had ruled out the second repair option, screwing a pre-prepared plate of TPS material over the damage, as the damage did not warrant such drastic measures. The choice now was between the thermal protection paint and the caulking material. On the subject of what this foam – shedding event meant to the launch schedule, Shannon would not be drawn, saying only, “We have a lot of discussion to have before we fly the next [External] Tank.’’

Endeavour’s crew began their sleep period at 22: 06.

Two events were marked during the August 14 working day. Endeavour’s crew were woken up at 06: 07, by a recording of Caldwell’s nieces and nephews singing, “Happy Birthday, dear Tracy,’’ to mark the astronaut’s birthday. Also, at 11: 15, Zarya, the first American-financed ISS module to be launched, completed its 50,000th orbit.

Caldwell and Morgan used Endeavour’s RMS to lift External Stowage Platform 3 out of the Shuttle’s payload bay, and hand it over to the SSRMS. Hobaugh and Anderson then moved it into position. The 4 m x 2 m platform, which held a second, spare CMG, a nitrogen tank assembly, and a battery charger/discharger unit, was attached to the P-3 ITS at 12: 18. The previous two ESPs had been installed on Destiny and Quest by astronauts making EVAs.

During the day, Kelly, Caldwell, and Morgan were interviewed by news organisations, and Kelly answered a question on the damage sustained by Endeavour during launch, saying, “My understanding is that the tile damage is not an issue for the safety of the crew. We may still choose to repair, but I’m not concerned with our safety.”

Morgan then joined Anderson, Williams, and Drew in answering questions from children at the Discovery Centre in Boise, Idaho. One child asked Morgan how being an astronaut compared with being a teacher. She replied:

“Astronauts and teachers actually do the same thing, we explore, we discover and we share. And the great thing about being a teacher is you get to do it with students, and the great thing about being an astronaut is you get to do it in space and those are absolutely wonderful jobs.’’

The video conference continued with the students asking questions on a wide range of subjects and receiving answers from the astronauts on Endeavour. Asked about what it felt like to fly into space, Williams replied:

“As soon as the engines stop, you float forward in your seat, your arms rise up, and it’s an incredible sense of freedom. The first thing we like to do is go up to the window and look at the Earth. It’s an amazing sight.’’

On the ground, mission managers were still awaiting heating tests before deciding whether or not to repair the gouge in Endeavour’s underside. They continually made it clear during the day’s press conferences that any repairs undertaken would be to prevent prolonged repairs after flight and were not a matter of preventing the loss of Endeavour during re-entry. Mastracchio and Anderson spent the day preparing for their third EVA, the following day. They spent the night “camped out’’ in Quest. The crew’s day ended at 22: 06.

August 15’s work day began at 06: 07. Mastracchio and Anderson left Quest at 10: 38 to begin EVA-3. The two men worked together to relocate an S-band Antenna Sub-Assembly from the P-6 ITS to the P-1 ITS. They also installed a new transponder on the P-1 ITS, before removing the transponder on the P-1 ITS. Both men watched while Hobaugh and Kotov used the SSRMS to relocate the two CETA carts from the track on the port side of the MBS to its starboard side. In so doing, they cleared the track to the port side for the MBS to complete the transfer of the P-6 ITS, from the Z-1 Truss to the outer edge of the P-5 ITS, during the flight of STS-120. Throughout the movement of the CETA carts, Morgan used the cameras on Endeavour’s RMS to provide live images of what was happening.

At 14: 54, Mastracchio carried out one of the new periodic checks of his EMU gloves and discovered a cut in the thumb of his left glove that had passed through the outer two layers of the glove’s five layers of construction. The cut did not puncture the gas bladder, there was no leak, and Mastracchio was in no danger. Even so, he was instructed to return to Quest and return his Extravehicular Mobility Unit to the electrical power supply inside the airlock. In Houston, NASA spokesman Kyle Herring told a press conference, “The suit is perfectly fine. This is just a precaution.’’ Anderson completed the final task before returning to Quest at 16: 05, after 5 hours

28 minutes. Plans to recover the MISSE-3 and MISSE-4 experiments were delayed until a later EVA.

Inside ISS, the remainder of the two crews spent the rest of the day on the transfer of equipment from SpaceHab to the station, which was half-complete. In Houston, mission managers delayed the fourth EVA from August 17 to August 18, but had not yet decided if it would be devoted to repairing Endeavour’s underside or to “get-ahead” tasks. Either way, on August 17 the crew would perform preparations for a repair, until managers told them that it was not required. If the repair went ahead, Mastracchio and Williams would ride on the end of the OBSS, which would be held in the end-effector of Endeavour’s RMS. They would be moved to the underside of the orbiter, where they would apply heat-resistant black paint to the gouge in the tiles then they would apply the caulking material to the gouge.

At 08: 06, August 16, Morgan and Drew spent time talking to students at the Challenger Centre for Space Science Education, Alexandria, Virginia. The centre had been set up by the families of the STS-51L crew. June Scobee-Rogers, the wife of STS-51L Commander Richard Scobee at the time of the STS-51L flight, was there to oversee the session. She began the session by greeting Morgan, “Barbara, we have been standing by, waiting for your signals from space for twenty-one years…’’ The questions that followed were many and varied. One student asked Morgan if she had had any special teachers in her own life. She replied that the seven people on STS-51L were mentors, “… that have meant more than anything to me. They were my teachers and I believe they are teaching us today, still.’’ As the broadcast ended, Morgan held an STS-51L mission patch up to the camera. The question-and-answer session was followed by interviews with a number of television and radio stations. Later in the day, Morgan also answered questions from the education district where she had been a high school teacher, during an amateur radio session.

The two crews spent most of the day transferring equipment between the two spacecraft, while Mastracchio, Williams, and Drew spent their time preparing for the fourth EVA and the repairs that they might have to make to Endeavour’s TPS. Just before the crew signed off for the day, Houston told them that the Mission Management Team (MMT) had decided that they would not carry out a repair to Endeavour’s underside. On receiving the news, Kelly replied, “Pass along our thanks for all the hard work the MMT and everyone down there is doing to support our flight.’’

In Houston, John Shannon told a press conference that the decision, “… was not unanimous, but pretty overwhelming.’’

The fourth EVA would now be dedicated to installing two antennae and a berth to hold the OBSS on the exterior of ISS between Shuttle flights. They would also recover the two MISSE trays that they had not recovered during the previous EVA. The day ended with both crews being given some off-duty time.

August 17 was another quiet day, with Mastracchio, Williams, and Drew preparing for the EVA now planned for the following day. The majority of the day was spent transferring equipment between the two spacecraft and talking with reporters in Houston and the Canadian Space Agency Headquarters in Montreal. Mission managers also had a new problem to consider, Hurricane Dean was approaching Houston, where the Shuttle control room was located. Plans were made to shorten the fourth EVA and even to undock a day early if the hurricane threatened the control centre. Mastracchio and Williams spent the night “camped out” in Quest when the crew began their sleep period at 23: 06.

The new day, August 18, began with a wake-up call at 05: 03. The crew were informed that due to the threat offered to Houston by the approaching hurricane the planned 6.5-hour EVA had been shortened by 2 hours. The shorter EVA would allow for the hatches between Destiny and Endeavour to be closed at the end of the day, preserving the option to undock one day earlier than planned. If required, mission control would move to a back-up facility at KSC, in Florida.

The final EVA began at 09: 17. Williams and Anderson installed the External Wireless Instrumentation System antenna, part of a system to measure stresses in the ISS structure. Next, they installed a stand for the OBSS, before recovering the two MISSE packages deferred from their previous EVA. Plans to secure micro-meteoroid shielding on Zvezda and Zarya and moving an external toolbox had been removed from the plan to facilitate the shorter EVA. During the EVA, ISS passed directly over Hurricane Dean, as it travelled across the Caribbean. Williams remarked, “Wow! Man, can’t miss that.” Anderson added, “Holy smoke, that’s impressive!” Both men returned to Quest at 14: 19, after an EVA lasting 5 hours 2 minutes.

