| Launch Date |
1990 |
2007 |
|
| Mirror Size |
2.4 meters
(94 inches) |
4 to 8 meters
(156 to 312 inches) |
|
| Weight |
24,200 lbs. |
6,600 lbs. |
|
| Lifetime Cost |
$6 billion (1990) |
$900 million (1996) |
|
| Orbit |
Astronaut-serviceable, low-Earth orbit |
L2, 1x3 AU elliptical, or other non-serviceable orbit |
|
| Mission |
Ultraviolet, optical, and near-infrared astronomy with stable mirror and
multiple instruments |
Infrared astronomy with adjustable mirror and fewer integrated instruments |
|
| Observing Mode |
Mixed-duration observations |
Long periods of dedicated observation |
|
| Control and Tracking |
Frequent, complex command from multiple ground stations using NASA's geosynchronous
communications satellites |
Single dedicated ground station with high levels of spacecraft autonomy |
|
| New Technologies |
Low-noise, large-format CCDs ultra-low-noise, high-sensitivity gyros; first
significant civilian use of graphite epoxy structures for thermal stability
|
Ultra-lightweight optics; large-format, low-noise infrared detectors
and precise actuators that work at cryogenic temperatures
|
|
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