Kosmos 638

Kosmos 638 (Космос 638) was an uncrewed test of the 1975 Apollo–Soyuz Test Project Soyuz. It carried an APAS-75 androgynous docking system.

This was followed by another uncrewed test of this spacecraft type, Kosmos 672. It was a Soyuz 7K-TM spacecraft.

When the air was released from the orbital module (which is ejected before re-entry of the capsule) it caused unexpected motions with the spacecraft. This led to the next test also being uncrewed.

Mission parameters

 * Spacecraft: Soyuz-7K-TM №71
 * Mass: 6510 to 6680 kg
 * Crew: None
 * Launched: April 3, 1974
 * Landed: April 13, 1974