Other Names:
HST
Space Telescope
20580
Launch Date: 25. 4. 1990
On-orbit dry mass: 11600.00kg
Nominal Power Output: 2400.00 W
Description
The Hubble Space Telescope (HST) is a cooperative
program of the European Space Agency (ESA) and the National Aeronautics and Space
Administration (NASA) to operate a long-lived space based observatory for the benefit of
the international astronomical community. The first dream of the HST was in the 1940's,
but designed in the 1980's and 90's. From the beginning, HST was designed to be a
different type of mission for NASA -- a long-term space based observatory. To accomplish
this goal and protect the spacecraft against instrument and equipment failures, NASA had
always planned regular servicing missions. HST is a 2.4-meter reflecting telescope, which
was deployed, in low Earth orbit (600 kilometers) by the crew of the space shuttle
Discovery on April 25th 1990. The whole craft measures 13.1-meters from end-to-end and
4.3-meters in diameter at its widest point and has a roughly cylindrical shape. HST's
current complement of science instruments include three cameras, two entire range and fine
guidance sensors (mostly used for astrometic observations). Because of HST's location
above the Earth's atmosphere, these science instruments
can produce high-resolution images of astronomical objects. The resolution of the HST
produced images can be up to ten times more detailed than these made by a ground based
telescope!
The power on board the HST was produced by two 2.4 x 12.1m solar panels. The power generated by the arrays was also used to charge six nickel-hydrogen batteries which provided power to the spacecraft during the roughly 25 minutes per orbit in which HST was within the Earth's shadow.
Communications with the satellite were maintained with the TDRS satellites.
Observations taken during the time when neither TDRS was visible from the spacecraft were
recorded on tape recorder and dumped during periods of visibility. The spacecraft also
supported real-time interactions with the ground system during times of TDRS visibility,
enabling observers to make small offsets in the spacecraft pointing to perform their
observations.