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NASA announced that at 12:05 p.m. EDT, the Delta II rocket
easily lifted the GLAST spacecraft off the launch pad and the second firing of
the second-stage engine was confirmed as successful spacecraft separation.
GLAST is now on its own with its solar arrays deployed and placed into a
circular orbit 350 miles above the Earth, prepared to monitor the universe and
the mysterious gamma-ray bursts.
GLAST is the first imaging gamma-ray observatory to survey
the entire sky every day. It will give scientists a unique opportunity to learn
about the ever-changing universe at extreme energies. GLAST’s mission is to
understand the mechanisms of particle acceleration in active galactic nuclei
(AGNs), neutron stars, and supernova remnants (SNRs) and to determine the
high-energy behavior of gamma-ray bursts (GRBs) and variable sources.
Although gamma rays can travel across the Universe they
cannot penetrate even the thinnest part of Earth’s upper atmosphere. Therefore,
the detectors need to be placed above the atmosphere. To accomplish this, GLAST
will be launched into circular orbit around Earth at an altitude of about 560
km (350 miles). This orbit is chosen to minimize the effects of charged
particles that surround Earth, and which would create additional unwanted
background signals in the detectors, while still ensuring the full mission
lifetime.
At that altitude, the observatory will circle Earth every 95 minutes.
In sky-survey mode, GLAST will be able to view the entire sky in just two
orbits, or about 3 hours.
Data analysis will be performed at two remote science
centers, located at the Stanford Linear Accelerator
Center, operated by Stanford University
for the U.S. Dept. of Energy, and at NASA’s Marshall Space Flight Center, in Huntsville, Alabama.
GLAST data goes to the GSSC and is then distributed to the science community.
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