_drawing.png) Soyuz 7K-TM | |
| Mission type | Orbital test flight |
|---|---|
| Operator | Soviet space program |
| COSPAR ID | 1974-018A |
| SATCAT no. | 7234 |
| Mission duration | 9 days, 21 hours and 35 minutes |
| Spacecraft properties | |
| Spacecraft | Soyuz 7K-TM s/n 71 |
| Manufacturer | NPO Energia |
| Launch mass | 6,570 kg (14,480 lb) |
| Start of mission | |
| Launch date | 3 April 1974, 07:30 GMT[1] |
| Rocket | Soyuz-U |
| Launch site | Baikonur 31/6 |
| End of mission | |
| Disposal | Deorbited |
| Landing date | 13 April 1974, 05:05 GMT[1] |
| Orbital parameters | |
| Reference system | Geocentric |
| Perigee altitude | 187 km (116 mi) |
| Apogee altitude | 309 km (192 mi) |
| Inclination | 51.8° |
| Period | 89.4 min |
Kosmos 638 (Russian: 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.[2] It was a Soyuz 7K-TM spacecraft.[2]
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.[2] This led to the next test also being uncrewed.[2]