COSMOS 1644 DEB
| Launched | 2 April 1985 |
| Flight ended | 14 October 1985 |
| Status | Decayed |
| Launch site | Tyuratam Missile and Space Center, Kazakhstan (Also known as Baikonur Cosmodrome) |
| Owner | Commonwealth of Independent States (former USSR) |
| NORAD ID | 15648 |
| COSPAR ID | 1985-027G |
| Observing |