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Hubble Tune-Up Plans Detailed

January 8, 2008

AUSTIN, Texas — The orbiting space telescope that
just won’t quit collecting gobs of celestial data well beyond its expected
twilight is set for a major tune-up and upgrade, NASA scientists announced
today here at a meeting of the American Astronomical Society.

The fifth
servicing mission will also be the Hubble Space Telescope’s last.

Word here
today is that the Space Shuttle Atlantis would lift off in August with a crew
of seven astronauts, a cargo of equipment, tools and new instruments for Hubble.

Orbiting at
about 350 miles (563 kilometers) above Earth, Hubble is above the atmosphere and doesn’t
have to contend with the shifting pockets of air that distort images made by ground-based
telescopes. This atmospheric distortion is the reason stars appear
to twinkle
.

The clear
view has meant, for one, that over Hubble’s 16-plus years in orbit, it has sent
back a spectacular
photo album
of sci-fi-like jets from black holes, galaxies in all stages of
evolution, and snapshots of planets in our own solar system.

“Hubble
is, without exaggeration, a national treasure,” said NASA’s Alan Stern,
associate administrator for the Science Mission Directorate in Washington, D.C., “and all of NASA is looking forward to seeing it receive this
tune-up and upgrade.”

The
public’s love for Hubble along with political pressure have both played rolls
in NASA’s decision to service the observatory, a mission deemed risky compared
to other shuttle ventures.

Hubble
Hugger

During the
11-day shuttle mission, and five spacewalks, astronauts will install two new
science instruments plus a set of gyroscopes to help stabilize the telescope,
as well as batteries and thermal blankets to keep the observatory operating
until at least 2013.

Leading the
spacewalks will be self-labeled “Hubble Hugger,” John Grunsfeld, who told SPACE.com
last year
he would like to be on the mission.

“As
both an astronaut and an astronomer, the opportunity to go back to Hubble is
more than a dream come true,” said Grunsfeld, who will be the mission’s
lead spacewalker. However, Grunsfeld notes, “This mission promises to be
quite challenging.”

For
instance, astronauts will attempt the first-ever on-orbit repair of two
existing instruments, the Space Telescope Imaging Spectrograph (STIS) and the
Advanced Camera for Surveys (ACS).

Installed
on Hubble in February 1997, the STIS separates incoming light into its
constituent colors, giving astronomers a chemical map of a distant object.
Since deployed, STIS has been critical in the confirmation of black holes at
the centers of galaxies, made the first discovery of an atmosphere around an
exoplanet and helped confirm the age of the universe.

Better
science

The two
additions to Hubble’s science cargo include the Wide Field Camera 3, a
“panchromatic” camera, and the Cosmic Origins Spectrograph (COS).

The COS will probe the large-scale structure of the universe, the so-called cosmic
web
, in which strands of galaxies transect seemingly empty space like a
gargantuan three-dimensional spider web. It is the universe’s invisible
“glue” called dark matter, which is thought to make up about 85
percent of all matter in the universe, that astronomers say gives the web its
structure.

Astronomers
infer the existence of the cosmic web just as a child might know a Christmas
tree exists by looking at the colorful lights that outline its branches.
Instead of little bulbs, the stars and galaxies trace out the cosmic web.

In the end,
scientists expect to breathe new and improved life into Hubble.

“Our
goal for this mission is to leave Hubble at the apex of its scientific
capabilities,” said Leckrone, Hubble senior project scientist at NASA’s Goddard Space Flight Center. The addition of new instruments along with repairs of others
should give astronomers a full “tool box” for resolving many cosmic
conundrums, Leckrone said.


Source: imaginova



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