Space Station
In the wake of the successful American moon landings of the late 1960s and early 1970s, the Soviet Union moved to pioneer manned space stations ahead of the Americans. They launched the first such station, Salyut 1, in April 1971, followed by its first crew--Georgi T. Dobrovolsky (1928-1971), Viktor I. Patsayev (1933-1971) and Vladislav N. Volkov (1935-1971)--aboard the Soyuz 24 in June.
Salyut was constructed from four cylinders of different diameters. At the forward end was a docking port and transfer compartment linking the station with the Soyuz 24 ferry craft. Soyuz had a set of solar panels to collect energy for the station's power. Its length was 47 feet (14.3 m), and its largest diameter was 13 feet (4 m). The crew of the Salyut carried out astronomical research, plant growth experiments, and earth observations. Unfortunately, the mission ended in tragedy. As the crew headed back to earth, the seal of their Soyuz capsule broke and, without pressurized space suits, the three cosmonauts died instantly.
The United States had also been planning a space station and, following the initial flight of Salyut , hurried the construction of their vessel, called Skylab. Perhaps wisely, engineers decided not to start from scratch but rather to use the shell of an Apollo rocket tank as a "skeleton." Skylab was a two-story complex with enough room for three men. The bottom section consisted of a ward room, sleep compartments, and a washroom or toilet. The upper deck contained a spacious workshop for the astronauts to carry out their assignments. It had about the same space as a small three-bedroom house. Large solar panels similar to those found on Salyut powered the station, and a thin aluminum shield protected against micrometeorites and excessive solar heat.
Soon after launch on May 14, 1973, Skylab encountered trouble. Part of the shield tore off, carrying with it one of the solar panels. The station was now seriously underpowered and was vulnerable to overheating from the sun. Eleven days later, a three-man crew was launched to meet the station. They first had to work outside the station to repair the damage to the solar panel and to deploy a hastily engineered sun shade. They were then able to carry out their original mission. For the next 28 days they observed the sun, photographed the earth, and carried out biomedical experiments.
The second mission to Skylab, launched in July 1973, was also successful. The crew conducted a large group of experiments in biology, space medicine, solar physics, and astrophysics over a period of 59 days.
The final crew, which boarded Skylab in November the same year, broke the records of the previous two flights. The astronauts spent a great deal of time on research (including observation of a solar flare and a comet) and performed physical exercise on a stationary bicycle and portable treadmill. After 84 days in space, the astronauts remained fairly healthy.
In 1979, Skylab met its fate. As its orbit decayed, plans were made for the United States' new space shuttle to attach a booster rocket to the Skylab, carrying it to a higher orbit. But before the shuttle was ready, Skylab plunged back into the atmosphere in July and burned up.
Undaunted by the initial American success, the Soviets persisted. After two more disheartening failures, the Soviets launched Salyut 3 in June 1974. A crew visited it for 16 days, but due to docking problems with a later Soyuz, the station was not visited by any more cosmonauts. The Soviets hit their stride beginning in 1974 with a number of increasingly ambitious Salyut missions. The later Salyut stations had more solar power for further experiments and longer missions. In addition, the Soviets perfected the resupply of Salyut by unmanned, automatic vehicles. These robot ships brought fresh supplies of air, food, water, and other consumables, as well as scientific equipment. The Salyuts also had re-startable engines to push them into higher orbits when necessary. These improvements allowed the cosmonauts to establish a string of duration records. One crew stayed in the station for 237 days in 1984.
A new space station, Mir, was launched in February 1986. It had more docking ports and improved crew accommodations: separate compartments with table, chair, and intercom. The same year, the Soviets carried out the first successful transfer of cosmonauts between stations, from its Salyut 7 to the Mir space station. In three years, the Mir cosmonauts completed nine EVAs or "space walks" and carried out a host of scientific experiments. Future modules that can be added to Mir are anticipated, but the breakup of the Soviet Union has put a halt to manned Russian space flights for the immediate future.
Mir lasted well beyond its design lifetime, with crews still inhabiting it in 1998. American astronauts joined the Russians through a series of Mir-Space Shuttle dockings. This entire period was puncuated with moments of nervousness, as the old space station began showing signs of its age. Equipment failers, power losses, and computer crashes began to plague the station, and in June 1998 the United States retrieved its last astronaut from Mir.
The latest, most ambitious space station yet conceived was still on the drawing board as Mir neared the end of its service life. The International Space Station, scheduled for initial in-orbit construction in late 1998, with completion in 2004.
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