Questioned during the crew’s joint press conference with the Expedition-15 crew about NASA’s decision not to repair Endeavour’s TPS, Kelly told journalists:

“I think it was absolutely the right decision to forego the repair… I think they took the appropriate amount of time to come to that conclusion.’’

He added,

“We have had Shuttles land with worse damage than this. We gave this a very thorough look; there will be no extra concern in my mind due to this damage.’’

Talking about the proposed repair, Mastracchio said:

“We were not looking forward to doing it, only because there was a lot of risk involved and a lot of long hard hours involved getting it all prepared… We felt comfortable we could go and accomplish it.’’

Williams had the final say:

“We [NASA] do not take chances; we manage risk. We are in the business of mitigating risk, and that is a data-driven process. To analyse all the appropriate data took time. They made the right decision. Going beneath the belly of the orbiter is something that has its own risk.’’

By 17: 10, the two crews had completed their goodbyes, during which Yurchikhin and Kelly embraced before the Russian told his American colleague, “Have a good

Figure 99. STS-118: the decision was made not to repair this tile damage on Endeavour’s underside. The damage to the orbiter’s heat protection system had no effect on re-entry, and Endeavour was recovered successfully.

trip back to Earth.” Kelly led his crew back to Endeavour. The hatches between the two spacecraft were sealed and both crews settled down to their respective sleep periods.

Endeavour’s wake-up call came at 04: 37, August 19. After final checks, Endeavour undocked at 07:56 and backed away from Destiny’s ram. As the two spacecraft separated, Yurchikhin rang the ship’s bell on the station and remarked, “Endeavour departed.’’ Anderson added, “Thanks for everything Scott, and Endeavour crew, Godspeed.’’ Kelly replied, “We couldn’t have gotten everything accomplished without you guys. We look forward to seeing you back on planet Earth.’’

After a partial fly-around of ISS, the Shuttle was manoeuvred clear at 08:23. Following a second burn, at 09: 30, the crew used the RMS to lift the OBSS and use it to inspect Endeavour’s nosecap and the leading edges of both wings. They berthed the OBS back along the payload bay door hingeline at 14: 37. At 16: 35 the crew began four hours of free time in advance of their sleep period, beginning at 20: 36.

The last full day in space began at 04: 37, and the crew spent the day stowing their equipment prior to re-entry. Kelly, Hobaugh, and Mastracchio tested Endeavour’s thrusters and aerodynamic surfaces. Kelly, Morgan, and Williams took time to talk to schoolchildren in Canada, before closing out the SpaceHab module. The day ended at 20: 36.

Overnight, Hurricane Dean had hit land in Jamaica, in the process losing most of its power. It was downgraded from a Category 5 hurricane to a Category 1 tropical storm. Endeavour’s crew were woken up at 04: 36, August 21, and at 07: 26 began their final preparations for re-entry. The payload bay doors were closed at 08 : 45 and retrofire occurred at 11 : 25, resulting in a landing at KSC on the first of two opportunities that day. Kelly landed his spacecraft in Florida at 12: 33, after a flight lasting 13 days 17 hours 56 minutes. As Endeavour rolled out to wheel-stop, Capcom in Houston told the crew, “Welcome home. You’ve given ‘Higher Education’ a new meaning.’’

After the toxic fuels had been pumped from the spacecraft the crew were allowed to leave. On reaching the ground Kelly walked underneath Endeavour to look at the gouge in the TPS. He later described it as, ‘‘Somewhat underwhelming… it looked rather small.’’ Small or not, that one gouge had been the subject of some 4,000 hours of computer time and NASA Administrator Michael Griffin praised the engineers who had carried out those studies. He later reminded journalists at a press con­ference, ‘‘This is very much an experimental vehicle. Anyone who doesn’t believe that just doesn’t get it.’’

As to the cause of the gouge, NASA engineers believed that ice had formed on the ET, causing the foam to break away from one of the brackets holding the fuel line. That foam had then struck a second bracket and changed direction, striking the TPS on the underside of the orbiter. The bracket had already been redesigned to minimise foam loss, but tanks with the new brackets were not scheduled to come on-line until spring 2008, with the flight of STS-124. In the meantime, engineers were considering removing some of the foam from the bracket on the ETs of the three Shuttle flights before STS-124.

Predictably, throughout the flight of STS-118 much of the media coverage had concentrated on Barbara Morgan. There had been endless words written and spoken about her role as the back-up Teacher in Space for STS-51L, and how “Challenger exploded in January 1986, killing high school teacher Christa McAuliffe and six other crew members.” Regretfully, 21 years after the event, most of the journalists had seemed unable to name the “six other crew members”, or thought it was unnecessary to do so in their reports.

Progress M-56 was launched from Baikonur at 12:03, April 24, 2006. The spacecraft docked automatically to Zvezda’s wake at 13: 41, April 26, bringing with it 2,597 kg of propellants, water, air, and dry cargo, including items from the crew’s families. The crew began unloading the new arrival the following day. During the week Vinogradov completed routine maintenance on the Elektron oxygen generator, which was deliberately powered off for the majority of the week. Williams dismantled his sleeping quarters in order to reach and replace a Remote Power Control Module in Destiny. The crew’s first month in orbit drew to a close with a series of routine tasks. Williams checked out the refrigerated centrifuge, sampled the potable water, and replaced the cooling water in the American EMUs. Vinogradov inspected the pressure hull in Zvezda and performed maintenance on the ventilation system. Both men installed new software in the station’s laptop computers and both also spent time packing unwanted items into Progress M-55. The week ended with a small reduction in nitrogen pressure in the Elektron unit. It was powered off and would remain off until after the Stage EVA planned for June 1. Additional oxygen from tanks in Progress M-55 was used to supplement the station’s atmosphere in the meantime. On May 4, Russian engineers fired Progress M-56’s thrusters to raise the station’s orbit. Four days later the crew had a day off, to celebrate Russia’s Victory Day. Williams trained with the SSRMS on May 11, using its cameras to return views of the station’s exterior. He left the SSRMS where its cameras could cover their EVA. Controllers in Korolev transferred propellant from Progress M-56 to Zarya on May 17.

The week had begun with a malfunction of the Vozdukh carbon dioxide removal system in the Russian sector. The carbon dioxide removal system in Destiny was activated while Russian engineers worked on the problem. Following its resolution, both systems were run in tandem until a new gas analyser was installed in the Vozdukh the following week. The remainder of the week saw Williams experimenting with a small satellite called Synchronised Position Hold, Engage, Reorient Experi­ment Satellite (SPHERES) inside Destiny. The satellite, the first of three, was programmed to perform a series of manoeuvres in anticipation of “constellation’’ flying at a later date, after two more satellites had been delivered on STS-121. The manoeuvres, using small carbon dioxide thrusters, consisted of 15 ten-minute trials during which the satellite went through a series of pre-programmed flight manoeuvres, including object avoidance and station keeping. The technology might be developed in future as automated assistants for space crews. NASA reported:

“Each satellite is about 8 inches in diameter, weighs about 7 pounds, and has its own internal avionics, software and communications systems. They are powered by 2 AA batteries and will use carbon dioxide gas thrusters to manoeuvre through the Destiny lab. As the satellites fly through the station they will communicate with each other and the ISS laptop through a wireless link.’’

Elsewhere, Vinogradov reconfigured ventilation lines associated with the Elektron oxygen generator. The maintenance had been planned before the unit was powered off due to the nitrogen pressure drop. The crew spent time packing items for return to Earth on STS-121 when Discovery visited the station.

The last full week in May was spent preparing for the EVA planned for July 1. The crew gathered together the equipment they would use, charged the batteries in their Orlan suits, and checked out Pirs. During the week Vinogradov replaced a gas analyser in the Vozdukh system, returning it to full working order. They were also the first people to spot a new eruption of a volcano on the Aleutian Islands in Alaska. Williams began using the InSPACE experiment, last used by the Expedition-7 crew, studying the behaviour of fluids that change their properties when subjected to a magnetic field.

