California Launch Scheduled For November 1st
NASA's Wide-field Infrared Survey Explorer, or WISE, has been
assembled and is undergoing final preparations for a planned Nov. 1
launch from Vandenberg Air Force Base, Calif.
The mission will survey the entire sky at infrared wavelengths,
creating acosmic clearinghouse of hundreds of millions of objects
-- everything from the most luminous galaxies, to the nearest
stars, to dark and potentiallyhazardous asteroids. The survey will
be the most detailed to date in infrared light, with a sensitivity
hundreds of times better than that of its predecessor, the Infrared
Astronomical Satellite.
"Most of the sky has never been imaged at these infrared
wavelengths with this kind of sensitivity," said Edward Wright, the
mission's principalinvestigator at UCLA. "We are sure to find many
surprises."
On May 17, the mission's science instrument was delivered to
Ball Aerospace & Technologies Corp. in Boulder, Colo., where it
was attached to the spacecraft, built by Ball. The assembled unit
was then blasted by sound to simulate the effects of launch. Tests
for electronic "noise" in the detectors will be performed next.
The science instrument is a 16 inch telescope with four infrared
cameras. A cryostat, or cooler, uses frozen hydrogen to chill the
sensitive megapixel infrared detectors down to seven Kelvin (minus
447 degrees Fahrenheit). The instrument was built by Space Dynamics
Laboratory in Logan, Utah.
Among expected finds from WISE are hundreds of thousands of
asteroids in our solar system's asteroid belt, and hundreds of
additional asteroids that come near Earth. Many asteroids have gone
undetected because they don't reflect much visible light, but their
heat makes them glow in infrared light that WISE can see. By
cataloguing the objects, the mission will provide better estimates
of their sizes, a critical step for assessing the risk associated
with those that might impact Earth.
"We know that asteroids occasionally hit Earth, and we'd like to
have a better idea of how many there are and their sizes," said Amy
Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif., the
mission's deputy project scientist. "Whether they are dark or
shiny, they all emit infrared light. They can't hide from
WISE."
WISE will lift off from Vandenberg aboard a United Launch
Alliance Delta II rocket (file photo, above). It will orbit
Earth, mapping the entire sky in six months after a one-month
checkout period. Its frozen hydrogen is expected to last several
months longer, allowing WISE to map much of the sky a second time
and see what has changed.