Category The Story of Manned Space Stations

In March 1970, the Skylab project received official approval by President Nixon when he referred to it during a speech about America’s goals in space for the coming decade and beyond. However, this was a difficult time for NASA, they had achieved President Kennedy’s challenge of landing a man on the moon before 1970, indeed they had done it twice with Apollo 11 and 12, and now they faced the inevitable post­success anticlimax, and the people of the United States lost interest. The Soviet threat to the moon landings had failed to materialize, and the risks of further moon landings were all too clearly demonstrated during the flight of Apollo 13 in April 1970. NASA’s budget had been slowly reducing for years now, and finally they had to cut flights: two Apollo missions were deleted from the program that would now end with Apollo 17 in 1972. It was at this time that the first hint of co-operation with the Soviets became apparent, with a suggested docking of a Soyuz with the Skylab workshop. This was at a time, of course, when the Soviet’s plans for their Salyut stations was completely unknown to the Americans until Salyut 1’s launch in 1971. NASA then suggested that perhaps an Apollo CSM could dock with a Salyut station, but the Soviets were not keen on this idea, and NASA had already decided that a Soyuz docking with Skylab was also not an option any longer. These discussions continued, and eventually an Apollo-Soyuz docking was suggested, and this would lead to the Apollo-Soyuz Test Project (ASTP) of 1975.

In 1971 Chief of Flight Crew Operations, Deke Slayton, began the process of selecting crews for the upcoming Skylab missions. At that time, three missions were definitely scheduled with the possibility of two more. It had also been suggested that the crews should consist of one pilot/commander, preferably a flight experienced astronaut joined by two scientist-astronauts in order to maximize the scientific output from these flights. Slayton quickly put a stop to that idea; his feeling was that Skylab was a totally new kind of mission, and he wanted two pilot astronauts on each crew in case something went wrong. He came up with the following crew assignments based on those criteria.

Even these initial assignments had undergone some change. Walt Cunningham had originally been assigned as back-up commander for the first flight, but he choose to leave NASA rather than stick around for another two years as only a back-up. He was replaced by Rusty Schweickart, who in turn was replaced on the Skylab 2 and 3 back-up crews by Vance Brand. Also added at a later date was the possibility of a Skylab Rescue mission. This was the first time that planning a rescue mission had even been possible in NASA’s space program. It involved flying a special Apollo Command and Service module fitted with two extra couches underneath the outer­most couches already installed; this was a small area that had been used as a sleeping space during Apollo moon missions. This modified CSM would be flown by a crew of two, and come back with five crewmembers after docking with the second port on Skylab.

It was at this point that some confusion entered the Astronaut Office concerning the design of the mission patches for Skylab. The official designation for the three manned flights was SL-2, SL-3, and SL-4, with the first unmanned launch of the lab itself designated SL-1. The crews had designed their patches according to this numbering, but were later informed by the Skylab Program Director that in fact their flights were being referred to as Skylab 1, 2, and 3, so the patches were changed. When the patches were submitted for official approval, they were rejected by NASA’s Associate Administrator for Manned Spaceflight, Dale Myers, because of their numbering, and he ordered them to revert to the original designations. However, it was too late for the crews to do this, as their clothing for their upcoming missions had already been stored on board Skylab ready for its launch. It was deemed far too expensive, and unnecessary to change the clothing and labels at this late stage, so although the office designations for the missions remained, the patches are labeled, 1, 2, and 3. Such are the difficulties of managing a space program!

With the flight crews and launch dates now defined, some modifications were required to the launch pads to support the launch of the Saturn IB rocket. This had been used only once previously for a manned launch, when Pad 34 had been used for the Apollo 7 mission. As that pad was no longer available, it was decided to modify Pad 39B to accept the Saturn IB, and leave 39A largely as it was to launch the last ever Saturn V booster with the Skylab workshop on board. Given that most of the upper connections on the much shorter Saturn IB were the same as for the Saturn V that Pad 39B had been designed for, it was decided that the easiest modification to the pad would be to build a 127 foot high pedestal for the Saturn IB to sit on. This pedestal became known as the milkstool.

The Skylab workshop itself had undertaken quite a journey. Built originally as the second stage of the Saturn IB launch vehicle, it now had to be converted into a useable orbital workshop. S-IVB second stage number 212 had been built in 1966 by McDonnell Douglas, and its accompanying J-2 rocket engine built and tested during 1967 and then installed into stage 212 later that same year. At that point in time this stage was not assigned to a specific mission, so it was put into storage at McDonnell’s Huntingdon Beach assembly plant until March 1969. At the end of this period it was identified as being ideal for refurbishment as the Skylab orbital workshop. As 1969 progressed, the J-2 engine, thrust structures, and various other parts were removed to

leave the stage consisted only of its two fuel tanks. It took a further two years of work to prepare the interior of the hydrogen tank for human habitation in space. The second smaller tank, originally intended for liquid oxygen, would be used by the crew for storing all of their trash. By the end of 1972 the Saturn S-IVB stage 212 was ready to be launched as the primary Skylab workshop. At the same time, another S-IVB stage, number 515, this time from a Saturn V, had been identified as the back-up Orbital Workshop and had gone through the same conversion process as stage 212. It never flew, of course, and it was delivered to the Smithsonian Institution for display at the Air & Space Museum in Washington D. C., where it has been since July 1976.

Before any of the announced crews could visit the station, it was decided to run a full mission length simulation on the ground. This simulation would allow all the experiments and equipment aboard the station to be tested before launch. It would also help to alleviate any medical fears regarding the crew’s long-term exposure to a artificial closed ecological system. If there were any problems, it would be better that they happened first on the ground. In order to run the simulation as accurately as possible, a complete mock-up of the Skylab interior had to be built in an altitude chamber in order that the correct pressure and mixture of gases could be used. It was

decided to use the 20 foot diameter chamber at the Manned Spacecraft Center in Houston. The program was known as SMEAT, which stood for Skylab Medical Experiments Altitude Test. Originally planned to consist of two simulations, one lasting for 28 days and a second lasting for 56 days, it was decided to limit the program to just one 56-day test. The crew for the SMEAT test was to be selected from the pool of existing astronauts, but not to include any of the selected Skylab crews, their back-ups or support crew. Bob Crippen was selected as commander, with Karol Bobko as pilot and Bill Thornton as science-pilot. They designed their own mission patch, which featured the cartoon character Snoopy with a tightrope around his neck; this was said to reflect how they felt about some the medical experiments that were to be performed on them.

On the 26th July 1972 the three men prepared to start their marathon simulation with a medical check before beginning a long pre-breathing period to purge nitrogen from their blood. During the “mission” the crew participated in all the experiments that the actual crews would perform in flight. This allowed them to discover any problems with procedures, and to set a baseline for the experiments that were to be performed in orbit. The test ended on 20 September 1972, and undoubtedly made a massive contribution to the success of the Skylab missions.