At 18:48, June 1, Vinogradov and Williams opened the hatch on Pirs to begin their first EVA, the 65th devoted to the construction and maintenance of ISS, and the last planned to be completed by a two-person Expedition crew. After gathering their tools they used a Strela crane to place themselves at Zvezda’s ram, where Zvezda docked with Zarya’s wake. In that location, Vinogradov installed a new nozzle on a valve used to vent hydrogen overboard from the Elektron. The original valve had become clogged, causing Elektron to use the same vent line used by a contamination­monitoring device. Two weeks earlier Vinogradov had installed an internal line inside Zvezda as a precursor to fitting the new valve on the exterior. Elektron would be powered on, on July 7.

With that task complete, they moved to Zvezda’s wake, where they photo­graphed one of the antennae designed for use by the European ATV. The antenna’s cable was suspected of having been the cause of the thruster sunshade not fully opening during their third week of occupation, thus causing the aborting of a re­boost manoeuvre. Vinogradov then recovered the Kroma device, designed to collect thruster residue, from Zvezda’s exterior. Meanwhile, Williams collected the third Biorisk package from the exterior of Pirs, along with a contamination-monitoring unit, also from the exterior of Pirs. With those three units safely stored inside Pirs, the EVA was extended, before handing over control from Korolev to Houston. Using the Strela crane once more, they manoeuvred themselves to the area where the Russian and American sectors of the station met before moving past Quest and on to the ITS. Control of the EVA passed from Korolev to Houston. In that location, Williams installed a foot restraint and removed a video camera from the MBS replacing it with a new one. The original camera had failed in February 2005. Korolev resumed control of the EVA once more as the two men used the Strela to return to Pirs and re-enter the airlock. The hatch was closed at 01: 19, July 2, after an EVA lasting 6 hours 31 minutes.

On the same day Programme Manager Wayne Hale reviewed progress on the Shuttle’s foam-shedding problem for the media saying:

“We are on a road for continuous improvement… We are trying to eliminate the biggest hazards and work our way on down… We have found no showstoppers. We believe we have made significant improvements… There will continue to be foam coming off the external tank. What we have done in a very systematic manner is eliminate the largest hazards.’’

The following week was spent cleaning, servicing, and storing the suits they had worn during their EVA, before concentrating on preparations to jettison Progress M-55, receive Progress M-57, and STS-121, Discovery’s Return to Flight mission, which was due to deliver an MPLM full of logistics to ISS. They also had to work on the Elektron unit, which only restarted after several attempts and then failed 7 hours later. Russian engineers decided that the unit had a malfunctioning power unit, which would require replacement with a spare already held on the station. The malfunction had no immediate impact on operations. The crew also ran their regular experiment programme. On June 9, Progress M-56’s thrusters were fired in a re-boost man­oeuvre, placing the complex in the correct altitude to receive Progress M-57.

The crew spent much of the second week of June preparing for Discovery’s arrival, practising the photography session during which they would take images of Discovery as she performed the new r-bar pitch manoeuvre prior to docking with the station. June 12 was a day off, celebrating Russia’s Independence Day. Two days later the last of the propellant was transferred between Progress M-55 and Zarya. Both men also spent time packing rubbish into Progress M-55 and sealed its hatches on June 16. It was undocked at 10:06, and commanded into the atmosphere where it burned up on June 19. Vinogradov spent time practising with the TORU manual docking equipment in case he might have to assume control of Progress M-57 during its final approach. The end of the week involved performing experiments. Vinogradov also replaced internal panels and smoke detectors inside Zvezda, while Williams trained with the SSRMS, practising the manoeuvres he would use to remove the MPLM Leonardo from Discovery’s payload bay and dock it to Unity.

With the Shuttle gone, the Expedition-15 crew was alone on ISS once more. They quickly adjusted their sleep pattern and returned to their daily routine of exercise, maintenance, and experiments. Anderson has described some of the experiments in which he would take part:

“You know, some of them are quite simple. For example, scientists on the ground want to know what I eat, how much I eat and drink, and how often I eat and drink, and they want to know my vitamin-D content. Well, vitamin-D is some­thing we get from sunlight on Earth, primarily, but we need it for strong bones and muscles, and so folks, elderly folks that have trouble with bones and osteoporosis and those kind of problems can benefit by the scientists that are doing experiments and gathering data on how a crew member in space that doesn’t get sunlight anymore and has to supplement his vitamin-D with either drugs—or vitamin tablets—and what he eats and what he drinks, and that’s a key experiment that’s pretty simple. They just have to gather the data. Another experiment that’s quite interesting to me is I’m going to wear a special watch, for the entire increment, and it’s called an actiwatch, and it’s a sleep watch: it knows when you move, it knows when you go to sleep, it knows when the lights go on and when the lights go out, and scientists will gather that data that we’ll downlink periodically through the mission. What they’re trying to do is try to figure out ways to benefit people on Earth that do shift work or that have trouble sleeping or that sleep too much, and ways to work with your circadian rhythm and your body and try to help you not go through these periods when you can’t stay awake or when you can’t go to sleep. So that’s quite neat. And those are simple experiments. The more complex experiments include things, we’re going to look at combustion on the station through an experiment that has… several samples that just rotate through a chamber and they look at the flammability and take the data and then they’ll evaluate it on the ground. We’ll grow some plants, we’ll grow some worms, and the key there, of course, is when you go on long duration, can you grow plants, can you eat those plants, how do physical things like worms adapt to zero-g in a long-duration mission, such that we can apply that to humans.’’

As to his spare time, Anderson had plans of his own:

“From a personal standpoint, I like to write music and I’m going to try to write a song when I’m in space. Now I don’t know how much time I’ll have, I don’t know how successful I will be. The other thing I’d like to do is there’s a guitar on board and I’ve always wanted to learn to play guitar and hopefully I’ll have enough time and there’s some software on our computers that will try to guide me through the learning process to learn how to play the guitar. I think what I want to do the most, though, is I want to try to absorb as much as I can, all that I experience and see while I’m there, and try to take as much of that with me as a memory either through video media or computer e-mails or what have you, but I want to try to take as much of that away as possible so I can relate it to people back here on Earth.’’

PMA-3 had been delivered to ISS by STS-92 in October 2000 and installed on Unity’s nadir. In December of the same year, STS-97 had docked to it in that location in order to install the P-6 ITS on the Z-1 Truss. STS-98 had also docked to PMA-3, in order to install Destiny, in February 2001. During the visit of STS-102, in March 2001, PMA-3 was moved from Unity’s nadir to Unity’s port CBM, thus allowing Unity’s nadir CBM to be used for the berthing of MPLMs carried by Shuttles docked to PMA-2 on Destiny’s ram. On August 30, 2007, the Expedition-15 crew relocated PMA-3 in preparation for the arrival of STS-120. Anderson operated the SSRMS from inside Destiny, while Yurchikhin operated the relevant CBM docking mechanisms on Unity. Kotov backed up both of his colleagues. After latching the end-effector of the SSRMS onto PMA-3, Yurchikhin commanded the docking system on Unity’s port CBM to release and Anderson removed the PMA at 09: 18. During the undocking a fault alarm sounded when one of the latching bolts registered zero load. The work was stopped to study the situation before continuing. During the relocation fault, alarms sounded intermittently on three securing bolts and work was stopped a second time to further review the situation. Finally, Houston gave the command to continue. After Anderson had manoeuvred PMA-3 next to Unity’s nadir CBM, Yurchikhin commanded Unity’s docking mechanism to close, holding the PMA in place at its new location. The move was completed at 10: 07.

The relocation of PMA-3 was required so that Harmony could be temporarily docked to Unity’s port CBM. This temporary installation on Unity was necessary because the SSRMS could not reach to install a PMA on Harmony’s ram if the new module was docked directly to Destiny’s ram when it was delivered by STS-120. When STS-120 had departed, the SSRMS would be used to undock PMA-2 from Destiny’s ram and move it to Harmony’s port. Next, the SSRMS would be used to move Harmony, with PMA-2 on one end, and docking, via its exposed CBM on the other end, to Destiny’s ram, leaving PMA-2 exposed on Harmony’s ram to receive visiting Shuttles. Zvezda’s thrusters were fired on September 24, to adjust the station’s orbit in advance of the launches of Soyuz TMA-11 and STS-120, planned for October 10 and October 23, respectively.

