Uhuru (satellite)
Uhuru (X-ray Explorer Satellite) | |
| Mission type | Astronomy |
|---|---|
| Operator | NASA |
| COSPAR ID | 1970-107A |
| SATCAT no. | 4797 |
| Website | heasarc |
| Mission duration | 3 years |
| Spacecraft properties | |
| Dry mass | 141.5 kilograms (312 lb) |
| Start of mission | |
| Launch date | 12 December 1970, 10:53:50 UTC |
| Rocket | Scout B S175C |
| Launch site | San Marco |
| End of mission | |
| Last contact | March 1973 |
| Decay date | 5 April 1979 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.002956 |
| Perigee altitude | 520.0 kilometers (323.1 mi) |
| Apogee altitude | 560.0 kilometers (348.0 mi) |
| Inclination | 3.0 degrees |
| Period | 95.70 minutes |
| Epoch | 12 December 1970, 05:54:00 UTC |
| Instruments | |
| All-Sky X-Ray Survey | |
Uhuru was the first satellite launched specifically for the purpose of X-ray astronomy. It was also known as the X-ray Explorer Satellite, SAS-A (for Small Astronomy Satellite A, the first of the three-spacecraft SAS series), SAS 1, or Explorer 42. The NASA observatory was launched on 12 December 1970 into an initial orbit of about 560 km apogee, 520 km perigee, 3 degrees inclination, with a period of 96 minutes. The mission ended in March 1973. Uhuru was a scanning mission, with a spin period of ~12 minutes. It performed the first comprehensive survey of the entire sky for X-ray sources, with a sensitivity of about 0.001 times the intensity of the Crab nebula.