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On 17 July 1975, Thomas Stafford of the United States shook hands with Alexei Leonov of the Soviet Union in the docking ring of joined Apollo and Soyuz spacecraft. Thus ended five years of work and planning for the first joint space mission by the United States and the Soviet Union. Up until 1969, the U.S. and Soviet Union had been engaged in a race in space. The Soviet Union took an early lead, putting up the first man in space and the first spacewalker, but the ultimate prize, the Moon landing, went to the United States.

While the space race took place, there were also cooperative space efforts, primarily the sharing of scientific data, and overtures between the U.S. and Soviet Union. President John F. Kennedy had suggested joint space missions as early as 1963, and in 1967 and 1968 a pair of space treaties were signed by the two countries that would allow for joint rescue of astronauts/cosmonauts and the return of space objects to their country of origin. In fact, during the Apollo 13 mission in April 1970, the Soviet Union offered assistance under the rescue treaty. Later that year, NASA Administrator Thomas O. Paine exchanged a series of letters with the President of the Soviet Academy of Sciences, Mstislav V. Keldysh, which led to a series of informal discussions on the possibility of U.S.-USSR joint rescue capability. In early 1971, the U.S. proposed a joint mission to test the docking hardware that was being designed, and the Soviets responded positively.

Talks in the United States and Soviet Union continued over the next two years, led by George Low of the U.S. and Boris Petrov of the USSR, and the goal of docking an American Apollo spacecraft with a Soviet Soyuz spacecraft in 1975 was formalized in the "Agreement Concerning Cooperation in the Exploration and Use of Outer Space for Peaceful Purposes," which was signed during the 1972 Strategic Arms Limitation Treaty talks between the United States and the Soviet Union. A number of problems remained, such as the actual design of the docking module and the different atmospheres in the two spacecraft. The Soyuz spacecraft was designed with nitrogen/oxygen mixed atmosphere that was pressurized at 14 psi, and Apollo spacecraft was designed with a pure oxygen atmosphere pressurized at 5 psi; the different compositions and pressures could have caused problems in both spacecraft. However, these problems were resolved during the remaining time before the mission with a minimum of acrimony. The work on the Apollo-Soyuz Test Project (ASTP) also served to break down barriers between the two nations as the Soviet Union opened its spacecraft and training facilities to American visitors, including journalists, for the first time. The astronauts, Thomas Stafford, Donald "Deke" Slayton, and Vance Brand, along with cosmonauts Alexei Leonov and Valeriy Kubasov, began language and mission training in 1973, after the respective crews were announced by the American, Glynn Lunney, and Soviet, Konstantin Bushuyev, project directors. The training took place at space centers in the United States and Soviet Union.

The mission itself began with the Soyuz launch from Baykonur Cosmodrome on 15 July 1975, followed by the Apollo launch from Kennedy Space Center 7 hours later. The docking in space of the two spacecraft took place at 2:17 p.m. U.S. Central Daylight Time on 17 July. Two days of joint operations followed. After separation, the Soyuz remained in space for almost two days before landing in the USSR on 21 July. The Apollo spacecraft remained in space for another three days before splashing down near Hawaii on 24 July. The mission was a resounding success for both Americans and Soviets. They achieved their goal of obtaining flight experience for rendezvous and docking of human spacecraft. In addition, they also demonstrated in-flight intervehicular crew transfer, as well as accomplished a series of scientific experiments.

Despite the promise of international cooperation created by the landmark mission, ASTP proved to be more of an end than a beginning. The next time U.S. astronauts and Russian cosmonauts would fly together would not be until 1994, three years after the fall of the Soviet Union, and the next time a U.S. and Russian spacecraft would dock together would be in June 1995.

Author: Liz Suckow
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