Anderson updated the software in the American navigation systems and installed new American computer hardware, and Kotov tested and upgraded the Russian computers before the two computer systems were integrated as one system.

The station was re-oriented on September 11, to reduce drag as it passed through the upper atmosphere. It was estimated that the manoeuvre would save the equivalent of the total amount of manoeuvring propellant for Zvezda’s thrusters delivered on two Progress flights. Onboard, both loops of the Russian thermal control system suffered a single pump failure, leaving both loops operating on just one pump each. Repairs made by Kotov on October 3 returned one loop to full operation, the second loop would have to await the delivery of a new pump on Soyuz TMA-11. Both men worked to replace Russian EVA support equipment in Zvezda and Pirs on September 19-20. The original equipment had passed its use-by date.

Even as preparations for the arrival of STS-120 continued, Yurchikhin and Kotov were also preparing for the end of the stay on ISS. Progress M-60 was undocked at 19: 37, September 18, but was not commanded to re-enter immediately. Rather, it was commanded to perform six manoeuvres as part of the “Plasma – Progress” experiment. Progress M-60 finally re-entered on September 25.

As the Expedition-15 crew brought their experiment programmes to an end, they also began packing to go home. Before that could happen they had to relocate Soyuz TMA-10. On September 27, having prepared the station for unoccupied flight, all three men donned their Sokol pressure suits and sealed themselves in the Soyuz, which was docked to Zarya’s nadir. Yurchikhin undocked his spacecraft at 14: 20 and manoeuvred clear of the station before flying along its length and manoeuvring to dock at Zvezda’s wake. Docking occurred at 14: 47 and the crew returned to the station after leak checks. They then began the task of reconfiguring the station for occupation once more. The move cleared Zarya’s nadir for the docking of Soyuz TMA-11, flown by the Experdition-16 crew. That launch was planned for October 10.

The following day, September 28, Zarya’s starboard photovoltaic array was retracted. This was required to prevent impact with the starboard radiator, mounted on the ITS, that would be deployed during the visit of STS-120. Zarya’s port photovoltaic array was retracted on September 29, to prevent impact with the port radiator, which would be deployed after STS-120 had left the station. Meanwhile, on September 30, STS-120 was transferred from the VAB to LC-39A, in preparation for its launch on October 23.

In Destiny, Anderson activated the American Oxygen Generation System and measured the sound levels that the machinery produced on October 2. The new oxygen generator was set at 50% and left running, while Houston monitored its performance. When running at full power the American system would provide sufficient oxygen to fill the entire station at “Core Complete’’ plus the International Partners’ modules. It would be capable of supporting the entire station, even when operated by six Expedition crew members.

The MT/MBS combination was moved to the port side of ISS on October 3, in preparation for the arrival of STS-120 and the relocation of the P-6 ITS. Moving the P-6 ITS from the Z-1 Truss and relocating it to the far end of the port side of the ITS, and the installation of the S-6 ITS on STS-119, represented the ultimate tasks that the SSRMS would be called upon to perform during the construction of ISS. The SSRMS would be operating fully extended and at the extreme limit of its reach.

On the same day, the crew reopened the hatch to Progress M-61, which they had sealed prior to relocating Soyuz TMA-10.

October 4, 2007 was the 50th anniversary of the launch of Sputnik-1, the world’s first artificial satellite. Asked about the significance of the anniversary in a pre-launch interview, Expedition-16 crew member Yuri Malenchenko said:

“I believe we have achieved a considerable progress over such a short time period. We learned to live in space just a short 50 years ago, but didn’t live in space. We weren’t even thinking, or rather we were thinking, but weren’t sure if it is possible, to live in space constantly. Currently we have a continuous presence of humans in space, not only living in space but performing complicated activities and tasks, performing science experiments, and it has been going on for years. Of course, space exploration is unique. All steps, all achievements, regardless of where, which country and when, have been completed, are important, and each step is an important stage for subsequent steps.’’

The Expedition-15 crew marked the anniversary onboard ISS, but also had to continue with their own work as well as their preparations for the arrival of Soyuz TMA-11 and their own return to Earth. Meanwhile, Anderson worked with Kotov to use the Oxygen Uptake Measurement equipment to collect data as he exercised on the stationary bicycle. The Oxygen Generation System in Destiny continued to operate at 50%, waiting for the system’s water supply to be depleted. During the week before the launch of Soyuz TMA-11, the crew mounted the centreline camera in Unity’s port CBM, where it would be used in support of the initial docking of Harmony during the flight of STS-120. The three men also completed the medical experiments and extra exercise that all long-duration crews perform as their flight approaches its end. They also made room in Zvezda where the Soyuz TMA-11 spaceflight participant would perform his experiments during his short visit to the station.

On October 6 the TVIS treadmill in Zvezda failed during Kotov’s exercise period. The crew worked with engineers in Korolev to replace three roller bearings and return the vital unit to use. As they prepared for their return to Earth, Yurchikhin and Kotov continued to work with both Russian and American experiments.

When Soyuz TMA-11 launched towards ISS at 09:21, October 10, 2007, it contained an extremely experienced crew. Soyuz Commander Yuri Malenchenko served 126 days on Mir and had commanded the 185-day occupation of ISS as part of the Expedition-7 crew. He had also visited ISS during the 12-day flight of STS-106. Whitson had made two Shuttle flights, serving as Pilot. Whitson had also served on ISS for 185 days as part of the Expedition-5 crew. Following the Soyuz TMA-11 crew’s transfer from Soyuz to the station, she would become the first woman to command an ISS Expedition crew. Sheikh Muszapher Shukor was a commercial customer of the Russian Federal Space Agency on his first flight. On launch day, Russian engineers presented Whitson with a ceremonial Kazakh riding whip and suggested that she might use it to keep her male colleagues in line while on the station. Asked about how she viewed being the first female Commander of ISS, Whitson replied:

“I think being a woman doesn’t really play too much into that. I think it’s special that I get the opportunity to play that role, but I think it’s also special to have an opportunity to demonstrate how many other women also work at NASA. So I’d like to be able to do that as well.’’

In answer to a different question she explained:

“Actually it’s going to be kind of exciting. During STS-120 Pam Melroy will be commanding that Shuttle mission; my lead flight director is Holly Ridings. I also have Lead Flight Directors for two different Shuttle missions during those phases, Dana Weigel and Sally Davis. And so we have a big team, which is consistent with any mission, but it happens this time around we have a number of females in the leadership roles. So I think it’s exciting.’’

Soyuz TMA-11 lifted off from Baikonur at 09: 22, October 10, 2007. As was the standard procedure, during the launch and solo flight, Malenchenko served as Soyuz Commander. Following a standard 2-day rendezvous, Soyuz TMA-11 docked to Zarya’s nadir at 10: 50, October 12. After leak and pressure checks the hatches between the two spacecraft were opened at 12: 22 and Whitson led the Expedition – 16 crew on to ISS. After the standard safety brief, Shukor and Anderson moved their seat liners and Sokol pressure suits between the two Soyuz spacecraft, Anderson thus becoming a member of the Expedition-16 crew and Shukor preparing for his return to Earth in Soyuz TMA-10 with the Expedition-15 crew. The next 9 days were spent in joint experiment programmes while the new crew, who were both ISS veterans, also took time to re-associate themselves with the station. Shukor performed his experiment programme in Zvezda. That programme consisted of five Malaysian experiments and three ESA experiments. In a Malayan press release, he was identified as the country’s first angkasawan (astronaut). Meanwhile, Anderson replaced a failed audio terminal unit in Quest on October 11. The new unit would lock up during the Soyuz TMA-11 hand-over period. Houston began an investigation.

On October 16, China expressed an interest in getting involved with ISS. Li Xueyong, a Chinese minister of science and technology, stated:

“We hope to take part in activities related to the International Space Station. If I am not mistaken, this programme has 16 countries currently involved and we hope to be the 17th partner… The Chinese government has always pursued a foreign policy of peace and consistently worked for the peaceful use of outer space.”

