Orbiting Astronomical Observatory 2
| Technicians in a clean room at NASA’s Kennedy Space Center in Cape Canaveral, Florida, check out the Orbiting Astronomical Observatory 2 before the mission’s Dec. 7, 1968, launch. | |
| Names | OAO-A2, OAO2 | 
|---|---|
| Mission type | Astronomy | 
| Operator | NASA | 
| COSPAR ID | 1968-110A | 
| SATCAT no. | 3597 | 
| Spacecraft properties | |
| Manufacturer | Grumman | 
| Dry mass | 2,012 kilograms (4,436 lb) | 
| Start of mission | |
| Launch date | 7 December 1968, 08:40:09 UTC | 
| Rocket | Atlas SLV-3C Centaur-D | 
| Launch site | Cape Canaveral LC-36B | 
| End of mission | |
| Disposal | Telescope issues | 
| Deactivated | February 1973 | 
| Orbital parameters | |
| Reference system | Geocentric | 
| Regime | Low Earth | 
| Perigee altitude | 768 kilometres (477 mi) | 
| Apogee altitude | 777 kilometres (483 mi) | 
| Inclination | 35.0 degrees | 
| Period | 100.30 minutes | 
| Epoch | 6 January 1969 | 
The Orbiting Astronomical Observatory 2 (OAO-2, nicknamed Stargazer) was the first successful space telescope (first space telescope being OAO-1, which failed to operate once in orbit), launched on December 7, 1968. An Atlas-Centaur rocket launched it into a nearly circular 750-kilometre (470 mi) altitude Earth orbit. Data was collected in ultraviolet on many sources including comets, planets, and galaxies. It had two major instrument sets facing in opposite directions; the Smithsonian Astrophysical Observatory (SAO) and the Wisconsin Experiment Package (WEP). One discovery was large halos of hydrogen gas around comets, and it also observed Nova Serpentis, which was a nova discovered in 1970.