Kosmos 638

Kosmos 638 (Russian: Космос 638, meaning Cosmos 638) was an unmanned test of the ASTP Soyuz. It carried an APAS-75 androgynous docking system.

This was followed by another unmanned 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 unmanned.