In Whitson’s first in-flight press conference, the subject of Russian cosmonauts’ attitude towards their female colleagues was discussed. The new station commander remarked, “Russian cosmonauts are very professional. Having worked and trained with them for years before we got to this point makes it better.’’ Yurchikhin added, “It’s not a problem, women running operations. The problem is whether we are professional or not. We are professionals. She is our friend and colleague.’’ On the same subject, Anderson joked, “I’m a little concerned about this whip. I’m kind of waiting for her to take it out and put me in line sometimes.’’

After a week of shared maintenance, experiments, and daily exercise, the official hand-over of command took place on October 19, at which time Whitson told Yurchikhin and Kotov, “It’s been a very impressive mission, and you guys have performed exceptionally.’’ Yurchinkhin, Kotov, and Shukor said their farewells the following day and sealed themselves in Soyuz TMA-10. They undocked from the station around 03: 14, October 21. Following the standard retrofire manoeuvre, Soyuz separated into its three parts. The descent module re-entered the atmosphere but soon deviated from its planned trajectory and followed a much steeper, ballistic trajectory. The course change had been commanded by the onboard computer. After a re-entry in which the crew pulled higher ^-forces than planned, the spacecraft’s parachutes deployed and lowered Soyuz TMA-10 to a safe landing in Kazakhstan, at 06: 37. The Expedition-15 crew had been in flight for 196 days 17 hours 5 minutes. Shukor’s flight had lasted 10 days 21 hours 14 minutes. Although the landing was 338 km south of the target, the recovery forces had tracked its descent and recovery helicopter crews had the descent module in sight as it descended on its parachute. After removal from the module by the recovery forces, the cosmonauts used the satellite phone, added to the Soyuz spacecraft after a similar re-entry trajectory switch by Soyuz TMA-1, to speak to Korolev. Talking about the re-entry afterwards, Yurchikhin stated:

“The overload was really powerful, but nobody fainted… I remember the overload going to 8.5 or 8.6 g.’’

Shukor was more descriptive, stating:

“I was not really scared, it happened so fast… It felt like an elephant pressing on my chest, but the Russians trained us very well.’’

On the subject of his flight he remained optimistic, saying:

“I hope to go back and inspire a generation of Malaysian youth… I hope other Muslims would be united, stay away from war and be peaceful.’’

STS-120 DELIVERS HARMONY, “THE PIECE THAT MAKES THE REST POSSIBLE”

In the days leading up to the launch of STS-120, a degradation of the outer protective coating was observed on the leading edge of both of Discovery’s wings. One RCC panel on one wing and two on the other showed the degradation, which had been present for the past three of Discovery’s flights. Launch managers decided that the problem fell within the limits of acceptable risk and decided not to roll STS-120 back to the VAB and replace the panels in question. A roll-back would have caused the flight to be delayed by a minimum of two weeks.

Rain threatened on the morning of launch, but in the end the weather held back. One technical problem that had threatened to delay the launch was a build-up of ice on a propellant line under the left wing. By the time the countdown reached its final stages, the ice had melted sufficiently to offer little threat to the Shuttle.

Discovery lifted off on time at 11: 38, October 23, 2007, after what Launch Director Michael Leinbach described as, “One of the cleanest countdowns we’ve had since I’ve been a Launch Director.’’ Discovery passed through a succession of cloud layers as it sped towards orbit. Melroy reported that several pieces of ice struck the orbiter’s forward windows during launch, but did no damage. All observed ice shedding from the ET took place after the critical first 2.5 minutes of flight, by which time Discovery was beyond the thick lower atmosphere, where the supersonic slipstream might slam the ice into the orbiter, causing damage.

On NASA’s website, Commander Pam Melroy had shared her enthusiasm for the flight, saying:

“STS-120 is such a cool mission. Node-2 is the expansion of the Space Station’s capability to bring international laboratories up. It’s the expansion of our capability to carry additional people. It has additional life support equipment that will allow us to expand out beyond a three-person crew. It’s this big boost in capability which is really exciting.’’

With lift-off behind them, the crew opened the payload bay doors to deploy their vital radiators and deployed the Ku-band antenna before spending several hours configuring their spacecraft for orbital operations, before settling down to their first eat and sleep period at 17 : 30.

On ISS, Whitson and Anderson worked on the TVIS treadmill, while Malenchenko serviced the toilet in Zvezda. The following day, Malenchenko serviced the KOB-1 and KOB-2 Thermal Control Loops performing a major plumbing overhaul that returned both systems to partial operation.

Up again at 01: 30, October 24, the STS-120 crew’s first full day in space was occupied by using the OBSS on the end of the RMS to inspect Discovery’s Thermal Protection System, including the RCC panels on the leading edges of both wings. An initial review of the data showed no immediate problems for re-entry at the end of the flight. They also prepared the EMUs stored in Discovery’s airlock as well as the equipment they would use during the rendezvous and docking the following day, including installing the centreline camera and extending the docking ring. Inside the orbiter, a high-speed computer modem presented the one difficulty of the day. The modem was due to be used to download the crew’s digital photographs to MCC-

Houston. On ISS, Anderson was approaching the end of his 4.5-month occupation, and was undergoing an increased daily exercise regime, in preparation for his return to Earth. Anderson and Malenchenko also prepared the cameras they would use to photograph Discovery’s underside during the now standard r-bar pitch manoeuvre prior to docking. Whitson performed pressure leaks in PMA-2 in advance of Discovery’s docking. The Shuttle crew’s day ended at 17: 38.

Awake once more at 01: 39, October 25, Melroy’s crew ate breakfast together before making the final preparations for rendezvous with the station. Melroy began the rendezvous manoeuvres just before 03: 00. Two hours from docking Anderson told Discovery’s crew, “We can’t wait to see you. We welcome you with arms open. The towels are clean and laid out.’’ At 07: 32, at a range of 200 metres below the station, Melroy had Discovery perform a nose-over-tail pitch manoeuvre so that Anderson and Malenchenko could photograph the TPS on the Shuttle’s underside. Those digital images were sent to MCC-Houston, so that specialists could search them for evidence of any damage caused by the ice or foam shed from the ET during launch.

Docking, with Melroy at the controls, occurred at 08: 40, off the coast of North Carolina, and was greeted with cheers from both crews. On ISS, Whitson rang the ship’s bell and announced, “Discovery arriving.’’

Parazynski remarked, “Everyone here is ecstatic. We are so fired up to be here.’’ As usual, docking was followed by pressure and leak checks, before the hatches between the two spacecraft were opened 2 hours later. As the hatches opened, Whitson, the first female commander of ISS, greeted Melroy, only the second female commander of a Shuttle flight. Before launch Melroy had talked about this moment, saying, “The most important thing to me is the picture we take when our hands first meet across the hatches.’’ In Russia, before her own launch, Whitson had sounded less enthusiastic about the meaning of that handshake, saying, “I look forward to their arrival… She thinks it will be a special moment.’’

In reality, Whitson embraced Melroy as she entered Destiny. The media-hyped meeting, as the female commanders in charge of two separate spacecraft, was pure coincidence, caused by the delays in past Shuttle launches. Originally, STS-120 had been scheduled to launch before Whitson took command of Expedition-16.

The remainder of Melroy’s crew were greeted with handshakes and hugs. After the formal greeting onboard the station and the standard safety brief, Discovery’s crew began moving spacewalking equipment into the Quest airlock. At 12: 12, Tani installed his couch liner and Sokol launch and re-entry suit in Soyuz TMA-11, becoming part of the Experdition-16 crew, while Anderson moved his equipment into Discovery, transferring him to STS-120. As the day ended, Melroy’s crew were told that initial inspection showed no damage to Discovery’s Thermal Protection System. Melroy replied to the news, saying, “Oh, man. That is fantastic news. Obviously, that was a question that has been on our minds.’’ Parazynski and Wheelock spent the night “camped out’’ in Quest, in preparation for the first EVA the following day.

October 26 began at 01 : 39. After breakfast, Discovery’s crew commenced preparations for their EVA. Wheelock and Parazynski exited Quest at 06 : 02, half an hour earlier than planned, at the beginning of a planned 6.5-hour excursion. Italian astronaut Nespoli choreographed the EVA from inside Discovery. As the preparations came to an end and Quest was depressurised, Whitson joked, “We’ll open the hatch so you guys can go out and play.’’

