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Soyuz Apollo Test Project

Scarborough, UK
2014 Apr 25
Friday, Day 115

Maintained by:


The Partnership: A History of the Apollo Soyuz Test Project

Press Kit (PDF Download)
The Mission

The Soviet Union readied two spacecraft, two rocket boosters and four crews for the ASTP mission. Three of the crews were at Baikonur for the launch and the other was in Spaceflight Control Centre at Kaliningrad (now renamed Korolyov) near Moscow.

Apollo took into orbit with it the ASTP docking module - a compartment which could be used by both crews in transferring between the oxygen-nitrogen atmosphere in Soyuz 19 and the low pressure oxygen-only atmosphere in Apollo. The Module was carried into orbit sitting below the Apollo in the same way the Apollo LM had been launched for the lunar missions. Using another 'lunar' technique, Apollo turned round after launch, docked with the Docking Module and pulled it away from the rocket.

Painting by Robert McCallThe moment of rendezvous is captured in this NASA painting by Robert McCall

Only one incident marred the mission. During Apollo's return to Earth, the crew missed an item on a checklist because of radio interference on the voice link. It meant that the command module's thrusters were still 'live' while it was descending under the parachute. They fired automatically to try and steady the craft as it swung around. This resulted in poisonous gases entering the spacecraft through atmospheric pressure relief valves. The three crew members suffered blistering to their lungs - they had to use oxygen masks to breathe at one point.

ASTP's was the final splashdown and the last expendable spacecraft to be launched by the US before the Shuttle era began. The next flight into orbit by an American astronaut came in 1981 when Columbia lifted off on its maiden voyage. Soyuz, however, is still flying today - considerably updated from the 1975 model which, in turn, was an evolution from the 1966 version but nevertheless still the same basic structural components.

Soyuz 19 Launch

Soyuz launchThe basic rocket used to launch Soyuz 19 was based on the same vehicle that launched Sputnik and Vostok and still launches Soyuz today. It stands 49.3 metres tall.

The rocket uses three stages - at lift off, a central core fires, together with the four cone-shaped boosters. After two and a half minutes, the boosters are depleted and fall away. Stage two is the central core firing alone. When this too has used all its fuel it falls away allowing the upper stage to fire and place Soyuz into orbit.

Soyuz itself is covered at launch by a protective aerodynamic shroud. On top of the shroud is a small rocket system which may be used to pull the spacecraft away from the rocket in case of an emergency during the ascent. The black objects attached to the shroud are airbrakes which would open out and slow the spacecraft down after an emergency separation.

Apollo Launch

Apollo launchApollo was launched using a Saturn 1B rocket from Launch Complex 39B at the Kennedy Space Center, Florida. The rocket was built in the Vertical Assembly Building (now known as the Vehicle Assembly Building for the Space Shuttle) which was originally constructed for the Apollo Moon landing programme.

In order that the Saturn 1B fit the handling equipment built for the Saturn 5 launcher, a tall pedestal was constructed to place the top of the rocket at the same height as the Saturn 5 - 110 metres. This arrangement was also used to launch Saturn 1B for the Skylab 2, Skylab 3 and Skylab 4 missions.

The only other piloted mission to use the Saturn 1B was Apollo 7 which checked-out the Apollo command and service modules for the first time with a crew aboard. It left from Launch Complex 34 at the Cape Canaveral Air Force Station, which was specially built to handle the rocket. It was the same launch complex where the crew of Apollo 1 died in 1967.

The Soyuz 19 Spacecraft

Soyuz 19 in orbitThis magnificent photograph of Soyuz 19 was taken by the crew of Apollo while the two craft orbited in formation after they had undocked. It was the clearest photograph ever taken of an orbiting Soyuz until that time. The white backdrop is the Earth's cloud cover.

At top is the orbital module, a near-spherical compartment which provides room for the crew to move about, to stow equipment and can act as an airlock. It is covered in a green multi-layered material which provides thermal insulation, keeping the inside at a comfortable temperature. The white discs are radio transmission aerials, and the two silver plates at the very top are the docking system.

Just below, also shrouded in green insulation, is the descent compartment which houses the crew at launch and is the only part of Soyuz to return to Earth.

At bottom, with two panels of solar cells attached, is the instrument unit which houses fuel tanks, batteries and other electrical equipment, and a rocket motor system - the nozzles of which can be seen in the base.

The complete vehicle is 7.5 metres in length and weighs just over 6.5 tonnes.

The Apollo Spacecraft

Apollo in orbitThe crew of Soyuz 19 took this photograph as the two craft flew in formation after separation. In it can be seen the Apollo command module, and behind it the cylindrical service module with its bell-shaped rocket nozzle. The cylinder at the front with the box-like projections is the Docking Module. At the end facing is the three-petal arrangement of the docking unit developed specially for the mission. The idea behind it is that any two craft equipped with such a unit can dock with each other. Both American and Soviet docking units up to that time consisted effectively of a plug (probe) and socket (drogue). Soviet and American designs were not compatible either.

Apollo is 3.9 metres in diameter and the command and service modules together weigh 14.7 tonnes.

The Docking Module is 3.15 metres long and 1.4 metres in diameter. It weighs 2.0 tonnes. The box-shaped object on the side houses gas bottles for storing oxygen and nitrogen to replenish the atmosphere inside the Docking Module.

