Docking Module, ASTP Backup


Display Status:

This object is on display in the Space Race exhibition at the National Air and Space Museum in Washington, DC.

Collection Item Summary:

In 1971, the US and the USSR agreed to carry out a docking in orbit of the Apollo and Soyuz spacecraft. This project was called the Apollo-Soyuz Test Project (ASTP). An airlock was needed to transition from the American cabin pressure system of 5 pounds per square inch pure oxygen to the Soviet mixed oxygen/nitrogen system at normal atmospheric pressure (about 14.7 psi). NASA contracted with North American Rockwell, the CSM contractor, to build the Docking Module (DM). On the front was mounted the three-leaf androgynous docking system, which was jointly designed by US and Soviet engineers. It could be used in either a passive (retracted) or active (extended) docking configuration. The DM launched with the Apollo on July 15, 1975 and was used in the historic docking with Soyuz 19 two days later. After undocking on July 19, the American crew of Stafford, Brand and Slayton performed scientific experiments in the DM.

The Smithsonian's DM is the backup to the flight DM. It was transferred from NASA to the Smithsonian in 1980.

Collection Item Long Description:

Inventory Number


Credit Line

Transferred from the National Aeronautics and Space Administration

Country of Origin

United States of America


Structure: Aluminum plate


Overall: 9 ft. 1 13/16 in. deep x 10 ft. 4 in. long x 4 ft. 8 in. diameter, 4435.7 lb. (278.92 x 314.96 x 142.24cm, 2012kg)

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


SPACECRAFT-Manned-Test Vehicles

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