Parazynski replied, “They call it work, but there is no better job, is there?’’ As the outer hatch swung open, Parazynski was awed by the view of Earth and remarked to Wheelock, “You’re not going to believe this.’’ Their first task was to remove a malfunctioning S-band antenna from its position on the Z-1 Truss and store it in Discovery’s payload bay for return to Earth. They also disconnected the final umbilicals running between the Z-1 Truss and the P-6 ITS, in preparation of the latter’s relocation later in the flight. Parazynski was subjected to a small ammonia leak while disconnecting the umbilicals and had to undergo cleaning procedures after returning to Quest at the end of the EVA. As they passed over the Gulf Coast, Wheelock remarked enthusiastically, “Oh, boy, look at that; Hello, Houston.’’ Returning to the payload bay, they put in place a payload and data grapple fixture that could not be mounted on Harmony during launch, due to lack of room within the closed payload bay doors. Their next task was to disconnect the umbilicals supplying electrical power and cooling fluids to Harmony. Tani, Anderson, and Wilson then grappled the new module with the SSRMS, lifted it out of the payload bay, and manoeuvred it to its temporary location on Unity’s port CBM. It was the first new pressurised module to be added to ISS in six years.

As the EVA drew to a close, Parazynski remarked, “Great day in outer space.’’ The ammonia decontamination procedures were first used on STS-98 and consisted of partially pressurising Quest, venting the airlock to vacuum once more, in an attempt to remove any residue ammonia crystals, before pressurising Quest to allow the other astronauts to briefly open the internal hatch, pass in wet towels, and close the hatch once more. The two EVA astronauts then wiped down the exterior of each other’s EMUs, before bagging the towels and finally leaving the airlock to return to the station. The EVA ended at 12: 16, after 6 hours 14 minutes.

Flight Director Dereck Hassaman described Harmony in the following terms:

“It’s the gateway to the International Partners. As the station is configured today, there’s nowhere to put the International Partner modules until we deliver and activate Node-2. That’s the piece that makes the rest possible.’’

Flight Director Rick LaBode added:

“We’re going to put it on the left side of Node-1 [Unity], and then, after the mission undocks, we’ll robotically remove the port the Shuttle docks to [PMA-2] from the end of the lab [Destiny] and put it on Node-2 [Harmony]. And then we’re going to take the Node-2 [with PMA-2] and put it on the end of the lab.’’

In orbit, with the job of delivering Harmony already completed, Parazynski stated, “Now the crews that are hot on our heels have a place to come.’’

As the day continued the Mission Management team in Houston decided to add an unplanned task to the second EVA, planned for October 28. The starboard SARJ had been experiencing increased friction over the previous 6 weeks. Parazynski and Wheelock would remove the thermal covers and make a 360° inspection of the joint.

Meanwhile, October 27 began at 01: 39. After breakfast, Whitson and Nespoli worked together to prepare Unity’s port CBM, before the crew opened the hatch giving access to the interior Harmony. That happened at 08: 24, when the hatch was swung back allowing Whitson and Nespoli to become the first people to enter the new module. All crew members wore surgical masks during their first visit to the new module in case there was any loose debris floating around that might be inhaled. With Harmony only in a temporary location, their task was not to power up the module before preparing it for the arrival of Columbus and Kibo. Rather, they applied minimal electrical power and installed a temporary ventilation line to circulate air into Harmony’s interior. Later in the day the two crews used the new Node to host a press conference, during which Whitson remarked, “We think Harmony is a very good name for this module because it represents the culmination of a lot of International Partner work and will allow International Partner modules to be added on.’’ Melroy added, “This is a really special moment for the station. This kicks off the international science portion of the Space Station’s life cycle.’’ Flight Director Rick LaBrode told the media, “It’s beautiful; bright shiny. The report from the crew is that it’s as clean as can be. Perfect shape!’’ Melroy also praised the work of the other members of both crews during the previous day, saying, “I just sat around and made lunch for everyone, and watched them do a totally fantastic job.’’

During the morning Discovery’s OBSS was returned to its storage position along the orbiter’s payload bay hingeline. The second inspection of Discovery’s Thermal Protection System, planned for that morning, had been cancelled the previous day. During the remainder of the day, Tani reviewed the plan for him to inspect the SARJ during the second EVA, and he also spent time with Anderson, working on hand­over procedures. At 15: 23, as the crew’s day ended, Parazynski and Tani were locked inside Quest and the pressure was dropped, to allow them to “camp out’’ overnight, in preparation for their EVA the following day.

The crew’s wake-up call on October 28 came at 01 : 09. After breakfast, Parazynski and Tani donned their EMUs inside Quest, while Wilson and Wheelock manoeuvred the SSRMS to grasp the P-6 ITS, mounted on the Z-1 Truss. Exiting the airlock at 05: 32, Parazynski remarked, “It’s a beautiful day,’’ and Tani replied, “Awesome.’’ After collecting their tools they made their way to the base of the P – 6 ITS, where they disconnected the final electric cables and the bolts that held the structure in place. Wilson and Wheelock then lifted the P-6 ITS away from the Z – 1 Truss. The 15 m long P-6 was left hanging overnight on the end of the SSRMS. Meanwhile, the two EVA astronauts set about performing separate tasks. Parazynski moved to the exterior of Harmony, where he installed EVA handrails. Tani made his way to the starboard ITS, where he checked the CETA cart for sharp edges on its handrails and then moved on to the SARJ, where he removed the thermal covers and inspected the joint for friction points. He discovered the joint was covered in a black dust, which included metal shavings, and there was friction wear on the race ring, then he replaced the covers. Station managers decided to limit the amount of rotation that the joint was subjected to while the investigation into problem continued. Tani also reconfigured connections on the S-l ITS that would allow Houston to deploy the S-l cooling radiator at a later date. For their final task they worked together to install a second PDGF on the exterior of Harmony, by which it would be held during its transfer from Unity’s port side to Destiny’s ram. They also removed launch covers from the exterior of Harmony. The EVA ended at 12:05, after 6 hours 33 minutes. After the EVA, NASA’s Mike Suffredini commented to a press con­ference regarding the port SARJ, “I really don’t think we are in any situation we can’t recover from. It’s just a matter of time. We have an obligation to try and get our partners to orbit as quickly as we can.’’

October 29 was a day of robotic work, with astronauts inside ISS and Discovery moving the P-6 ITS around outside the station. The day began at 01: 39 and after breakfast the two crews set about their individual tasks. Parazynski and Wheelock had a relatively quiet day preparing Quest and the station’s EMUs for the third EVA, with Nespoli’s assistance. Meanwhile, the remainder of the two crews separated into their own work teams. Wilson and Zamka operated Discovery’s RMS while Anderson and Tani operated the SSRMS. At 04: 08 the RMS was manoeuvred to grapple the P-6 ITS, after which SSRMS was commanded to release it. Discovery’s RMS held on to the P-6 ITS while the MBS holding the SSRMS was commanded to travel to the far end of the port ITS, from where it would still be stretched to its limits to install the P-6 ITS in its final location. The MBS translation along the port ITS took 90 minutes.