By the end of 1972 the Skylab program was ready for its first launch. The thirteenth and final Saturn V booster to be launched would be used to haul the Orbital Workshop into space, where it would be visited and lived in by three separate crews launched by Saturn IB boosters from an adjacent pad. With the crew of the first mission watching, the Saturn V lifted itself from Pad 39A, and at first, everything appeared to be quite normal.

Unfortunately just as the vehicle was passing through Max Q (a term for maximum aerodynamic pressure) about 70 seconds after launch, the first signs from telemetry showed that the booster was in trouble. The telemetry showed that the micrometeoroid shield and the number two solar array had already been deployed. This, of course, should have been impossible, for the Skylab workshop was still surrounded by the aerodynamic launch shroud. In fact, the shroud enclosed only the structures atop the OWS. The skin of the OWS was the S-IVB, which was exposed to the airflow. However, the Saturn V continued its pre-programmed path and delivered Skylab to orbit. It now remained to be seen what condition the lab was in. Initial telemetry suggested that there had been a major problem with the solar arrays, as the amount of power being generated by them was a small percentage of what it should have been. Clearly if the station could not generate enough power, it could not be occupied for any length of time. After more detailed investigation by NASA officials, it was determined that a design imperfection had caused the micro­meteoroid shield to move away from its flush location against the workshop, and aerodynamic forces had then ripped the entire shield away, taking the left-hand solar array with it. It was uncertain whether the right-hand array had been similarly lost, or was trapped against the lab by debris from the departing shield. It was hoped that the

latter was the case. Pete Conrad’s crew were stood down until they could be trained to free the trapped array. Unfortunately, the micrometeoroid shield was to have served as the thermal shield to keep the interior of the workshop cool. With its demise, the internal temperature was climbing steadily to the point where it would exceed the limits designated safe for human habitability. The obvious thing for ground con­trollers to do was to maneuver Skylab such that the area of bare skin was pointed away from the Sun in order to keep the internal temperatures under control. How­ever, this also meant facing the remaining solar arrays, which were located on the Apollo Telescope Mount, away from the Sun, thus depriving the fledgling station of power. Eventually the Skylab controllers alternated the station between different attitudes in an effort to find the best compromise. A further complication caused by the increasing internal temperatures was the condition of the food supplies aboard the station for all three of its future crews. The temperature had risen to 54°C but it was determined that all of the canned food on board would survive such temperatures for quite a while if necessary. Further concerns affected the medical supplies and film—it was decided that the crews would carry fresh supplies with them.

Ultimately, however, it would fall to the first crew to make repairs to the station if the entire planned program was to be carried out. Many possible solutions for both the shield and the solar array problems were put forward, but most were not prac­tical. Eventually 10 solutions were shortlisted, and after further deliberations this list was cut to two. It was decided to supply the first crew with both solutions. An improved Sun shield solution would be made ready for the second crew to install after the first crew had reported on the condition of the station. Testing of the components to be used by Conrad’s crew was carried out by Schweickart and Kerwin in the neutral buoyancy water tank at the Marshall Space Flight Center, to develop proceedures and verify that the equipment would function as anticipated. The Extra­vehicular Activities (EVAs) planned for Conrad’s crew were arguably the most complex, and the requirement to undertake them so early in the mission by a rela­tively untrained crew was greeted with nervousness by many within NASA. A simpler method for deploying a replacement temporary Sun shield was therefore devised that would enable the crew to remain inside the workshop, but for the stuck solar array there was no choice but to proceed with the planned EVA. The command module for the first crew would therefore be crammed with improvised and off-the-shelf tools to aid in the freeing of the remaining solar array.

Pete Conrad and his crew lifted off from the milkstool on Pad 39B on 25 May 1973, their destination the damaged Skylab Orbital Workshop. The rendezvous proceeded normally, and the first order of business was to fly around the workshop to carry out a visual inspection of the damage. After first docking with Skylab in order to conserve station-keeping fuel, the crew undocked to carry out a stand-up EVA. Conrad drew the command module up to the damaged solar array for a closer inspection; which revealed that a couple of metal straps were preventing the still intact array from deploying. They depressurized the command module and Paul Weitz and Joe Kerwin prepared to attempt to free the trapped wing. The procedure was for Kerwin to remain in the hatch and hold on to the legs of Weitz, who was hanging out of the hatch with a long-handled cutting tool. Every time Weitz

attempted to cut the metal straps he would inadvertently pull the command module nearer to the hull of the Skylab, which meant Conrad at the controls had to fire thrusters to prevent a collision, which in turn made Kerwin’s task difficult. It just was not going to work. The crew now attempted to dock their spacecraft with Skylab’s axial docking port again, but this time they had trouble, only completing a successful docking after they had disassembled the command module’s docking mechanism and carried out repairs. Mission Control decided that this would be a good time for the crew to have a meal and a sleep period before entering the station.

When the crew did enter Skylab the next day, they found the temperatures to be extreme, about 125°F; Conrad likened it to the engine room on an aircraft carrier. Entering the workshop in short shifts and returning to the command module to cool off, the crew set about deploying the makeshift parasol. Making use of a small scientific airlock in the wall of the workshop on the sunward-facing side, they deployed the temporary sunshade in the fashion of a chimney cleaner extending his brush by adding a new section of rod and pushing it further up the chimney. Conrad and Weitz carried out the deployment, whilst Kerwin watched their progress from the command module. Once the parasol had been fully extended, it began to flatten itself in the warmth of the Sun, and soon the temperatures in the workshop

began to drop; although it took about a week for the temperature to drop below 70 ° F. The workshop was now habitable, and the crew moved their belongings into their individual cabins and began to unpack the contents of the station in preparation for carrying out their assigned scientific duties.

Power, however, was a big problem; with only the solar arrays on the telescope mount available, Skylab had less than half the power it required. The crew would have to venture outside and attempt once more to free the trapped solar wing. Conrad and Kerwin ventured outside with the various tools that had been loaded on board their command module. One tool was a very-long-handled cutter of the type used by telephone repair men to remove branches that interfered with telegraph poles and wires. The crew had decided after their earlier inspection that this tool would be ideal to cut the metal straps that restrained the solar wing. However, when Kerwin tried to use it he found that it was impossible to place the cutting jaws precisely where he wanted them, partly owing to the length of the handles, but mainly because he was unable to get the leverage he needed for his own body in the weightless conditions. After many exhausting attempts, he noticed an attachment point on the hull and by connecting his dual tethers to this point, and one other, he discovered that he could “stand” on the hull with the tethers strained against him. This gave him the leverage and positioning that he needed, and he was able to snap first one of the restraining straps, and then the other. Almost unbelievably, the solar wing refused to deploy. Both men looked on in exasperation, until it was realized that the hinges were probably frozen and holding the wing in place. Kerwin decided to venture out into the middle of the wing and push against a rope that was tied to it, and eventually the hinges were freed and the wing began to deploy. Conrad, meanwhile, had been shot from the wing like an arrow; but his umbilical line caught him and he returned to the station hand over hand in time to see the wing fully deploy. Conrad and Kerwin re­entered the station whilst delighted ground controllers confirmed that the wing was now fully deployed and generating electricity, Skylab was saved.

Conrad and his crew could now settle into more of a standard routine, more like the one originally envisaged. They immediately discovered that Skylab was big and roomy, much larger than any spacecraft they had previously experienced. To give some idea of its size, the interior usable volume of Skylab was about 361 m3, which is a fairly meaningless number; by comparison an average semi-detached three-bed­room house has a volume of about 270 m3. That made Skylab pretty big, but bear in mind that in your three bedroom house on Earth, in normal gravity, you only get to use the floor space of that 270 m3, any space above your head is essentially wasted. In orbit, in zero-g, all of that space is habitable whether its floor, ceiling, or wall. The early Salyut stations had little more than 100m3 of space so you can see that Skylab was large for its time, and in fact its internal size would not be surpassed until the Mir space station had been fully constructed twenty-five years later.

The hydrogen tank that the crew now lived in was split into two decks, if you imagine Skylab standing upright as it was on the launch pad with the workshop at the bottom, and the docking adapter and telescope mount at the top. The very first thing we see working from the bottom of our stack, is the original oxygen tank of the Saturn rocket stage, this tank has been basically left alone, and was used to store all of the crew’s rubbish. The crew put the rubbish into the tank via an airlock connector which ran between the oxygen tank and the much larger hydrogen tank. The “bot­tom” floor of the hydrogen tank contained the crew’s individual sleeping quarters, the ward room, the bathroom, an experimental rotating chair, and the airlock for the rubbish tank, as well as a shower, a first for any manned spacecraft. Each crewman had his own sleeping compartment, with a sleeping bag hung on one wall, and storage space for personal items. Pete Conrad found that he did not like the way his sleeping bag was hung because the airflow went up his nose, so he turned the sleeping bag around; of course it’s all the same in zero gravity. The wardroom contained a table that all three crewmen could assemble around with a separate area for each of them; this allowed them to heat their food with a kind of tray to eat from. In the center of the table there was a water dispenser, both for drinking directly from, or for re­hydrating their food packs. The table also included a kind of bar stool arrangement for each man, but they found these very awkward to use as it meant that they had to conscientiously bend over the whole time, and their abdominal muscles quickly became tired. The shower, which many might think would be a very welcome addition to any spacecraft that you are going to spend a significant amount of time aboard, proved to be not as useful as hoped. The shower compartment was not a permanent glass structure that you might expect on Earth, but a collapsible enclosure to aid cleaning. In the absence of gravity the water had to be pressurized for it to “flow” from the shower head, and the water had then to be collected by means of a suction head much like a vacuum cleaner that was used to suck the water from the interior of the shower, and the astronaut. The crews found that whilst it was a pleasant experience to have this facility, it took a great deal of time to set-up, use, and clean up after, and they therefore used it less often than they otherwise might have. The bathroom was not quite such a chore to use, but the three crews did all find it a little odd that the designers had chosen to place the toilet on the wall, which meant that the crewman ended up facing the floor. In all other respects that system worked well, which was just as well, as the alternative meant reverting to the Apollo plastic bag method!

The main reason for the crew’s presence on board, of course, was to carry out scientific experiments. A great many of these were carried out on the crew themselves, to study the effects of long-term weightlessness on the human body. One of the other important roles of Skylab was to study the Sun. An entire suite of equipment had been designed for this purpose, and the crew trained extensively in its use. Once the power problems were solved, the crew were able to carry out their full schedule of Sun observations using the ATM (Apollo Telescope Mount).

An important milestone was achieved on 17 July when Conrad’s crew surpassed the 23-days-in-space mark set by the Soyuz 11 crew on board Salyut 1 in 1971. They spent their final week finishing the current experiments, stowing results for return to Earth, and getting the station ready to be unmanned for a period of time before the arrival of the next crew. Once the crew had separated from Skylab, another fly – around was carried out to photograph the condition of the station, then they fired the SPS engine to initiate the return home. The crew had completed 28 days in space, and Conrad was now the new spaceflight record-holder with over 1,179 hours in space. Years later, when asked, he would say that Skylab 2 was the mission that he was most proud of, and that when he thought about space, he always thought of Skylab and all of that room. Most people he met assumed that his mission to the moon would have been the highlight of his career, but as far as he was concerned Apollo 12 had gone by the numbers, and had been relatively routine; he would not trade it for the world, but it really had not been that exciting. Skylab was different; he and his crew had faced unknown problems, and surmounted them, and they had left the station able to continue the mission for which it had been launched, as well as achieving nearly all of the mission’s scientific objectives.

Skylab’s mission continued after the departure of the first crew. The ATM had been designed to be controllable from the ground, and therefore solar observations

continued. Unfortunately, a primary gyroscope used to control the orientation of the station failed, and observations were stopped until the next crew could arrive. It was decided to bring forward the launch of Skylab 3 so that they could replace the failed gyro, and also install an improved sunshield, as controllers feared that the temporary solution deployed by Conrad’s crew was deteriorating faster than expected.

The Skylab 3 crew consisted, as planned, of commander Alan Bean, pilot Jack Lousma, and science-pilot Owen Garriott, and their command module was almost as packed with additional items as the first crew’s had been, partly because the intention was to increase the mission duration by three days, to the originally planned 56 days. The improved sunshade was one thing, but they also carried extra film canisters, extra food, various spare parts, including a replacement set of gyros. Launch was set for 28 July 1973, and the countdown proceeded smoothly. Only Bean had flown pre­viously; Garriott and Lousma were rookies. Lousma fell asleep whilst waiting for lift­off. As he would later recall, “Just about thirty seconds before launch, you reach over to your buddies, shake their hands and wish them good luck, because their luck is going to be the same as yours!’’

Skylab 3 was launched flawlessly, and had no trouble docking with Skylab. After many checks, the crew entered the workshop to mark the first time that a space station had been reoccupied by a different crew. However, the mission had not been without some complications at this early stage. Lousma had started to suffer from some “stomach awareness”, or Space Adaption Syndrome as we now call it, shortly after reaching orbit, and later as they entered the station Bean and Garriott had also begun to suffer too. Bean had, of course, flown on Apollo 12 with no problems at all, and it caused some surprise in Mission Control when he reported feeling ill. The crew did their best to carry on with their duties, but inevitably fell behind schedule. The net effect was that Mission Control tried to give the crew additional rest time in an effort to speed their recovery, and also postponed the first planned EVA by 24 hours. Over the next couple of days, the crew slowly began to feel better and began to catch up on the schedule; however, the entire episode caused concern for mission planners, especially with the next Skylab crew—all rookies—scheduled for a longer mission.

The problems did not end there unfortunately. It had also been noticed early on that one of the thruster quads on the Apollo service module had sprung a leak, and eventually it was deactivated. The spacecraft was able to fly perfectly well with the three remaining quads. However, several days later a second quad also started to leak and had to be shut down. This still did not represent any immediate danger for the crew, as Apollo was quite capable of flying on two, or even one thruster quad, but it did cause concern that eventually all four quads might be rendered useless. NASA’s contingency planning came into its own at this point; a rescue mission had been planned for all three missions to Skylab, and it was this option that saved the mission. If there had been no possibility of a rescue mission, the Skylab 3 crew would have packed up and come home as soon as possible, whilst the two remaining quads were still operational. But the possibility of flying a rescue command module meant that both the crew and Mission Control could afford to wait and see. In the meantime, the rescue crew of Vance Brand and Don Lind rehearsed in the simulators and their modified command module was readied for flight. The engineers on the ground were able to determine that the leaks in the two thrusters were unrelated, and that there was nothing to suggest a systematic fault. The rescue crew were stood down, although they did spend time simulating the Skylab 3 return with only two working thrusters. Lind would later remark that he had effectively talked himself out of his first flight by showing that the Skylab 3 crew could return safely without the need for a rescue flight.

After these dramas, life settled into a gentler routine for the Skylab crew. There were a few equipment malfunctions that had to be attended to, but on the whole the rest of mission was quiet. Garriott and Lousma installed the improved sunshield during an EVA 10 days into the mission. The same pair also retrieved film cassettes from the ATM later in the mission, and later still Bean and Garriott retrieved more film cassettes and also retrieved a sample of the new parasol to determine its con­dition after a month’s exposure. When the time came for the crew to leave the station, they had more than completed their objectives, and after the initial problems with space sickness had subsided, had consistently been ahead of the flight plan, always asking for more work, and by the end of the mission they had in fact achieved over 150% of their targeted work. Whilst this was a fantastic achievement, it would not bode well for the crew that was to succeed them.

The crew for the third and final Skylab mission broke from Deke Slayton’s usual rules of crew selection; they were all rookies. Their mission had changed somewhat, too. A comet had been discovered that would approach the Sun toward the end of 1973, and the launch of the third crew was delayed from its original October launch date until November so that they could carry out observations using Skylab’s ATM and other instruments. The booster for the last Skylab mission had been sitting on the pad for some time, as it had originally been rolled out to serve as booster for the Skylab rescue mission; when this mission was stood down, the booster became the Skylab 4 launch vehicle. However, just five days from launch a routine inspection crew discovered cracks on the stabilizing fins of the first stage. Perhaps this was not surprising, as this stage had been manufactured over seven years earlier, but clearly it

could not be launched in this condition. It was decided to replace the fins on the pad, which would take about a week. The crew faced a tight squeeze in their Apollo Command Module due to it being packed with additional items for the long mission ahead, most of it food to allow the length of the mission to be extended from the planned 70 days to 84 days if all else was well. The launch itself was routine and seven hours later the crew sighted Skylab and prepared to dock—which they had some difficulty with initially, but managed at the third attempt.

With the experiences of Al Bean’s crew very much in mind, Mission Control had ordered the astronauts to take more precautions against space sickness in order to prevent disruption to the early mission flight plan, and they took anti-sickness pills as soon as they reached orbit. It was also decided that the crew would have a sleep period before entering the station for the first time. Unfortunately, it was swiftly proved that this approach did not help, as Bill Pogue was overcome with nausea almost as soon as the rest period began, and relieved himself of his last meal. The crew made the first mistake of the mission when they decided not to mention Pogue’s symptoms to Mission Control. Confident that he would feel better before they entered the lab for the first time they simply explained that he had not felt hungry and had left most his last meal uneaten. This plan might have worked if it were not for the on-board automatic taping system which recorded the entire conversation and relayed it later to the ground, and most importantly to Chief Astronaut Alan Shepard. As a result Shepard talked directly to the crew commander, Gerry Carr, and voiced his opinion on what he called “a fairly serious error in judgement”. Carr realized the error of his ways and put his hands up and agreed that “it was a dumb decision”.

Despite the best efforts of the mission planners, Pogue’s sickness would impact the early activation of the station by limiting his participation with the rest of the crew. In fact, the planners seemed to assume that this crew could pick up at the same pace as Bean’s had left off, which ignored the fact that it took Bean’s crew several days to get near that pace of work. The planners also seemed to assume that procedures in space took the same amount of time as taken during training on the ground, and as hard as the crew tried to keep pace, they simply could not, and fell further behind the timeline set by the ground controllers. Even worse, the planners on the ground did not seem to realize that they were making things worse; they even added extra tasks to the crew’s day, causing them to fall even further behind, and consequently start to believe that they were not doing a good enough job. On the seventh day of the mission, Pogue and Ed Gibson carried out a planned EVA to replace film cartridges successfully, but even then the tired crew left some stowing away tasks until the next day. All in all, the first three weeks or so were very difficult. But things began to improve as the crew realized how to make things better, and better communicate those thoughts to the controllers on the ground. This was about the same period of time that Al Bean’s crew had taken to reach their peak efficiency, but this fact was apparently forgotten by the mission planners, who seemed to assume that the new crew could immediately start where the previous crew had left off. The crew desperately tried to remain on the timeline, and explain the problems to those on the ground, but their pleas went unheeded. The mission planners, for their part, always felt that the crew were about to reach their best performance level, and were therefore reluctant to reduce the workloads. After all, this was the last chance for these scientific experiments to be flown and NASA wanted to take advantage of every waking moment. It all came to a head after the crew had been in orbit for about six weeks. During a call with the crew’s boss, Deke Slayton, all of the problems were voiced and discussed, the ground were persuaded to ease off on the workload, and also leave some of the scheduling to the crew rather than providing a daily minute-by­minute task list. This meant that the crew felt more in charge of their activity, and were able to follow a more “normal” day. The rest of the mission proceeded at a similar pace to the previous ones, and by the end of January 1974 the crew were making preparations to return home. The orbit of Skylab was raised slightly with a firing of RCS jets on the Apollo service module, in the hope that this might allow Skylab to survive for longer, and perhaps be visited again before its expected orbital decay in 1981 or 1982. The Skylab 4 crew landed about 5 hours after undocking having spent a total of 84 days and 1 hour in orbit.

