Apollo-Soyuz Test Project (ASTP) was the first international space project
involving piloted spaceflight. After three long years of preparations, a
U.S. Apollo spacecraft and a Soviet Soyuz capsule linked up in Earth orbit
in July 1975. It was an important milestone in the history of space
exploration since it proved for the first time that political adversaries
could work together to implement a complex space project.
The Apollo Soyuz Test Project
Saturn 1B launch vehicle thunders away from KSC's Launch Complex 39B at
3:50 p.m. on July 15, 1975.
Aboard the Apollo Command Module are ASTP astronauts Thomas Stafford,
Vance Brand and Donald Slayton.
The astronauts would rendezvous and dock with a Soyuz spacecraft, launched
that morning from the Baikonur launch facility in the Soviet Union, with
arriving Soviet cosmonauts Aleksey Leonov and Valerly Kubasov.
its origins in October 1970 when representatives from the National
Aeronautics and Space Administration (NASA) and the USSR Academy of
Sciences met in Moscow to discuss the possibility of a joint piloted space
sides had compelling reasons to participate in such a venture. For the
United States, the Apollo Moon program was to end by 1972. Flights to the
Skylab space station would follow in 1973 and 1974, but after that there
would be a hiatus of nearly five years before the introduction of a
new-generation space transportation system (which later became the Space
Shuttle). A joint flight in the period between would provide NASA with
valuable spaceflight experience. For the Soviets, a joint mission would be
a useful public relations exercise by demonstrating that their space
technology was on par with that of the United States. After losing the
race to the Moon, such a joint flight would present a competitive Soviet
space program-a view that had been difficult to support given its recent
track record of unremarkable space missions.
President Richard M. Nixon and Soviet Council of Ministers Chairman Alexey
N. Kosygin signed a formal document on May 24, 1972 that called for the
docking of an Apollo to a Soyuz in Earth orbit in July 1975. The Americans
called the project the Apollo-Soyuz Test Project (ASTP) while the Russians
referred to it as the Apollo-Soyuz Experimental Flight (or “EPAS” in its
Russian abbreviation). Planning for the mission began in July 1972 with
the arrival of Soviet scientists at NASA's Lyndon B. Johnson Space Centre
near Houston, Texas.
Apollo Commander, Astronaut Thomas
P. Stafford (in foreground) and Soyuz Commander,
Cosmonaut Alexei A. Leonov make their historic handshake in space during
Russian/American docking mission known as the ASTP, or Apollo Soyuz Test
The handshake took place after the hatch to the Universal Docking Adapter
(UDA) was opened.
Stafford is inside the UDA and Leonov is inside the Soyuz.
for the project were announced by the spring of 1973. Space veteran Thomas
P. Stafford, would command the flight accompanied by two rookies, Vance D.
Brand and Donald K. “Deke” Slayton. Slayton was one of the “original
seven” Mercury astronauts selected in 1959 but had been grounded for a
decade due to a minor heart problem. On the Soviet side, commander Alexei
A. Leonov, the colourful cosmonaut who had made the first ever spacewalk in
1965, was joined by flight engineer Valeri N. Kubasov, a veteran of a 1969
Soyuz flight. Both Leonov and Kubasov had narrowly escaped death in 1971
when they had been slated to fly a mission to the Soviet Salyut space
station. Just before launch, they had been replaced by a reserve crew, who
subsequently were killed in space due to a valve failure.
the Apollo and Soyuz were vastly different spacecraft with incompatible
docking systems, American and Soviet planners decided designed and built
an interface known as the Docking Module. The 3-meter-long, 1.5-meter-wide
cylinder not only served as a docking interface but also as an airlock
module between the different atmospheres of the two spacecraft. The
Docking Module, carried into orbit with Apollo, used a docking system that
would lay the foundation for a standard international docking system.
Apollo spacecraft was similar to the types used on the Moon missions,
consisting of a conical Command Module attached to a cylindrical Service
Module. The Soyuz was modified from the 7K-T version used as a ferry to
the Salyut space stations. The ASTP Soyuz was known as the 7K-M and was
equipped with new solar panels and modified controls. Apollo would be
launched by a Saturn 1B left over from the Apollo Moon project, while the
Soyuz would be launched by a standard three-stage Soyuz booster based on
the old R-7 intercontinental ballistic missile (ICBM).
