|Mission type||Test flight for ASTP mission|
|Operator||Soviet space program|
|Mission duration||5 days 22 hours 23 minutes 35 seconds|
|Spacecraft||Soyuz 7K-TM No.4|
|Spacecraft type||Soyuz 7K-TM|
|Launch mass||6680 kg |
|Landing mass||1200 kg|
|Callsign||Буран (Buran - "Blizzard")|
|Start of mission|
|Launch date||2 December 1974, 09:40:00 UTC|
|Launch site||Baikonur, Site 1/5|
|End of mission|
|Landing date||8 December 1974, 08:03:35 UTC|
|Landing site||30 km of the northeast of Arkalyk, Kazakhstan|
|Reference system||Geocentric orbit|
|Regime||Low Earth orbit|
|Perigee altitude||177.0 km|
|Apogee altitude||223.0 km|
Salyut program insignia
Soyuz 16 (Russian: Союз 16, Union 16) was a 1974 crewed test flight for a joint Soviet-US space flight which culminated in the Apollo-Soyuz mission in July 1975. The two-man Soviet crew tested a docking ring and other systems to be used in the joint flight.
|Commander|| Anatoly Filipchenko|
Second and last spaceflight
|Flight Engineer|| Nikolai Rukavishnikov|
|Flight Engineer||Boris Andreyev|
|Flight Engineer||Aleksandr Ivanchenkov|
The Soyuz 16 mission was the final rehearsal and first crewed mission in a program which culminated in the Apollo-Soyuz (ASTP) mission seven months later. The Soviet Union and the United States, Cold War rivals, had signed several arms control treaties in the 1960s and 1970s, and had entered into a period of detente by the early 1970s. In 1972, a treaty was signed to participate in a joint crewed space flight as a symbol of this detente.
Early concepts for a joint flight included docking a Soyuz craft to the American Skylab space station, or an Apollo vehicle docking with a Salyut space station. Once the Americans abandoned their Skylab station in 1974, the Apollo-Salyut concept seemed to be the logical choice, but since the Soviets had started to develop a universal docking adapter for the mission and feared having to publicly reveal details of their military-focused Salyut missions, the two powers opted to link a Soyuz spacecraft with an Apollo spacecraft.
Three test flights of an uncrewed version of the ASTP spacecraft were flown: Kosmos 638, launched 3 April 1974; Kosmos 652, launched 15 May 1974; and Kosmos 672, launched 12 August 1974. These three flights, and Soyuz 16, were all launched with an improved version of a Soyuz booster.
In an unprecedented move, Soviet planners offered to inform their NASA counterparts of the time of the launch, as long as they did not reveal that time to the press. NASA officials refused to agree to that condition and, accordingly, were informed of the launch an hour after it occurred, on 2 December 1974.
During the flight, Cosmonauts Anatoly Filipchenko and Nikolai Rukavishnikov tested the androgynous docking system to be used for the ASTP mission by retracting and extending a simulated 20 kg American docking ring. The crew also tested modified environmental systems, new solar panels and improved control systems, as well as a new radar docking system. air pressure was reduced from 760 mm to 540 mm and oxygen raised from 20% to 40% to test reducing the planned transfer time to Apollo from two to one hour. On 7 December 1974, the docking ring was jettisoned with explosive bolts to test emergency measures if the capture latches got stuck during the ASTP flight.