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A brief history and the future of the Hubble Space
Telescope
The Hubble Space Telescope solves the problems caused
by viewing the universe through
the turbulent blanket of air that surrounds the earth. Hubble solves
these problems by “living” in orbit
around the earth and outside that blanket of air. Before its launch,
astronomers had not been able
able to take pictures of deep space with such clarity.
It took a long time, from the conception of the telescope
in 1948 to its realization and its current
excellence. The launch on April 24, 1990 , put the telescope in an elliptical
orbit above the earth.
There was great excitement when the first image were sent to earth,
but it soon became obvious
that the main mirror had an error in its shape that was blurring the
images. A mission by the space shuttle, Discovery, added an optical
correction called “COSTAR” that brought the telescope to
full clarity.
The great cost and the technological challenge of developing
telescopes in space is being met by
a joint effort between NASA and the European Space Agency. Since that
time, several other space
telescopes have been launched, each with it’s own, special capabilities.
The Hubble Space Telescope
will be 17 years old in April of 2007. A space telescope is like a cat
in that both are “old” at the age
of 17. With age, the Hubble developed some serious problems, which now
greatly limit its use. When astronomers want to point the telescope
at an object of interest, the telescope is turned toward the object
and held there by gyroscopes. Some of those gyroscopes have died of
old age. The failure of another gyroscope will render the telescope
useless. The main camera has also failed.
The space telescope is above almost all the earth’s atmosphere,
but there are still enough
molecules of air that the telescope slows down just a tiny bit whenever
it hits one. When an object
orbiting the earth slows down, it also moves a little closer to earth.
As it moves closer to the earth,
the atmosphere becomes denser and the slowing force even er. At the
rate that the Hubble Space
Telescope is descending into the atmosphere, it will heat up from the
friction of the air and burn up
around the year 2011.
The loss of the Hubble Space Telescope would be a great loss
indeed. A mission to rescue
the HST is now planned for September 11, 2008. It will require two space
shuttles. The first, the
Atlantis, will visit the Space Telescope and push it, increasing its
speed and the height of its orbit.
Astronauts will also repair the camera and the gyroscopes. The second
space shuttle, Discover will
be ready for launch should the astronauts need to be rescued on this
difficult mission. It is hoped
that this mission will keep the Hubble functioning through 2013.
A new space telescope, the James Webb Space Telescope
(JWST), will be launched at about
the time the Hubble goes out of service. The JWST will not be able to
take pictures in visible and
ultraviolet light like the Hubble, but it will be far superior in its
ability to see in the infrared part
of the spectrum.
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Mark Voit 