Explorer 42

Launch data: Designation 04797 / 70107A Launch date 12 Dec 1970 Launch site San Marco Launch vehicle Scout-B (#71) Mission Scientific: X-ray astronomy Perigee/Apogee 521/570 km Inclination 3° Period 95.5 min Mass 143 kg

Description:

• 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, being first of the three-spacecraft SAS series), SAS 1, or Explorer 42. The 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.

End of life: