High Energy Astronomy Observatory 1
| Names | HEAO-1, HEAO-A |
|---|---|
| Mission type | orbiter |
| Operator | NASA |
| COSPAR ID | 1977-075A |
| SATCAT no. | 10217 |
| Mission duration | 1 year, 7 months and 2 days |
| Spacecraft properties | |
| Manufacturer | TRW |
| Payload mass | 2,551.9 kg (5,626 lb) |
| Dimensions | height:5.68 m (18.6 ft) radius: 2.67 m (8 ft 9 in) |
| Start of mission | |
| Launch date | 12 August 1977 |
| Rocket | Atlas Centaur |
| Launch site | CCAFS LC-36B |
| End of mission | |
| Deactivated | 9 January 1979 |
| Decay date | 14 March 1979 |
| Orbital parameters | |
| Eccentricity | 0 |
| Perigee altitude | 432 km (268 mi) |
| Apogee altitude | 432 km (268 mi) |
| Inclination | 23° |
| Period | 93.5 min |
| Epoch | 13 August 1977 00:00:00 UTC |
HEAO-1 was an X-ray telescope launched in 1977. HEAO-1 surveyed the sky in the X-ray portion of the electromagnetic spectrum (0.2 keV – 10 MeV), providing nearly constant monitoring of X-ray sources near the ecliptic poles and more detailed studies of a number of objects by observations lasting 3–6 hours. It was the first of NASA's three High Energy Astronomy Observatories, launched on August 12, 1977 aboard an Atlas rocket with a Centaur upper stage, operated until 9 January 1979. During that time, it scanned the X-ray sky almost three times
HEAO included four X-ray and gamma-ray astronomy instruments, known as A1, A2, A3, and A4, respectively (before launch, HEAO 1 was known as HEAO A). The orbital inclination was about 22.7 degrees. HEAO 1 re-entered the Earth's atmosphere on 15 March 1979.