The possibility of a Skylab revisit and re-boost mission would now be left to the space shuttle, which at this stage did not exist, so a choice had to be made between trying to preserve the station for some future visit by Apollo CSM or the space shuttle, or a mission to send a crew in Apollo to carry out a controlled re-entry burn to send Skylab to its destruction. There were some risks attached to the latter, as it involved the docked CSM firing its service module engine until Skylab had almost reached entry interface, which meant that a prompt undocking was a very important action; if the docking latches failed in some way the crew would follow Skylab to destruction! In part due to these risks, it had been decided to boost Skylab to a higher orbit before the final crew left, effectively deferring the decision until the early 1980s. Once the space shuttle program was underway, it was tentatively planned that during its third flight the shuttle would rendezvous with Skylab and attach a booster rocket to the docking port, at which time it would be decided whether to boost the station to a higher orbit once more, or send it to the bottom of the Pacific Ocean. Ironically, Jack Lousma of Skylab 3 was assigned to pilot the shuttle’s third mission, and revisit his old home. In the end, two factors decided Skylab’s fate. The first was the protracted development of the shuttle, it became clear over time that the shuttle would simply not be ready in time to save the orbiting station, especially as it’s orbit was deteriorating faster than expected owing to increased solar activity inflating the upper atmosphere and causing increased drag. Skylab would have to be left to make an uncontrolled re-entry sometime in 1979, and it seemed every nation in the world was worried that it would fall on them. Shortly before its crash to Earth, it was determined that Australia was the most likely target, and at least 25 tons of various parts of the station were predicted to survive the re-entry process. In the event, several parts did survive, and a young Australian claimed the $10,000 prize that a U. S. newspaper had offered as reward for any genuine Skylab parts. The largest items found were a door from one of the film vaults, and some oxygen and nitrogen tanks, and these along with various museum pieces like the back-up Skylab are all that remain of the United States’ first space station.

Was Skylab a success? The answer is both yes and no. Yes, because NASA successfully carried out a great deal of science during the three manned periods, and even during the unmanned intervals as well. For an agency that had no real experience of carrying out scientific experiments, other than those on the surface of the moon, and none at all over long periods of time, it was a very successful project. Detailed photography and data about the Sun was collected—enough to keep researchers busy for some years, human medical experiments, materials processing, and more besides, were all carried out with precision and accuracy by the various crews. On the other hand, Skylab was not a success, because the mission planners in particular seemed unable to learn from the experiences of previous crews. The work schedule for all of the crews was always unrealistic. It was an easy mistake to make on your first space station project; the Soviets had experienced similar problems after all with the early Salyut mission. Amazingly, NASA would be doomed to repeat these mistakes in years to come on board Mir and the International Space Station.

In a 1946 summary of his work during World War II, Wernher von Braun prophesied the construction of space stations in orbit. The design, which owed a great deal to the earlier work of Noordung, consisted of a toroidal station spun to provide artificial gravity. Von Braun elaborated on this initial design at the First Symposium on Space Flight on 12 October 1951 hosted by the Hayden Planetarium in New York City. The design was popularised in 1953 in a series in Colliers magazine, illustrated with a gorgeous painting by Chesley Bonestell.

1948—THE BRITISH INTERPLANETARY SOCIETY STATION—H. E. ROSS

In a paper presented to the British Interplanetary Society (BIS), and reprinted in the Journal of the BIS in 1949, H. E. Ross described a manned satellite station in Earth orbit that would serve as an astronomical, zero-gravity, and vacuum research labora­tory, and also serve as a way-station for the exploration of the moon. His suggested design comprised a circular structure that housed the crew of the space laboratory

(numbering 24 specialists and support personnel) as well as telescopes and research equipment. The station, he suggested, could be resupplied with oxygen and other life – support essentials by supply ships launched every three months.

Salyut 1 had not been a failure; the death of the returning crew was tragic, but the space station itself had been blameless. The Soviet space organization was keen to launch another as soon as possible. Of course they had to wait until the Soyuz ferry vehicle was ready to resume flight. Arguments raged over the best way to achieve a safer Soyuz design, Chief Designer Vasily Mishin argued that simply adding space – suits to the capsule was not the right answer, it limited the crew to two and seriously reduced the cargo the ferry could carry to and from orbit in addition to the crew. However, he was overruled by the Secretary of the Central Committee, Dmitri Ustinov, who was absolutely determined that no cosmonaut would be launched into orbit without a spacesuit ever again. Mishin continued to argue that reliability of the systems was the best method of ensuring the safety of the crew, but he was told in no uncertain terms that Ustinov’s word was final, and that pressure suits were to be installed. This required a new version of the Soyuz spacecraft that would only have an orbital lifetime of two days. This was necessary as the solar arrays of the previous version had to be removed to save weight, and the on-board batteries would only last for that limited time.

After the “civilian’’ first station, it had been decided to introduce the first pure Almaz design, designated OPS-1, albeit using the Soyuz craft as the ferry instead of the TKS. The Almaz design also differed from the first Salyut in that its docking port was at the rear of the station. OPS-1 made it to Baikonur in the midst of the harsh winter of January 1973, and during the next 90 days military testers and civilian specialists prepared it for launch. The OPS-1 blasted off into orbit on 3 April 1973. Since the authorities did not want to disclose the existence of two space station projects in the USSR, and particularly, to reveal the development of the military Almaz, the OPS-1 was announced as Salyut 2 upon reaching orbit. It was given the Salyut name to disguise its military configuration, but it was different to the space station that had preceded it. It was several meters shorter, but weighed about a ton and a half more. In the center of its living compartment a huge camera was installed

in the “floor” and the station had a much higher level of automation to reflect the reduction in the Soyuz crew.

Unfortunately this new station did not last long enough for any crew to board it, and perhaps this was just as well, because 13 days after launch an electrical fire in the propulsion unit spread to the main compartment, explosively decompressing the station and sending it spinning out of control until it broke up. The official investiga­tion concluded that as a result of a faulty welding, one of the lines in the station’s propulsion system had burst during an engine firing and the plume of flame had burned through a pressurized hull. However, future findings were to cast doubt on this theory. Careful analysis of fragments detected in orbit, showed that three days after the launch of the OPS-1 the upper stage of the Proton rocket that had delivered the station apparently exploded as a result of pressure changes in its tanks resulting from overheating. The stage carried about one tonne of unspent propellant, and the explosion created a cloud of debris in the proximity of the station. The speed of some debris differed from that of OPS-1 by as much as 300 ms_1. Eight days later, a piece of this orbital junk apparently hit the station. However, despite all this secrecy and the attempt to cover up the military nature of the station, western observers almost instantly managed to discern the military nature of the new spacecraft. An article appeared in the September 1973 issue of Aviation Week, which read, “Soviet pench­ant for secrecy within its own space program has lead to a widespread, but erroneous, belief that a Salyut spacecraft failed while in orbit. The spacecraft, which the Soviet press and information agencies called a Salyut, was launched Apr. 3 and apparently suffered a catastrophic failure on Apr. 14. However, the spacecraft transmitted on a different frequency than previous Salyuts and now is believed to have been a different spacecraft. The reports initially issued by the Soviets apparently were incorrect because of an attempt to keep secret the actual nature of the spacecraft. Telemetry transmissions from the spacecraft were similar to those monitored earlier from Soviet reconnaissance satellites.” Although the Almaz name was not known in the West for many more years, these stations had become identified in the West as “military Salyuts”.

