[meteorite-list] NASA's WISE Space Telescope Jettisons Its Cover

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 30 Dec 2009 10:07:58 -0800 (PST)
Message-ID: <200912301807.nBUI7xh3000690_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2009-206

NASA's WISE Space Telescope Jettisons Its Cover
Jet Propulsion Laboratory
December 29, 2009

Engineers and scientists say the maneuver went off without a hitch, and
everything is working properly. The mission's "first-light" images of
the sky will be released to the public in about a month, after the
telescope has been fully calibrated.

"The cover floated away as we planned," said William Irace, the
mission's project manager at NASA's Jet Propulsion Laboratory, Pasadena,
Calif. "Our detectors are soaking up starlight for the first time."

WISE will perform the most detailed infrared survey of the entire sky to
date. Its millions of images will expose the dark side of the cosmos --
objects, such as asteroids, stars and galaxies, that are too cool or
dusty to be seen with visible light. The telescope will survey the sky
one-and-a-half times in nine months, ending its primary mission when the
coolant it needs to see infrared light evaporates away.

WISE launched on Dec. 14 from Vandenberg Air Force Base in California.
Once it was thoroughly checked out in space, it was ready to "flip its
lid."

The cover served as the top to a Thermos-like bottle that chilled the
instrument -- a 40-centimeter (16-inch) telescope and four infrared
detector arrays with one million pixels each. The instrument must be
maintained at frosty temperatures, as cold as below 8 Kelvin (minus 447
degrees Fahrenheit), to prevent it from picking up its own heat, or
infrared, glow. The cover kept everything cool on the ground by sealing
a vacuum space into the instrument chamber. In the same way that Thermos
bottles use thin vacuum layers to keep your coffee warm or iced tea
cold, the vacuum space inside WISE stopped heat from getting in. Now,
space itself will provide the instrument with an even better vacuum than
before.

The cover also protected the instrument from stray sunlight and extra
heat during launch.

At about 2:30 p.m. PST (5:30 p.m. EST), Dec. 29, engineers sent a
command to fire pyrotechnic devices that released nuts holding the cover
in place. Three springs were then free to push the cover away and into
an orbit closer to Earth than that of the spacecraft.

Scientists and engineers are now busy adjusting the rate of the
spacecraft to match the rate of a scanning mirror. To take still images
on the sky as it orbits around Earth, WISE will use a scan mirror to
counteract its motion. Light from the moving telescope's primary mirror
will be focused onto the scan mirror, which will move in the opposite
direction at the same rate. This allows the mission to take
"freeze-frame" snapshots of the sky every 11 seconds. That's about 7,500
images a day.

"It's wonderful to end the year with open WISE eyes," said Peter
Eisenhardt, the mission's project scientist at JPL. "Now we can synch
WISE up to our scan mirror and get on with the business of exploring the
infrared universe."

WISE is scheduled to begin its survey of the infrared heavens in
mid-January of 2010.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science
Mission Directorate, Washington. The principal investigator, Edward
Wright, is at UCLA. The mission was competitively selected under NASA's
Explorers Program managed by the Goddard Space Flight Center, Greenbelt,
Md. The science instrument was built by the Space Dynamics Laboratory,
Logan, Utah, and the spacecraft was built by Ball Aerospace &
Technologies Corp., Boulder, Colo. Science operations and data
processing take place at the Infrared Processing and Analysis Center at
the California Institute of Technology in Pasadena. Caltech manages JPL
for NASA. More information is online at http://www.nasa.gov/wise and
http://wise.astro.ucla.edu .

Whitney Clavin 818-354-4673/818-354-5011
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin at jpl.nasa.gov

2009-206
Received on Wed 30 Dec 2009 01:07:58 PM PST