Mission type | Astronomy |
---|---|
Operator | NASA |
COSPAR ID | 1979-082A |
SATCAT no. | 11532 |
Spacecraft properties | |
Manufacturer | TRW |
Dry mass | 2,660.2 kilograms (5,865 lb) |
Start of mission | |
Launch date | 20 September 1979, 05:27:00 | UTC
Rocket | Atlas SLV-3D Centaur-D1AR |
Launch site | Cape Canaveral LC-36B |
End of mission | |
Decay date | 7 December 1981 |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth |
Eccentricity | 0.00134 |
Perigee altitude | 486.4 kilometres (302.2 mi) |
Apogee altitude | 504.9 kilometres (313.7 mi) |
Inclination | 43.6° |
Period | 94.50 minutes |
The last of NASA's three High Energy Astronomy Observatories, HEAO 3 was launched 20 September 1979 on an Atlas-Centaur launch vehicle, into a nearly circular, 43.6 degree inclination low Earth orbit with an initial perigeum of 486.4 km. The normal operating mode was a continuous celestial scan, spinning approximately once every 20 min about the spacecraft z-axis, which was nominally pointed at the Sun. Total mass of the observatory at launch was 2,660.0 kilograms (5,864.3 lb).[1]
HEAO 3 included three scientific instruments: the first a cryogenic high-resolution germanium gamma-ray spectrometer, and two devoted to cosmic-ray observations. The scientific objectives of the mission's three experiments were: