RADCAL
RADCAL
Radar calibration satellite
RADCAL (short for RADar CALibration Satellite) was a radar calibration satellite launched and operated by the United States Air Force. It was active from June 1993 until it stopped communicating in May 2013.
Manufacturer photograph of RADCAL | |
| Mission type | Radar calibration |
|---|---|
| Operator | United States Air Force |
| COSPAR ID | 1993-041A  |
| SATCAT no. | 22698 |
| Mission duration | 3 year (design life)[1] |
| Spacecraft properties | |
| Launch mass | 89.3 kilograms (197 lb)[1] |
| Start of mission | |
| Launch date | 23:30:00 UTC on 25 June 1993 (1993-06-25UTC23:30Z) UTC |
| Rocket | Scout S217C |
| Launch site | Vandenberg SLC-5 |
| End of mission | |
| Declared | 2013 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.00754 |
| Perigee altitude | 791 kilometres (492 mi) |
| Apogee altitude | 9,000 kilometres (5,600 mi) |
| Inclination | 89.5 degrees |
| Period | 101.40 minutes |
| Epoch | 26 June 1993 [2] |
Construction
RADCAL was built by Defense Systems Inc. as United States Air Force Space Test Program payload P92-1.[3] It was built under a one-year contract-to-launch[1] and cost $10 million.[4]
Components
Payload included two C Band transponders (operating at the same frequency as space-detection radars[3]), a Doppler beacon that transmitted at 150 and 400 MHz, and a pair of modified Trimble Inc. TANS Quadrex Global Positioning System receivers.[1] The receivers were used to determine the satellite's orbit as a reference for calibrating space detection radars.[3] It also carried the Small Satellite Power System Regulator, an experiment testing improved battery charging on solar panel-equipped vehicles.[5][4]
Launch
RADCAL launched into polar orbit at 23:30:00 UTC on 25 June 1993[2] from Vandenberg Air Force Base's Space Launch Complex 5. The launch vehicle was Scout S217C.[3]
Operation
RADCAL was used to calibrate ground-based space tracking radars: they would track it and compare their estimated position to its true position.[5] By the end of its operational lifetime, it was one of only two functional radar performance monitoring satellites (along with DMSP F-15) and was actively used by a number of civilian and military organizations.[6] Its GPS receivers were used in experiments to determine its attitude in space.[7] It was the first satellite to use a GPS to determine its attitude.[8] RADCAL was designed to last for three years, but remained operational until May 2013.[9]
- Krebs, Gunter D. "RadCal (P92-1)". Gunter's Space Page. Retrieved 20 October 2021.
- "NASA - NSSDCA - Spacecraft - Telemetry Details". nssdc.gsfc.nasa.gov. Retrieved 20 October 2021.
- McDowell, Jonathan. "Jonathan's Space Report No. 159". Jonathan's Space Report. Retrieved 20 October 2021.
- "New Satellite to Improve Radar Tracking of Spacecraft, Planes, Missiles With PM-Space Shuttle". AP News. 26 June 1993. Retrieved 20 October 2021.
- Kramer, Herbert J. (30 January 2019). Observation of the Earth and Its Environment: Survey of Missions and Sensors. Springer. p. 1102. ISBN 978-3-642-56294-5. Retrieved 21 October 2021.
- Martin, Larry; Fisher, Nicholas; Jones, Windell; Furumo, John; Heong, James Ah Jr.; Umeda, Monica; Shiroma, Wayne (9 August 2011). "Ho'oponopono: A Radar Calibration CubeSat". Small Satellite Conference. Retrieved 21 October 2021.
- Cohen, Clark E.; Lightsey, E. Glenn; Parkinson, Bradford W.; Feess, William A. (1994). "Space flight tests of attitude determination using GPS". International Journal of Satellite Communications. 12 (5): 427–433. doi:10.1002/sat.4600120504. ISSN 1099-1247. Retrieved 2021-10-21.
- Lawrence, Taylor. "Satellite". Kirtland Air Force Base. 377th Air Base Wing Public Affairs. Retrieved 21 October 2021.