Tani has described his activities during the 3 days of work required to relocate the P-6 ITS:

“Conceptually it’s not that difficult: It’s four bolts—very big bolts but four bolts—it’s about a dozen electrical connectors and, and some fluid connectors. During the first couple of EVAs we will disconnect the electrical connectors; on the second EVA I will help unbolt the actual element. We’ll have Doug Wheelock inside running the arm. He will initially move the P-6 out and away from the station. Now the difficulty here is that the arm is not long enough to take it from its initial position and move it out to its final position. So we have to do a juggling act. We move it out to the side of the Space Shuttle and I believe Stephanie [Wilson] or George [Zamka] will then grab the P-6 Truss so that the Space Station arm can let it go, and then we utilize the Mobile Transporter, which is this little rail car that’s on the truss, and they’ll drive this little rail car, with the Space Station arm on it, all the way out to the end of the truss as far as they can go. Then the next day, I’ll run that Space Station arm to go pick up the P-6 Truss again and hand it off from the Shuttle. On the next EVA, I’ll run the arm and we’ll do a final install during the EVA with Doug and Scott outside, to do its final install and bolt it to the end of the truss and then redo those electrical and fluid connectors… right now the P-6 solar arrays have been fully retracted. It’s a big element but at least it doesn’t have these huge wings hanging off them. It’s hard to think of an analogy, but we are adding a huge source of power to the Space Station, or we’re moving it, and the power reconfiguration to protect all the circuitry, once you hook that up, is very extreme. In fact, we’ll have to power down half the Space Station while we do this because you don’t want to do what we call a ‘hot mate’. You don’t want power in one connector and have arcing across these connectors. So we will be powering down half the Space Station while we do this. We mate the P-6 to the P-5 and then, as soon as we can, once the electrical connectors are made, the folks on the ground will start powering those channels back up and we will start attempting to deploy these solar arrays.’’

During the MBS translation, Whitson and Tani worked inside Harmony, installing avionics racks. The remaining crew members spent most of the day trans­ferring items from Discovery to the station. During the day, Houston informed them that an additional day had been added to the flight plan, giving them a day of additional light workload between EVA-4 and EVA-5. Also plans were added to try and clean the starboard SARJ during EVA-4. As a result of the last point an inspection of the port SARJ was added to EVA-3 in order to provide data with which to compare the descriptions of the starboard SARJ obtained during EVA-2. No attempt would be made to repair the port SARJ on this flight. The changes meant that plans to test a space age caulking gun, designed to be used to repair gouges in the Shuttle’s Thermal Protection System caused by foam or ice impacts during launch would be abandoned and moved to a later Shuttle flight. As the day ended, Parazynski and Wheelock were shut inside Quest and the pressure reduced, in preparation for EVA-3 the following day. Meanwhile the Mission Management Team had studied the effect of stopping the continuous rotation of the starboard SARJ, which was a reduction in electrical power production. The reduced electricity supply would be sufficient to support the launch of Columbus, then scheduled for December 2007, but might not support the addition of Kibo, due to be launched in early 2008. Work would continue to resolve the problem.

October 30 began at 00:38. After breakfast, Parazynski and Wheelock began dressing for their EVA while the RMS and SSRMS teams began their own prepara­tions for the hand-off of the P-6 ITS and its re-installation on the far end of the P-5 ITS. The two astronauts left Quest at 05 : 45. The P-6 ITS was offered up on the end of Discovery’s RMS towards the SSRMS, now positioned on the end of the port ITS. After the hand-off to the SSRMS, the P-6 ITS was manoeuvred and then offered up to the exposed end of the S-5 ITS. With few cameras in the area, Parazynski and Wheelock were there to give verbal instructions. Following a successful re-mounting, the two astronauts drove home the four bolts and completed the connections with the P-5 ITS and the station’s power system. This move and the similar installation of the S-6 ITS represented the design limits of the SSRMS, even so the two teams on ISS made the task look simple. As all astronauts are pleased to acknowledge, this was all down to the highly professional nature of their training and the dedication of their training teams.

Parazynski then moved to the port SARJ and removed the thermal covers. He described the joint as ‘‘pristine’’. The EVA ended at 12: 53, after 7 hours 8 minutes, but on getting out of his EMU, Parazynski discovered a small hole in the outer layer of the thumb on his right-hand glove.

As the EVA reached its final moments, controllers in Houston commanded the first SAW to deploy on the P-6 ITS. When it was fully extended, Discovery’s crew commanded the second SAW to deploy. When it had deployed to approximately 30 m, 80% of its full length, Melroy called a stop, “We’ve detected something that appears to be a wrap-around or some damage.’’ Houston replied, “We see it.’’

The live television pictures in the control room showed a tear in the SAW. Programme Manager Mike Suffredini later told a press conference, “This will take time and needs to be worked, but my personal opinion is we’ve got the time to work this issue, so we can be methodical about it, and we will.’’ The remainder of the day was spent discussing the new problem, transferring items from Discovery and talking to the press.

October 31 began at 00: 38. As breakfast ended, Parazynski and Wheelock began configuring a spare EMU to replace Parazynski’s original suit, which had suffered from cooling problems during the third EVA. Together with Nespoli, they would spend the day preparing for the fourth EVA, which was now planned for November 1, and would be dedicated to a thorough inspection of the starboard SARJ and sampling of the debris seen in the joint during the second EVA, as well as trying to identify the root cause of the friction. Meanwhile, Whitson and Tani worked inside Harmony, removing launch restraints and deploying the Zero Gravity Stowage Rack. On the subject of Harmony, Whitson explained:

“Node-2, Harmony, like Node-1 [Unity], has six different ports that we can add modules on to, to build the station. So it’s, it’s our next big connecting piece in our puzzle of putting this huge station together on orbit. Node-2 is required to power and provide the thermal heat rejection for the science laboratory modules that’ll be coming up, the one built by the European Space Agency and the one built by the Japanese Space Agency. So it’s a pretty key module for us, for the continued development of the station.’’

As the day proceeded, the priorities for STS-120 changed. Although the ripped SAW on the P-6 ITS was producing 98% of the electricity that it would if fully deployed, Houston decided to make it the priority for the remainder of Discovery’s flight. The fourth EVA would be slipped back 24 hours, to November 2, or even November 3, if more time was required for preparation, and would now concentrate on repairing the ripped P-6 ITS SAW before the damage got any worse. The Mission Management Team decided that the priority was to fully deploy the SAW and thus hopefully prevent further damage. Initial plans called for Parazynski to carry out the repair while riding the end of the OBSS mounted on the SSRMS, while Wheelock provided verbal instructions for Wilson and Tani operating the SSRMS. The repair itself would consist of threading wire through holes in the SAW blanket on either side of the tear and using an aluminium strip to support it from beneath, thus closing and supporting the tear in much the same way as a cuff-link works on a man’s shirt sleeve. Meanwhile, in Houston, Suffredini was blunt:

“I need this array. We believe over time we could tear the blanket further. If we do enough damage, we could potentially get into a configuration where we could not stabilise the array. If we can’t, we have to figure out what to do. We don’t have a lot of options, and the most likely option is that we would have to jettison it.’’

He continued:

“The station is a robust vehicle. We have many options with how to deal with the problems. It’s not a situation where anyone is particularly panicked. But on the other hand, we want to get this fixed to a point where we can continue with the assembly the way we planned… This is not about style points. It doesn’t have to look good. It just has to produce power.’’

Suffredini also paid a compliment to the team of engineers who had been working on the problem since the torn SAW was first identified:

“We give this team a little time to start thinking about creative solutions, and it doesn’t take them long to blow you away with what they come up with.’’

During the afternoon press conference with the crew, the President of Italy congratulated Nespoli on his flight, but predictably the conversation returned to the damaged SAW. Melroy described what she had seen as the second SAW deployed:

“It was a tough situation. The Sun was shining directly into our camera views. At one point, we did stop because we were concerned we had lost our big picture. We can second guess ourselves, and there may have been something we could have done, but I think we certainly aborted as soon as we saw something that was not right.’’

Parazynski added:

“My initial take was the guide-wires that became frayed earlier may have been the culprit. However, it looks to our eyes, via the binoculars and photos, like the guide-wires may be intact.’’

During the day the fourth EVA was pushed back to November 3, to give ground teams more time to come up with a work schedule and to give the astronauts additional time to prepare. Even so, Whitson, Commander of ISS, remained con­fident stating, “If there is a way to do this, we will figure out a smart way to come up with whatever workaround we need to make it happen.’’

The crew spent the remainder of the day making the hinge stabilisers that they would install when they repaired the SAW and preparing their EMUs. At one point Ex-President George Bush Senior and his wife Barbara visited the control room in

Houston and were able to talk to the crew. Talking to Melroy, he told her, “Good luck to you. Pam, we want to wish you well and all of your team. We’re so proud of your team… Barbara and I.’’

