RADCAL
Radar calibration satellite
From Wikipedia, the free encyclopedia
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 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] |
Design
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]
Mission
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]