Date Time (UTC) Event
1975 Jul 15 12:20 Soyuz 19 launched from the Baikonur Cosmodrome by Soyuz 19 rocket into 191 x 218 kilometre orbit at 51.6 degrees inclination with Alexei Leonov and Valeri Kubasov aboard (for the first time ever, two unrelated space missions are being controlled simultaneously as cosmonauts Klimuk and Sevastyanov work aboard Salyut 4)
1975 Jul 15 Atmospheric pressure inside Soyuz 19 is now 10.4 psi/540 mm, rather than the 'normal' 14.7 psi/760 mm
1975 Jul 15 19:50 Apollo (ASTP) launched from the Kennedy Space Center by Saturn 1B rocket (SA-210) into 153 x 166 kilometre orbit with Thomas Stafford, Vance Brand and Donald Slayton aboard
1975 Jul 15 21:04 Apollo separates from the upper stage of the Saturn 1B and starts the manoeuvre aimed at docking with the ASTP Docking Module - it then pulls the module away from the rocket and Apollo is ready for the docking with Soyuz 19
1975 Jul 15 23:10 Apollo crew reports the presence of a mosquito in the cabin - it subsequently disappears and is assumed to have died
1975 Jul 17 08:05 Direct radio contact established between Apollo and Soyuz 19
1975 Jul 17 16:09 Soyuz 19 and Apollo dock together after Soyuz 19 acts as a 'passive' target for Apollo
1975 Jul 17 16:12 Hard-dock and latching between the two spacecraft is achieved - orbit is 217 x 231 kilometres
1975 Jul 17 Soyuz 19 internal pressure is reduced to 9.7 psi/500 mm
1975 Jul 17 16:26 Astronauts Stafford and Slayton enter the Docking Module, close the hatches between the Module and Apollo, and raise the atmospheric pressure from 5.0 psi/255 mm to 9.5 psi/490 mm by introducing nitrogen
1975 Jul 17 18:00 Crews of Salyut 4 and Soyuz 19 exchange greetings as they pass within radio range of each other
1975 Jul 17 19:10 Soyuz 19 crew opens the hatch at the forward end of the orbital module
1975 Jul 17 19:17 After pressures have been equalised at 9.9 psi/510 mm, astronaut Stafford opens the hatch at the Soyuz 19 end of the Docking Module - the way into Soyuz 19 orbital module is now clear
1975 Jul 17 19:19 Astronaut Stafford and cosmonaut Leonov shake hands inside the Docking Module
1975 Jul 17 22:47 The crews part and then close the hatches between the Docking Module and Soyuz 19, pressure in the Docking Module is reduced to 5.0 psi/260 mm and then Stafford and Slayton return to Apollo command module
1975 Jul 18 09:15 Stafford and Brand enter the Docking Module, close the hatches between the Module and Apollo, and raise the atmospheric pressure
1975 Jul 18 10:00 The hatches into Soyuz 19 are opened after pressures are equalised - Leonov enters the Docking Module and Brand transfers into Soyuz 19 to join Kubasov
1975 Jul 18 11:00 The hatches to Apollo are opened after the pressure in the Docking Module has been reduced - Leonov and Stafford join Slayton in Apollo
1975 Jul 18 15:45 Stafford and Leonov enter the Docking Module, close the hatches between the Module and Apollo, and raise the atmospheric pressure
1975 Jul 18 16:01 The hatches into Soyuz 19 are opened after pressures are equalised, Brand and Kubasov then change places with Leonov and Stafford
1975 Jul 18 16:30 The hatches to Soyuz 19 are closed and the pressure in the Docking Module is then reduced to allow the hatches into Apollo to be opened - Brand and Kubasov join Slayton in Apollo
1975 Jul 18 17:30 Both crews take part in an international press conference
1975 Jul 18 19:50 Slayton and Kubasov enter the Docking Module, close the hatches between the Module and Apollo, and raise the atmospheric pressure
1975 Jul 18 20:20 The hatches into Soyuz 19 are opened after pressures are equalised, then Slayton and Kubasov Join Leonov and Stafford in Soyuz
1975 Jul 18 20:49 Stafford and Leonov shake hands
1975 Jul 18 21:00 The hatches to Soyuz 19 are closed after Stafford and Slayton enter the Docking Module - joint activities between the two crews are finished - they then reduce the pressure in the Docking Module
1975 Jul 18 21:35 Stafford and Slayton enter Apollo and close the remaining hatches
1975 Jul 19 12:12 Soyuz 19 and Apollo undock and move away from each other - Apollo is between Soyuz 19 and the Sun, creating a solar eclipse for observation by the Soyuz 19 crew
1975 Jul 19 12:33 Soyuz 19 and Apollo dock together in orbit for a second time - this time Apollo is the passive target
1975 Jul 19 12:40 Hard-dock and latching between the two spacecraft is achieved, but Apollo has to give unplanned assistance by firing its thrusters at the last moment
1975 Jul 19 15:26 Soyuz 19 and Apollo undock again
1975 Jul 19 18:42 Apollo fires its Reaction Control System thrusters and moves away
1975 Jul 19 Atmospheric pressure inside Soyuz 19 is back to the 'normal' 14.7 psi/760 mm
1975 Jul 21 10:10 Soyuz 19 fires its manoeuvring engine to initiate re-entry
1975 Jul 21 10:51 Soyuz 19 lands - 90 kilometres north east of Arkalyk
1975 Jul 24 Crew of Apollo stows unwanted materials in the Docking Module
1975 Jul 24 19:41 Apollo releases the Docking Module
1975 Jul 24 20:37 Apollo fires its Service Propulsion System to initiate re-entry
1975 Jul 24 21:18 Apollo splashes down - 430 kilometres west of Hawaii, it is hoisted aboard the aircraft carrier USS New Orleans with the crew inside
1975 Aug 2 Apollo-Soyuz Docking Module enters the Earth atmosphere as a result of natural decay of the orbit through air drag and is destroyed by frictional heating
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