Today, July 17, 2020, marks 45 years since ending of the Space Race with the flight of the Apollo-Soyuz Test Project (ASTP) and handshake in space between the two commanders. The launch of the Apollo flight was the 31st manned American space mission while the Soyuz flight was the 26th manned Soviet space mission. They were the 57th and 58th manned flights overall.
The Apollo and Soyuz capsules docking above Earth depicted by artist Robert McCall (NASA)
The first step that would lead to Apollo-Soyuz was the Dryden-Blagonravov agreement. After John Glenn's orbital flight in 1962, President John F. Kennedy and Soviet Premier Nikita Khrushchev exchanged letters that led to discussions between NASA Deputy Administrator Hugh Dryden and Soviet scientist Anatoly Blagonarov. Their subsequent agreement called for cooperation on the exchange of data from weather satellites and a study of the Earth's magnetic field, as well as the joint tracking of NASA's Echo II balloon satellite. Over time, though, tensions would increase and both sides would very rarely acknowledge the achievements of the other: The Soviet Union was especially critical of the American Apollo missions, often alluding to the US's presence in east Asia and engagement in the Vietnam War.
The Apollo flight was commanded by Tom Stafford, a veteran of three previous space missions- Gemini 6, Gemini 9A, and Apollo 10. Its command module pilot was Vance Brand, a rookie who would later command three Space Shuttle missions. The docking module pilot, a role exclusive to this mission, was Mercury astronaut Deke Slayton. Despite being selected as part of NASA's first class of astronauts in 1959, this was his only flight; he was grounded due to a heart condition shortly before his planned flight in 1962 and remained grounded until 1972. At the time, he was the oldest person to fly in space (that record would eventually be broken by one of his own classmates, John Glenn). The mission's backup commander was Alan Bean, former moonwalker and Skylab mission commander. Its backup command module pilot was Ron Evans, the command module pilot of Apollo 17. The backup docking module pilot was Jack Lousma, another Skylab astronaut who would later command the Space Shuttle. The Soyuz flight was commanded by Alexei Leonov, the first person to perform a spacewalk. Its flight engineer was Valery Kubasov. Both Leonov and Kubasov were part of the original crew of the ill-fated Soyuz 11 mission. The backup commander and flight engineer were Anatoly Filipchenko and Nikolai Rukavishnikov.
Top L-R: Stafford, Leonov; bottom L-R: Slayton, Brand, Kubasov (NASA)
The ASTP involved the docking of an American Apollo command and service module (CSM) with a Soviet Soyuz 7K-TM spacecraft. The Soyuz was part of the ongoing Soyuz program, which still to this day carries crew to the International Space Station, and was given the designation Soyuz 19. Its callsign for this mission was simply "Soyuz", meaning "union". In contrast, the Apollo mission was not part of the Apollo program. The actual Apollo 18 mission was a cancelled lunar flight. Although the press has referred to the ASTP's Apollo as "Apollo 18", this is incorrect. Its callsign was "Apollo".
The Apollo spacecraft was launched with a specially designed docking module. It acted as both an airlock — since the two spacecraft had different pressurizations — and an adapter. The surplus Apollo hardware left over from cancelled missions did not have the unique docking collar jointly developed by NASA and the Academy of Sciences of the Soviet Union. One end of the docking module was attached to the Apollo using the same mechanism used on the Lunar Module and Skylab, known as the "probe-and-drogue". The other end had the docking collar, which Soyuz 19 carried. The collar was also reusable, allowing the two spacecraft to separate in case of a malfunction. The CSM and Saturn IB launch vehicle were both surplus and the docking module had to be retrieved from the S-IVB upper-stage of the Saturn while in orbit, as was done with the Lunar Module during the Apollo program.
Soyuz 19 launched on July 15, 1975, at 8:20 a.m. EDT from the Baikonur Cosmodrome in Kazakhstan. The Apollo launched on the same day at 3:50 p.m. EDT from Launch Complex 39B at the Kennedy Space Center in Florida. Hard-dock occurred on July 17 at 12:12 p.m. and the hatches between the vehicles were opened at 3:17 p.m. The first international handshake in space happened over the French city of Metz. The crews were read a statement from Soviet Premier Leonid Brezhnev and received a phone call from US President Gerald Ford. A meal was shared and commemorative gifts were exchanged before the hatch was closed for the day.
Brand and Kubasov worked in the Soyuz the next day while Leonov joined Stafford and Slayton in the Apollo. Tours of each vehicle were broadcasted to Earth. The joint crews conducted science experiments, exchanged flags and gifts, signed certificates, ate together, and conversed in each other's languages. One of these commemorative gifts were tree seeds that were later planted in the two countries. A particular scientific experiment involved the effects of weightlessness on fish eggs at various stages of development.
