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5.1. Skylab
Since the earliest days of the NASA space program concepts for a space station were studied. They all failed, however, since there was no way of getting such a station into orbit. As the powerful Saturn V rockets were invented in the mid-Sixties for the Apollo program Skylab initially called the "Apollo Applications Program", was born. Leftover Apollo hardware was should be used to male longer stays of astronauts in space possible.
At first there were two concepts for the Skylab mission. The concept of the "wet" workshop was to launch one of the weaker Saturn IV-B rockets and then vent and refurbish its upper stage in space. The second concept that was later realized was the "dry" workshop.
According to the plan a Saturn IV-B upper stage was modified on ground. It was divided into two levels. The "lower" one served as the astronaut's living quarters. It had three bedrooms, a dining table, a work area, as well as, a bathroom and a shower. In the "upper" level there was a storage room and a large space for experiments.
The largest piece of equipment was the Apollo Telescope Mount (ATM). It was attached to the end of the cylindrical workshop. Its purpose was to study the sun without any atmospheric interference.
Furthermore, Skylab had an airlock module for space-walks. Space-walks were not only required to do repairs but also to change the film in the ATM and to conduct other experiments.
Skylab was launched into space by a Saturn V rocket on May 14, 1973. The crew was scheduled to follow the next day but Skylab was damaged during the start. The combined meteorite shield and sunshade was torn loose and took one of the two solar arrays with it. Ten days later a fix was worked out and the astronauts were able to go on the first of three skylab missions.
The three man crew failed had to complete the repairs as fast as possible since the missing of the sunshade caused high temperatures in the station. These conditions could have spoiled the food for the astronauts and the sensitive film material for the ATM. They succeeded in setting up a parasol as a replacement for the sunshade but failed to deploy the second solar panel which was also damaged. After two weeks the repair was finally completed so that Skylab was provided with energy. After one month the first Skylab mission was competed. Two more missions of two and three months in duration followed. Until today, Skylab 4 is the longest mission ever carried out by a U.S. astronaut. It lasted 84 days. Between the missions the space station was deactivated. On July 11, 1979 the empty Skylab station burned up in the atmosphere.
The Skylab missions provided weather scientists with some valuable data. By photographing targets on the sun and evaluating weather conditions on Earth some valuable solar orientated material was obtained. The final crew also made observations of he Comet Kohoutek that was coincidentally passing Earth. The astronauts carried out lots of other experiments. For example they found out that spiders were also able to spin webs in the state of weightlessness.
5.2. Apollo-Soyuz
Apollo-Soyuz was the last mission of the Apollo era. It was less a technical matter than it was a political one. In 1972 U.S. President Nixon and the Soviet leader Kosygin initiated the program. It was a symbol for the goodwill between the two superpowers.
American and Soviet scientists had to grant each other inside into their respective programs so that a common docking system could be designed. In preparation of the flight Soviet cosmonauts were practicing at Johnson space center, and the American crew did the same in Moscow. Flight controllers from both nations also conducted joint simulations.
Apollo 18 and Soyuz 19 left Earth within seven-and-a-half hours on July 15, 1975. Two days later Thomas P. Stafford and Alexei Leonov exchanged handshakes. The two space ships remained linked for 44 hours. During that time they ate together, exchanged gifts and flags and paid visits to each other's ships. They also conducted further docking maneuvers in which the Soyuz took over the role of the active ship. The Soviets spent five days in space. The Americans concluded their trip after nine days.
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