Portal:Spaceflight/On This Day/21 January
- 1959 - A Thor-Agena is damaged after the upper stage ignition sequence is accidentally initiated during a ground test, whilst attached to the first stage.
- 1964 - A Delta B launches the Relay 2 communication satellite
- 1965 - An Atlas-D fails to launch two OV1 scientific satellites
- 1970 - A Voskhod rocket launches a Zenit-4 spy satellite
- 1971 - A Voskhod rocket launches a Zenit-2M spy satellite
- 1971 - A Titan 23B launches a KH-8 spy satellite
- 1975 - A Kosmos-2I launches a DS-P1-Yu radar target satellite
- 1981 - A Kosmos-3M launches a DS-P1-M ASAT target satellite
- 1982 - A Titan 24B launches a KH-8 spy satellite
- 1987 - A Kosmos-3M launches a Strela communication satellite
- 1992 - A Soyuz-U launches a Yantar spy satellite
- 2000 - An Atlas IIA launches a DSCS communication satellite
- 2008 - A PSLV launches the Israeli TecSAR spy satellite.