Leonov and Stafford's historic handshake in space (image source: cnn.com )
On July 19 at 8:02 a.m., after 44 hours together, the two ships separated. The Apollo created an artificial solar eclipse to allow the cosmonauts in the Soyuz to take photographs of the sun's corona. The two spacecraft docked one more time briefly and finally went their separate ways at 11:26. This would be the last international docking until the Shuttle-Mir program in the 1990s.
Soyuz 19 stayed in orbit an extra day to carry out life-science experiments and returned to Earth on July 21 at 6:51 a.m. It was the first Soviet mission with a televised launch and landing. Apollo splashed down in the Pacific Ocean at 5:18 p.m. on July 24. In fact, this was the only point in the mission in which a serious problem occurred. The crew was accidentally exposed to toxic hydrazine and nitrogen tetroxide gases, which was caused by unignited reaction control system (RCS) hypergolic propellants entering the cabin. The RCS was left on during descent and the toxic fumes were sucked inside as the capsule drew in outside air. Brand lost consciousness briefly and all three astronauts were hospitalized for two weeks in Honolulu, Hawaii. Afterwards, Brand took responsibility for the incident, claiming he was unable to hear Stafford call off one item of the reentry checklist (the closure of two switches that would have automatically shut off the RCS) due to high noise levels in the cabin at the time.
Apollo-Soyuz was the final flight of an Apollo spacecraft and the last manned American capsule flight until the launch of SpaceX Demonstration Mission-2 45 years later in May 2020. Immediately after launch, LC-39B began to be converted to support Space Shuttle launches, the first of which would be Challenger STS-51-L. This particular Apollo flight was also the last manned capsule to splash down in the ocean. The next time this will happen is when Demonstration Mission-2 returns from the International Space Station.
ASTP cartoon drawn by Leonov (NASA)
The technical, political, and cultural legacies of the Apollo-Soyuz Test Project are still prominent today. The docking collar used during this mission served as the basis for future international docking hardware, particularly those mechanisms used on the Mir space station and ISS. This historic event brought the end of the 18-year long Space Race and wound up making the exploration of space both more international and more competitive, despite the press's tendency to downplay the other's technical capabilities. It would lead to the Shuttle-Mir Program of the 1990s and the International Space Station.
The Apollo command module is on display at the California Science Center in Los Angeles, California. The descent module of Soyuz 19, the only part of the Soyuz spacecraft that remained intact after reentry, is on display at the RKK Energiya museum in Korolyov, Moscow Oblast, Russia. The National Air and Space Museum in Washington, D.C. features a display of the Apollo and Soyuz docked together using the restored Apollo CSM used for testing prior to the mission, a model of the Soyuz, and the back-up docking module. Another full-sized mockup of the docked spacecraft is located at the Cosmosphere in Hutchinson, Kansas.
Quick Facts - Apollo
Commander: Thomas P. Stafford
Command Module Pilot: Vance D. Brand
Docking Module Pilot: Donald K. "Deke" Slayton
Backup Commander: Alan L. Bean
Backup Command Module Pilot: Ronald E. Evans
Backup Docking Module Pilot: Jack R. Lousma
Launch Vehicle: Apollo Saturn IB
Launch Date: 07/15/1975
Launch Site: LC-39B, Kennedy Space Center
Landing Date: 07/24/1975
Recovery Carrier: USS New Orleans
Quick Facts - Soyuz
Commander: Alexei A. Leonov
Flight Engineer: Valery N. Kubasov
Backup Commander: Anatoly Filipchenko
Backup Flight Engineer: Nikolai Rukavishnikov
Launch Vehicle: Soyuz-U
Launch Date: 07/15/1975
Launch Site: Baikonur Cosmodrome, Kazakhstan
Landing Date: 07/21/1975
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Crowell, Rachel. “Benchmarks: July 15-24, 1975: Apollo-Soyuz Mission Launches Space Collaboration.” EARTH Magazine, 26 June 2017, www.earthmagazine.org/article/benchmarks-july-15-24-1975-apollo-soyuz-mission-launches-space-collaboration.
Dunbar, Brian. “The Apollo-Soyuz Mission.” NASA, NASA, 16 Apr. 2015, www.nasa.gov/mission_pages/apollo-soyuz/astp_mission.html.
Redmond, Charles. “History - The Flight of Apollo-Soyuz.” NASA, NASA, 22 Oct. 2004, history.nasa.gov/apollo/apsoyhist.html.