July 1973 and May 1975, Soviet and American delegations visited each
other's countries several times. During the exchanges, American astronauts
trained at the Russian Star City complex outside of Moscow while the
Soviet crews trained at Johnson Space Centre.
contrast to American openness about their space program, the Soviets were
careful to conceal many important aspects of their space program, mostly
because such a large portion of their space program had ties to the
military. For example, throughout the project, the Soviets never revealed
who actually designed and built the Soyuz spaceship (the company now known
as RKK Energia). Instead, they used the cover of the USSR Academy of
Sciences to give the impression that their space program was run by the
the most difficult obstacles in planning ASTP was the language barrier. In
order to ease communication, the American crewmembers learned Russian
while the Soviets learned English. Planners agreed that the crews would
speak each other's languages as much as possible during rendezvous and
joint mission began exactly on schedule. The Soyuz, known as Soyuz 19, was
successfully launched into from the Soviet launch complex at Baikonur on
July 15, 1975. About seven-and-a-half hours after the Soyuz launch, Apollo
was launched into orbit from the NASA's Kennedy Space Centre in Florida.
Soon after, Stafford's crew manoeuvred the Apollo to link up with the
Docking Module, which was stowed inside an adaptor above the Saturn 1B
series of extensive manoeuvres, both Apollo and Soyuz entered similar
orbits and began tracking each other by about 9 a.m. (all times in Eastern
Time) on July 17. The two spacecraft made physical contact with each other
at 12:09 p.m. the same day; cosmonaut Leonov reported to the ground that
“Soyuz and Apollo are shaking hands now.” Hard docking between the
Apollo/Docking Module and the Soyuz was completed minutes later.
hours after docking, astronauts Stafford and Slayton opened their Apollo
hatch into the Docking Module. Soon after Leonov opened his hatch into the
module and greeted Stafford. Their historic handshake was televised live
to the world. During four hours of joint activities, the crews received
congratulations from Soviet General Secretary Leonid Brezhnev and U.S.
President Gerald Ford. The crews signed international certificates and
exchanged commemorative items such as flags and plaques. After these
activities, the crews returned to their own spacecraft to perform
period of joint activities followed on July 18 when astronaut Brand
entered the Soyuz and Leonov joined Stafford and Slayton in Apollo. The
crews provided televised tours of each other's spacecraft and ate lunch
together. After a third transfer between spacecraft later in the day and a
joint press conference, the crews once again returned to their respective
and Soyuz separated from each other at 8:02 a.m. on July 19. At this
point, the Apollo vehicle blocked the Sun, simulating a solar eclipse; the
cosmonauts were thus able to photograph the solar corona. (The Apollo was
termed an “occulting” object.) The two ships re-docked briefly (with the
Soyuz system in motion rather than the Apollo) and then finally parted
ways permanently after about three hours. During their slow drift away,
the two crews performed an ultraviolet atmospheric absorption experiment.
Approximately 30 hours after undocking, Leonov and Kubasov returned to
Earth, landing in a remote area of Kazakhstan at 6:51 a.m. on July 21. The
landing was televised live to the world.
remained in orbit much longer. During a period of three days, Stafford's
crew performed a large number of scientific experiments focused on
astronomy, biology, materials science, and Earth observation. The Apollo
Command Module splashed down safely at 5:18 p.m. on July 24 about 500
kilometres west of Hawaii in the Pacific Ocean. It was the last water
landing for American astronauts.
critical event during the whole mission occurred during the Apollo re-entry
when noxious nitrogen tetroxide gas from the reaction control thruster
system accidentally entered the internal cabin. The crew was briefly
exposed to toxic components and experienced severe eye irritation and
discomfort in the lungs. There were, however, no long-term effects.
the first joint piloted mission was an outstanding success by all
standards. Mission planners in two adversarial nations were able to
demonstrate that social, cultural, and political obstacles could be
overcome in order to facilitate the peaceful exploration of space. But the
international climate deteriorated in the late 1970s, dashing hopes that
ASTP would lead to more complex joint flights such as between the Space
Shuttle and the Soviet Salyut station. ASTP did, however, leave an
important legacy. It showed that substantive international cooperation was
possible. It is this legacy that the International Space Station carries
forward in the present day.