Undeterred, the Soviets launched another station only a month later. This was not an Almaz, but the third station in the DOS series. DOS-3 carried several improvements over the earlier configuration. It had improved solar arrays in an effort to double the overall lifetime of the station from the 90 days of the two previous stations. In most other respects, however, the station was basically the same, although more thought had been given to automating systems to accommodate the reduced crew of two. Unfortunately, due to errors in its flight control system, and while out of the range of ground control, the station fired its orbit-correction engines until it ran its tanks dry, and a week later re-entered the Earth’s atmosphere. Since the station had reached orbit, and therefore been tracked by western ground stations, the Soviets had to acknowledge its existence but, in a effort not to give anything away, designated it Cosmos 557 as a form of disguise.

The Soviets finally enjoyed some success with the launch of Salyut 3, a station of the Almaz design, in June 1974. The OPS-2 space station really was a reconnaissance platform, for it housed a massive 6-meter camera in its main compartment and had a capsule for the high-resolution film to be returned to Earth independently of the crew. In all 14 cameras were to be used on board. The other notable feature of this station was the modified aircraft machine gun that was mounted near the front port for station defence! In order to point it at the target the crew had to change the attitude of the entire station.

When the Salyut 3 station was launched a small group of teachers and school children in Northamptonshire, England, were glued to their radio receivers. The group would later become known simply as the Kettering Group, but for now physics teacher Geoffrey Perry and some of the pupils from Kettering Grammar/Boys School

had no particular name. They had for some years been following the satellite launches from both the U. S.A. and the Soviet Union by means of radio receivers within the school. He and his team of teachers and pupils had amassed a great deal of knowl­edge, particularly about Soviet satellites, since the launch of Sputnik 2 in 1957. Mr. Perry correctly identified launches from a site other than Baikonur in 1966, which would be later known as Plesetsk, and was also the first to record evidence of the first unmanned Soyuz test after the tragedy of Soyuz 1. Now with the launch of Salyut 3, they hoped to positively identify the station for themselves. But when they listened to the same channels that they had listened to previously for manned Soyuz

missions and the Salyut 1 station, they could hear nothing. The same thing had occurred the previous year with Salyut 2, and they wondered why this could be. It was later determined, with the help of other radio amateurs, that the station was using a frequency only usually used by military reconnaissance satellites. Although it was immediately apparent that this change of frequency meant that the station was military in nature, it was clear that it was being operated differently than the previous Salyut station. They hoped to confirm their hypothesis when the inevitable Soyuz spacecraft was launched to dock with the new station.

The crew of Soyuz 14 were Pavel Popovich and Yuri Artyukhin, both military officers, who were launched on 3 July 1974 and docked later that same day.

According to Popovich, the on-board automated rendezvous system delivered the Soyuz spacecraft only 600 m from the station and from a distance of 100 m the crew switched to manual control. Popovich remembers taking off his spacesuit gloves, (unpressurizing his suit, as a result) in order to make it easier to control the craft. The Kettering Group were able to identify for themselves that the Soyuz was only manned by two cosmonauts, and determined the identity of its commander, and they made a press announcement to the world through Reuters before the Soviet Union had even officially announced the launch. By comparison the U. S. CIA had no such detailed information; in a National Intelligence Estimate dated December 1973 they seemed only to be aware of the civilian Salyut program, and gave no indication that they had any information regarding the military Almaz program.

Popovich and Artyukhin entered the OPS-2, having docked at the rear, on 4 July 1974 and spent 15 days on board. According to official sources, the “remote-sensing

equipment” was activated on 9 July, followed by several days of photography of the “Earth surface”. Central Asia was among officially disclosed targets of the station’s cameras. Western sources also say a set of targets laid out near Tyuratam was photographed to test the capabilities of the surveillance hardware. Several times during the mission, an on-board alarm system woke up the crew; however, it proved to be false. During the flight, the cosmonauts reportedly checked the systems on board, adjusted the temperature inside the station, moved some ventilators and completed other housekeeping chores. They also reloaded the station’s on-board cameras and placed exposed film into the space station’s return-to-Earth capsule.

The second crew consisted of commander Genadi Sarafanov and flight engineer Lev Demin, and they were launched on board the Soyuz 15 spacecraft on 26 August 1974. However, problems with the rendezvous system on board the Soyuz during the approach to the station forced officials to cancel the docking attempt. The spacecraft returned to Earth after a two-day flight, the limit of the Soyuz’s orbital endurance, and was forced to land under night-time conditions. Typically for the period, official sources reported only that the Soyuz 15 crew “tested various rendezvous modes during its mission’’.

Two decades later, the official history of RKK Energia revealed that when Soyuz 15 reached a distance of 300 m from the station, the Igla (“Needle”) rendezvous system, failed to switch to the final-approach mode and instead started implementing a sequence that would normally be executed at a range of 3 km from the station. On commands from the Igla, the Soyuz fired its engines, accelerating itself in the direction of the station. The relative speed of Soyuz 15 to the OPS-2 reached 72kmh-1, zooming by the station at a distance of 40 m. As the crew failed to realize the problem (and to shut down the Igla), the rendezvous system attempted to re­acquire radio-contact with the target and sent Soyuz 15 to the station twice more each time narrowly avoiding a collision. By the time ground control commanded the deactivation of the Igla, the crew only had enough propellant for the descent back to Earth.

Due to lengthy modifications in the wake of Soyuz 15’s rendezvous problems, no further expeditions to Salyut 3 could be staged. The return-to-Earth capsule was jettisoned from the OPS-2 on 23 September 1974 and successfully recovered on Earth, and the station was de-orbited on 24 January 1975 over the Pacific Ocean.

According to official Soviet sources, the seven-month flight of Salyut 3 exceeded more than twice the originally planned flight duration. Soviet publications also disclosed that Salyut 3 was the first space station to maintain constant orientation relative to the Earth’s surface. To achieve that, as many as 500,000 firings of the attitude control thrusters had been performed. This fact also hinted to Western observers that Salyut 3 had perhaps carried out a reconnaissance mission.

Years later it was revealed that shortly before de-orbiting OPS-2, ground con­trollers commanded the “self-defence” gun on board the station to fire. According to Igor Afanasiev, an expert on the history of space technology, firings were conducted in the direction opposite to the station’s velocity vector, in order to shorten the “orbital life’’ of the cannon’s shells. A total of three firings were conducted.

