SAS (Small Astronomy Satellite)
A series of NASA spacecraft placed in orbit in the 1970s to observe celestial
X-ray and gamma-ray
sources. All were launched from San Marco.
SAS-1
The first Earth-orbiting mission dedicated to X-ray astronomy. Launched
from the San Marco platform off the coast of Kenya on the seventh anniversary
of Kenyan independence, SAS-1 was renamed "Uhuru" which is Swahili for "freedom."
It carried out observations in the 2-20 keV energy range, discovering 200
X-ray sources and finding evidence of the first known black hole. It stopped
operating on April 5, 1979. Also known as Explorer
42.
SAS-2
A gamma-ray astronomy satellite sensitive in the energy range 20 MeV-1 GeV.
SAS-2 provided the first detailed look at the gamma-ray sky, established
the high energy component of diffuse celestial radiation, and enabled a
correlation of the gamma-ray background with galactic structural features.
On June 8, 1973, a failure of the spacecraft's low-voltage power supply
ended its mission. Also known as Explorer 48.
SAS-3
An X-ray astronomy satellite with three major scientific objectives: to
fix the location of bright X-ray sources to an accuracy of 15 arcseconds,
to study selected sources over the energy range 0.1-55 keV, and to search
the sky continuously for X-ray novae, flares, and other transient (short-lived)
phenomena. It stopped operating in 1979. Also known as Explorer 53.
| spacecraft |
launch date |
launch vehicle |
orbit |
mass (kg) |
| SAS-1 (Uhuru) |
Dec. 12, 1970 |
Scout B |
521 × 570 × 3° |
143 |
| SAS-2 |
Nov. 15, 1972 |
Scout D |
526 × 526 × 1° |
185 |
| SAS-3 |
May 7, 1975 |
Scout F |
498 × 507 × 3° |
195 |
Related entry
X-ray satellites
Related category
SATELLITES
AND SPACE PROBES
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