The Apollo-Soyuz Test Project

This week marks the forty-fifth anniversary of the Apollo-Soyuz Test Project, was the first international space mission, between America and Russia, in which an American Apollo capsule docked with a Russian Soyuz, in a symbolic act of détente between the two superpowers.

The Soyuz vehicle was designated by the Russians as Soyuz-19, but the Apollo spacecraft, originally built for one of the cancelled Moon missions, and the last Apollo to fly, did not receive a numerical designation.

Two astronauts from America and two from Russia performed scientific experiments and observations whilst in orbit. The Commander of the Apollo was Thomas P. Stafford, with Vance D. Brand as Command Module pilot and Donald K. “Deke” Slayton as Docking Module Pilot.

Handshake in Space

Their Russian counterparts were Alexei Leonov (the first person to walk in space in 1965) as Commander and Valeri Kubasov as Flight Engineer.

This project was the last crewed flight launched by NASA until April 1981, when the first Space Shuttle was launched, and the last American flight of a crew-carrying capsule until the Crew Dragon Demo-2 in May of this year.

American and Russian spacecraft differed profoundly in design philosophy, with the Apollo being designed to be flown by the astronauts, whilst the Soyuz relied to a far greater degree upon automation. Russian designers condemned Apollo as being “extremely complex and dangerous”. However, NASA engineers were equally critical of Soyuz, with Christopher C. Kraft, the Director of the Johnson Space Center, stating that “We in NASA rely on redundant components — if an instrument fails during flight, our crews switch to another in an attempt to continue the mission. Each Soyuz component, however, is designed for a specific function; if one fails, the cosmonauts land as soon as possible. The Apollo vehicle also relied on astronaut piloting to a much greater extent than did the Soyuz machine”. However, in talks, differences were resolved, and the Androgynous Peripheral Attach System, or APAS, was agreed upon. One NASA engineer said that he realised that the Russians were prepared to be open with their American colleagues was when they placed on the table the report on the Soyuz-11 mission, in June 1971, in which three cosmonauts died due to depressurisation caused by a faulty valve.

To enable an Apollo to dock with a Soyuz required the use of a special Docking Module, carried below the Apollo capsule on its Saturn Ib launch vehicle, in the same way that the Lunar Module for the moon missions had been. This module, which had to be docked with by the Apollo and extracted from its shroud, served both as an airlock between the 34 kPa pure oxygen atmosphere in the Apollo and the oxygen/nitrogen mix at 100 kPa (sea level pressure), reduced to 70 kPa for docking, aboard the Soyuz, a

nd as an adapter between the two incompatible docking systems.

The two spacecraft were launched on 15th July, and docked on 17th July. Three hours after docking, the two commanders shook hands. The crews later visited each other’s spacecraft, and ate together. After remaining docked for 44 hours, the two ships separated, and Apollo remained in orbit for five days, with Soyuz returning to Earth after two days.

It is easy to deride the Apollo-Soyuz Test Project as a mere political stunt, but the precedent of co-operation led to later undertakings such as the Shuttle–Mir program, in which the Space Shuttle docked with a Russian space station, and the use of Soyuz as a ferry, the only one from the retirement of the Shuttle until the recent advent of the Crew Dragon, to the International Space Station; a derivative of the docking gear which attached the Docking Module to the Soyuz remains in use today. The project established the principle of space collaboration, bestowing a legacy of shared endeavour upon present and future spacefarers.

Portrait of ASTP crews


By Griffith Ingram 




Picture Credits: NASA (Painting of docked spacecraft by Robert McCall)

Be sociable; support the BIS!