COSMOS 1839
| Launched | 23 April 1987 |
| Flight ended | 7 May 1991 |
| Status | Decayed |
| Launch site | Tyuratam Missile and Space Center, Kazakhstan (Also known as Baikonur Cosmodrome) |
| Owner | Commonwealth of Independent States (former USSR) |
| NORAD ID | 17903 |
| COSPAR ID | 1987-036B |
| Alternative names |
GLONASS GLONASS 18 |
| Observing |
Launched alongside
COSMOS 1838 COSMOS 1840 SL-12 R/B(1) SL-12 PLAT SL-12 R/B SL-12 R/B(2) SL-12 R/B SL-12 DEB SL-12 DEB SL-12 DEB SL-12 DEB SL-12 DEB