Uhuru (satellite)

Uhuru

Uhuru (X-ray Explorer Satellite)
Mission type	Astronomy
Operator	NASA
COSPAR ID	1970-107A
SATCAT no.	4797
Website	heasarc.gsfc.nasa.gov/docs/uhuru/uhuru.html
Mission duration	3 years
Spacecraft properties
Dry mass	141.5 kilograms (312 lb)
Start of mission
Launch date	12 December 1970, 10:53:50 (1970-12-12UTC10:53:50Z) UTC
Rocket	Scout B S175C
Launch site	San Marco
End of mission
Last contact	March 1973 (1973-04)
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[1]
Instruments
All-Sky X-Ray Survey
Explorers ← Explorer 41 Explorer 43 →

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.