SURCAL
The Surveillance Calibration satellites were a series of radar calibration satellites for the Naval Space Surveillance radar system. They were launched in the 1960s.
Background
The SURCAL series of satellites were produced by the Naval Research Laboratory to act as test and calibration targets for the Naval Space Surveillance radar. The first SURCAL satellite was intended to remain attached to the launch vehicle and was a 5.5 inch long, 5.5 inch diameter cylinder. The other four SURCAL satellites were box-shaped with solar panels, a transponder, and antennas. They transmitted a 216 MHz signal on command.Launches
| Name | COSPAR | Launch date | Rocket | Mass | Re-entry |
| SURCAL 1 | N/A | 24 January 1962 | Thor-Able-Star | 98.5 kg | Launch failure |
| SURCAL 2 | 1962 B Tau 4 | 13 December 1962 | Thor-Agena-D | 37 kg | 18 Jan 1966 |
| SURCAL 3 | 1962-021F | 15 June 1963 | Thor-Agena-D | 3 kg | 5 Jul 1963 |
| SURCAL 4 | 1965-016G | 9 March 1965 | Thor-Agena-D | 5 kg | 27 March 1981 |
| SURCAL 5 | 1965-065K | 9 March 1965 | Thor-Able-Star | In orbit |