MORE COMPUTER TESTS

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.