November 2 began at 01: 38 and was another day of preparation. During the morning, controllers moved the MBS back from the far end of the P-5 ITS to the centre of the ITS. There it was used to take hold of the OBSS and remove it from Discovery’s payload bay hingeline. The OBSS was then handed to Discovery’s own RMS, where it would stay overnight, while the MBS moved back to the far end of the port ITS.

In Houston, NASA made the media aware of some of the risks involved in making repairs to a SAW that was still actively producing electricity. Astronaut David Wolf, head of the EVA branch of the Astronaut Office, said, “We are faced with a difficult situation. At some point, we have to execute the plan we’ve got, as long as it’s very safe, instead of having a perfect plan and having it be too late to execute.’’ He added, “It’s a real test of the adaptability of this team, of our baseline knowledge of how to work in space … We have some risks here.’’

The two rips, one just under 1 m long and one 0.3 m long, would be repaired using five bracing straps made from 12-gauge wire with a 10 cm long aluminium strip at each end. The aluminium strips would be fed through existing holes in the SAW to hold the damaged areas together along a 5 m length. The straps, which the team that developed them had begun calling “cuff-links’’, varied in length from 1 m to 2m. To prevent an electrical discharge and possible injury to Parazynski, Kapton tape, an insulating material, had been wrapped around each of the straps, as well as the tools that would be used and the exposed metal parts on the outside of Parazynski’s EMU. The panel was “live’’, with up to 100 volts of electricity passing through it, and could not be turned off. As a result, the two EVA astronauts had been instructed in which parts of the P-6 ITS represented shock hazards. At the end of the day, Parazynski and Wheelock “camped out’’ in Quest under reduced pressure.

November 3 began at 01 : 38 and breakfast was followed by the hand-off of the OBSS from Discovery’s RMS to the SSRMS. The EVA started at 06:03. Melroy encouraged her two crew members as they left the airlock with the call, “Go out there and fix that thing.’’ Parazynski replied, “We will.’’ Even so, Houston warned, “Time is of the essence.’’

Having mounted the OBSS, Parazynski spent 90 minutes being swept through 180° of open space, taking him from the centre of the ITS to the worksite 30 m above Quest and 50 m out to the port side of the station. As he watched Earth sweep by below him, he told Houston, “This is just indescribable. Words just can’t do it justice. At least, not mine.’’

On arrival at the damaged area, he found that the guide wires used during the SAW’s deployment were damaged, but the wires carrying electrical current were not damaged. His helmet camera showed a view of the deployment guide wires that he described, “It appears severely frayed.’’

Melroy viewed the area with binoculars from Discovery and described it as a “furball’’. She added, “I’m sure that is causing shudders on the ground somewhere.’’ Tani told Parazynski, “You are a dot to us.’’

Parazynski cut one of the guide wires with an insulated tool, and Wheelock, working at the base of the SAW, used a pair of pliers to feed it into the relevant take – up reel. Parazynski then installed the five cuff-links, poking the aluminium straps through existing holes in the SAW. As the EVA ended, Parazynski sighed, “What an accomplishment?” Whitson complimented them, “Excellent work guys. Excellent.” With the repair complete, just past 11:00 controllers in Houston began com­manding the SAW to complete its deployment. Fifteen minutes and 13 computer commands later the SAW was deployed to its full extent. Meanwhile, it took an hour to sweep Parazynski back through open space to the centre of the ITS, from where the two men made their way back to Quest, closing the hatch at 13: 22, after an EVA lasting 7 hours 19 minutes.

Lead Station Flight Director Derek Hassman called it, “One of the most satisfy­ing days that I’ve ever had in Mission Control.” Suffredini was equally enthusiastic, “We are in great shape, fixing the array lets us get on with the assembly… This was just a fabulous effort. Our baby is still beautiful to us.’’

The remainder of the day was spent clearing up after the EVA and transferring equipment. While electricity from the P-6 ITS 2B SAW was integrated into the station’s main power supply, that from the repaired 4B SAW remained isolated while testing of the repaired SAW continued.

November 4 began at 02: 08, before the clocks were put back an hour for the change from edt to est. During the morning briefing, Houston told the two astro­nauts, “This will go down as one of the biggest successes in EVA history. Words cannot express how proud you made everyone with the execution by the entire team.’’ After breakfast the two crews completed the final transfer of items between the two spacecraft before beginning to get ready for Discovery’s undocking. 992 kg of new supplies were now on ISS, in addition to Harmony, while 916 kg of scientific samples and other items would be returned to Earth in Discovery. Anderson’s occupation of ISS was at an end, but like everyone else before him he was in two minds about how he viewed the prospect of leaving the station:

“I have a lot of blood, sweat and tears left aboard the International Space Station. What we are doing here is very important for all of human kind. It’s worth the risk. It’s worth the cost… Five months ago I was on my back preparing to launch and wondering what the heck I had gotten myself in to. Now, I’m poised to return to Earth after having served very proudly… Part of me is ready to go and part of me wants to stay.’’

After saying their formal farewells, the two crews locked arms and swayed back and forth to music, laughing together and some of them even shed a few tears. At 12: 28 Melroy led her crew, including Anderson, back to the Shuttle, closing the hatch between the two spacecraft at 12: 03. Whitson, Malenchenko, and Tani remained on the station to continue the Expedition-16 occupation.

A 02: 38 wake-up call on Discovery on November 5 was followed by a quick breakfast and final preparations for undocking. Zamka backed Discovery away from PMA-2 at 05: 32. In Destiny, Whitson rang the station’s bell to mark their departure.

She told them simply, “Thanks, guys.” Zamka performed a full 360° fly-around of the station while the crew photographed and videoed its new configuration from all angles. Back opposite PMA-2, Zamka performed the separation burn at 07: 15. Discovery’s crew spent the day using the OBSS mounted on the end of the RMS to inspect the orbiter’s wing leading edges and nosecap for damage sustained while in flight. They found none, and Discovery’s TPS was cleared for re-entry. Anderson spent the day exercising in the mid-deck, in advance of his return to Earth.

Discovery’s last full day in space, November 6, began at the 02: 38. Melroy and Zamka undertook the standard test of the orbiter’s flight surfaces and thrusters. The remainder of the crew spent the day packing for re-entry. During the afternoon Anderson’s recumbent chair was set up on the mid-deck and the Ku-band antenna was stowed. As Discovery passed over KSC, Melroy noted, “We can see the runway from orbit. So, the weather is looking pretty good.’’ Discovery had been planned for a night landing, but Melroy had asked for the flight plan to be changed in favour of a daylight landing, due to the unintended length and complexity of the flight.

During the day, Melroy talked to the media about how she felt “extremely concerned’’ for Parazynski’s wellbeing during the EVA to repair the 4B SAW.

Parzynski recalled, “It was a phenomenal personal experience to be out on the end of the boom.’’

Anderson discussed his mental preparations for his return to Earth, “I’ve enjoyed my time up there immensely, and it’s kind of a bittersweet time for me to come home, but I’m ready.’’

The final day of STS-120 began at 02: 38 November 7. Following breakfast, preparations for re-entry began at 08 : 03. Discovery’s payload bay doors were closed at 09: 20. Melroy and Zamka began preparing for the de-orbit burn, turning Discovery to a tail-first attitude before igniting the rocket motors at 11: 59. When the burn was complete, Melroy turned the orbiter so that its flat underside faced the on-coming atmosphere. Following the standard radio blackout caused by the sheath of ionised air surrounding the vehicle, Melroy flew a series of large, sweeping S-turns in the sky to bleed off energy. Finally, approaching Florida she flew the spacecraft across the state and headed out over the ocean as Discovery turned around the heading alignment circle to line it up with the end of the Shuttle Landing Facility at KSC. Melroy put the rear undercarriage on the runway at 13 : 01, after a flight lasting 15 days 2 hours 23 minutes. Anderson had been in space for 152 days.

After the flight, Melroy described the mission emotionally, saying, “What you saw is who we are at NASA.’’ NASA’s Administrator Michael Griffin watched the landing from alongside Runway 33, KSC. He took a similar tone when he described the flight to reporters as, “NASA at its best.’’