Orbiting Astronomical Observatory 2

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.
NamesOAO-A2, OAO2
Mission typeAstronomy
OperatorNASA
COSPAR ID1968-110A
SATCAT no.3597
Spacecraft properties
ManufacturerGrumman
Dry mass2,012 kilograms (4,436 lb)
Start of mission
Launch date7 December 1968, 08:40:09 (1968-12-07UTC08:40:09) UTC
RocketAtlas SLV-3C Centaur-D
Launch siteCape Canaveral LC-36B
End of mission
DisposalTelescope issues
DeactivatedFebruary 1973 (1973-03)
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee altitude768 kilometres (477 mi)
Apogee altitude777 kilometres (483 mi)
Inclination35.0 degrees
Period100.30 minutes
Epoch6 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.