In “Analysis of Orbital Systems,” a paper read at the fifth congress of the International Astronautical Federation in Innsbruck, Austria, Krafft Ehricke described an orbital station. Arguing that a very large space station was neither necessary nor desirable, Ehricke postulated a four-man design that might serve a number of different purposes, depending upon its altitude and orbital inclination. He suggested that such a station might be used for a variety of scientific research, for orbital reconnaissance, as an observation platform, and as a launch site for more distant space ventures. Later in 1958 Ehricke outlined the design for this station and called it Outpost. It would consist of an empty Atlas rocket equipped only with a pair of two-man gliders to serve as lifeboats, and could be powered by a nuclear reactor. Three further launches by Atlas-Centaur boosters would carry all of the remaining

The 1948 BIS Station

equipment required by the station. The crews would also be launched by Atlas – Centaur. Future plans called for Outpost II and III, each of which would be bigger than the last, consisting of clustered Atlas boosters, with the whole station spinning to provide artificial gravity to the occupants in either end.

Salyut 4 differed from Salyut 1, the previous successful DOS design, by having three sets of solar arrays, just as the doomed Cosmos 557 had. It also included some additions for crew comfort, including a table for the crew to eat at which supplied hot and cold water for rehydrating their food packs. The navigation system for the station was now semi-automatic, to allow the crew more time for experimentation. It was launched on 26 December 1974, and was followed on 11 January 1975 by Soyuz 17 with a crew of two, Alexei Gubarev and Georgi Grechko, both making their first space flights.

Their docking was achieved effortlessly, and they soon settled into the mission, working for six days a week, with a day off to spend largely as they wished. Their enthusiasm for their work was such that they worked longer hours than anticipated, and also ate more than planned, which had to be controlled as there were only so many supplies on board. Eventually they were told to slow down and take more time off, which they reluctantly did. The Soviets were still working to discover the best compromise between work and rest for the cosmonauts’ working week. The crew returned to Earth on the 7 February after 30 days in orbit, a new Soviet record of endurance, and were found to be in good physical and mental shape. However, it was decided that the exercise regime for future crews would be stepped up slightly, especially in the later stages of the mission to ensure that they were in the best condition for re-entry and adaptation to Earth’s gravity.

The launch of Soyuz 18 on 5 April was rather more dramatic, and once again the Soviets failed to get a mission to a space station. A fault with the separation of the main booster stage caused the abort tower to be used for the first time in manned spaceflight, causing the crew, Vasili Lazarev and Oleg Makarov a very uncomfortable 15-g ride before the capsule landed in snow. The next launch attempt on 24 May was also called Soyuz 18, and the previous failed flight simply referred to as “the 5th April anomaly’’. This crew, Pyotr Klimuk and Vitali Sevastyanov, reached orbit successfully, and docked with Salyut 4. Their task was essentially to carry on the

work started by the previous crew, but this time the Soviets tried to schedule the workload more logically. They would work for several days on one type of experi­ment before moving on to the next; a significant step forward. Of course, there was also maintenance work on the station to be carried out between scientific experi­ments, but again experience from previous missions was paying off, as items such as filters, pumps etc., had been made much easier to replace and service than previous designs, cutting down on time and frustration.

A new mission was launched on 15 July 1975. Although this mission did not involve Salyut 4, it did signify the first co-operation between the Soviet Union and the United States of America: ASTP, or Apollo-Soyuz Test Project. Discussions for such a mission had been taking place for several years, as mentioned in an earlier chapter, but the options were soon narrowed down to one: the docking of an Apollo Com­mand and Service Module with a Soyuz spacecraft. On 24 May 1972, U. S. President Richard Nixon, and Soviet Chairman Alexei Kosygin, signed the agreement that would make ASTP a reality. It was part of a much larger agreement that covered all manner of scientific co-operation, including space flight. Despite the air of co­operation, there remained “discussions” about various aspects of the mission. Which spacecraft would launch first? NASA assumed that Apollo with its longer mission duration would be the first to launch. That way if Soyuz was delayed for any reason, Apollo could simply wait until it arrived. The Soviets disagreed, stating that they would launch first, and wait for Apollo; if Apollo were delayed, they would launch a second Soyuz if necessary. This came as something of a surprise to NASA mission planners, as they had not previously heard anything about a second Soyuz being prepared for this mission. The actual docking posed even more problems, both technical and political. What form would the docking mechanism take? Both nations so far had used a male and female docking mechanism; which nation would take which role? The Soviets were rather more chauvinistic in this area, not wishing to take the “lesser” role of the female as they saw it. It was finally agreed that the docking system would be an androgynous one that equalized the two nations, but this also presented another problem. Which spacecraft would be the active (moving) ship, and which would wait (stationary) for the docking? The Apollo was clearly the more maneuvrable spacecraft, and so the Soyuz would have to wait to be docked with by the Apollo. Unfortunately, the problems did not end there. The atmospheres of the two spacecraft were very different. Apollo’s atmosphere consisted of 100% oxygen at a pressure of 0.34 atmosphere, whilst the Soyuz was an oxygen/nitrogen mix at 1.0 atmosphere. Clearly, it would be possible to simply float from one spacecraft to the other without suffering from the bends, so the docking mechanism would also have to double up as an airlock. With modifications to both spacecraft to allow the lowering of cabin pressure to make the transfer between the two craft quicker achieved, the major technical problems had been overcome. The first of the two crews were announced in 1973; the U. S. crew would consist of commander Tom Stafford who had previously commanded Apollo 10 and Gemini 9, and flown as pilot on Gemini 6. The Command Module Pilot would be Vance Brand, who would be making his first space flight after backing up the last two Skylab crews. The third crewmember had been waiting for a flight for a long time, after years of selecting other astronauts for their missions Deke Slayton, a member of the original Mercury astronaut group, would finally make it into orbit. The Soviets followed with their own crew announce­ment a few months later. This was a first, as crews for Soviet space flights had never been announced in advance before. The commander of Soyuz 19 would be Alexei Leonov, who we know all about from his travails during the crew selection for Soyuz 11. His flight engineer would be Valeri Kubasov, who had been removed from the Soyuz 11 crew for medical reasons, but was long since recovered. He had flown

previously on Soyuz 5 and had spent time on Salyut 6; in fact he had more flight experience than his commander.

With the crews announced, training for the flight could now begin. Learning each other’s language proved to be the most difficult task for both crews; something that would not change much over the coming years. The problem did not end with the crews of the spacecraft, the ground controllers and technical experts also needed to get up to speed on their counterparts’ language, a task that is particularly difficult where technical jargon is concerned.

Apollo-Soyuz finally got underway when Soyuz 19 was launched on 15 July 1975. With Soyuz safely established in orbit, Apollo was launched to give chase. Almost two days later, the two spacecraft docked without difficulty. The two crews spent 47 hours docked together, with members of each crew visiting the other’s spacecraft. Mission rules dictated that neither vehicle would be left unmanned at any time. After the docked phase of the mission Soyuz 19 returned to Earth almost immediately even though this Soyuz was equipped with solar panels like previous versions, and could stay in space for longer than its space station specific counter­parts. Apollo stayed in orbit for a further three days to conduct experiments that

would have to last NASA for a while, this being the last U. S. manned mission until the space shuttle was ready to fly, at this time expected in 1979.

It has been suggested that ASTP was little more than a political show, but this opinion sells the program short. In truth the idea may have been born out of political needs by both the U. S. and the Soviet Union, but that fails to take into account that many of the people that worked on this mission from crews to support staff and technical designers from both countries would later work together again on Shuttle – Mir, and ultimately the International Space Station (ISS). Relationships that were forged during ASTP would endure to smooth new relationships in the 1990s. It has been said that neither side learned very much; the U. S. engineers say that most Soviet equipment was Gemini era to them. But both countries did learn that it was possible to work together, and in the longer run that was sure to be worth something.

Meanwhile the crew of Salyut 4 continued their mission for a few more days before they too returned to Earth on 26 July, after 63 days in orbit. Before their departure they fired the engines of Soyuz 18 to raise Salyut 4’s orbit. This was the first time that such a maneuvre had taken place, previous orbit-boosts had been under­taken using the stations own propulsion. Upon their return the crew walked from their capsule to the medical tent, obviously in better physical condition than previous crews had been. Their mission had paved the way for longer duration flights, possibly involving rotating crews on a new space station. But Salyut 4’s mission was not over. Soyuz 20 was launched on 17 November 1975, and unusually for such a designation it carried no crew. It followed a different flight profile than usual, docking with Salyut 4 after two days rather than the one day that had been flown by manned up until now. Once docked, Soyuz 20 remained powered down until the end of February 1976. It later became apparent that this mission was a test of the flight profile and duration of an unmanned cargo craft. Once the craft had returned to Earth, examinations of its systems led Soviet engineers to place a 90-day limit on the amount of time that a Soyuz could safely spend in space.

Salyut 4 had been a great step forward for the Soviet space station program, after the difficulties of its predecessors, and had proved the procedures and technology that would be needed for the next generation of stations.

The next space station was Salyut 5, and it was launched on 22 June 1976. It quickly became apparent from the telemetry that this was another Almaz reconnaissance platform, identical to Salyut 3, but without the machine gun. An all-military crew of Boris Volynov and Vitali Zholobov was launched on Soyuz 21 two weeks later. The crew carried out some scientific experiments, but their primary mission seemed to involve observations of a military exercise that was underway in Siberia. They seemed set for a fairly long-duration mission, and indeed Soviet radio had reported on 19 August that solar radiation levels were such that the crew would be able to carry out a “prolonged flight’’, but five days later the same radio station reported that the crew were in the process of returning home. When they clambered out of the capsule after a night landing, it became evident that they were suffering from the effects of their mission, most likely because they had not started their pre­return exercise regime. All evidence seemed to point to the fact that the crew had returned much earlier than planned; but why? There were several suggestions, but the most likely seemed to be that the station’s atmosphere had somehow become con­taminated causing the crew to abandon ship. One speculation in the West was that one or both crewmembers had suffered mental or physical problems that forced their return. It was also suggested that Zholobov in particular had suffered debilitating homesickness, and as a result had not followed his exercise regime. It has since come to light that perhaps the two crewmembers did not get along, and perhaps their hostility got to the point that returning them to Earth was the only option before physical harm was caused. Whatever the reason, Salyut 5’s first manned mission had been abandoned early, and a crew needed to return as soon as possible to carry on the work. The next flight, that of Soyuz 22, made use of the back-up vehicle from the ASTP mission, and was not a flight to Salyut 5. Soyuz 22 was a week-long flight that concentrated on Earth photography using a special East German built camera. The fact that the next crew to visit Salyut 5 was launched within 2 months of the landing of the previous one, suggested that not too much could have been wrong with the station. The crew of Vyacheslav Zudov and Valeri Rozhdestvensky were to check on the condition of the station, and carry on with the experiments that were still left on board. However, all was not to go smoothly. The mission of Soyuz 23 on 14 October proved to be dramatic. The automatic rendezvous system malfunctioned almost as soon as it reached orbit, and for some reason not made clear by Soviet officials the crew did not attempt a manual approach and docking, but waited for the first opportunity to land. When the landing attempt came, things began to go wrong. After re-entry, the capsule descended on its parachute in the darkness, but was blown off course by a blizzard and it landed in Lake Tengiz. This was not in itself a problem as the Soyuz had been designed to land in water if necessary. Although the capsule landed in relatively shallow water, it was at least 5 miles from the nearest shore, and the water was freezing. Recovery by boat was therefore impossible, and helicopters could not locate the spacecraft as thick fog engulfed the area. The crew were forced to spend a very cold night in the capsule, which by now had no power reserves, and therefore no heating. At first light, the fog had cleared sufficiently to allow helicopters to attach lines to drag it to shore and end the exhausted crew’s ordeal. As it was, no real damage was done, but it is worth reflecting on what might have happened to a more weakened crew that had perhaps spent months in orbit, or been forced to come home early…

Viktor Gorbatko and Yuri Galzgov were launched on 7 February 1977 on Soyuz 24 for what would prove to be a short mission. Again when an automatic docking was attempted the system failed, but on this occasion a manual docking was attempted and achieved. The crew entered the station wearing breathing apparatus, but it did not take long to determine that the air was clear. Whether this procedure was really necessary, only the Soviet space officials know. However, the crew did take the opportunity to test a new procedure to clear the station’s atmosphere of any potential contaminants. They had brought some equipment with them that would allow the existing atmosphere to be vented and replaced with fresh supplies of air stored on board. Basically, the old air was allowed to leak out of one end of the station whilst at the same time fresh air was pumped in at the other end. Interestingly, the crew remained on board the station whilst this procedure was carried out, rather than retreating the Soyuz as one might expect. Shortly after this test, the crew began to prepare to come home, packing up their experiments as well as those left behind by the Soyuz 21 crew. The combined equipment and experiments were far more than the Soyuz could return by itself, so use was made of Salyut 5’s own descent capsule, designed for just such a purpose; it would return to Earth a day after the crew. The station had been left in a good state of repair, and Anatoli Berezovoi and Mikhail Lisun were already in training to attempt an unprecedented third period of occu­pancy, but due to the run of ill-luck the Soyuz spacecraft that had been allocated to the Salyut 5 programme had all been used, and there simply was not the budget nor the time to build a new Soyuz during the remaining lifetime of Salyut 5. Soyuz 24, therefore, became the last mission to a military space station. Salyut 5 re-entered the atmosphere on 8 August 1977 when all of its remaining fuel had been depleted, and it was clear that it would host no more missions.