NASA's GLAST mission one step closer to launch (Forwarded)

Rob Gutro
Goddard Space Flight Center, Greenbelt, Md. April 11, 2007
301-286-4044

RELEASE NO. 07-12

NASA'S GLAST MISSION ONE STEP CLOSER TO LAUNCH

NASA's next major space observatory, the Gamma-ray Large Area Space
Telescope (GLAST), is one step closer to unveiling the mysteries of the
high-energy universe. Almost all the components have been assembled onto
the spacecraft, which will undergo a review this week before
environmental testing begins at the primary contractor, General Dynamics
Advanced Information Systems in Gilbert, Ariz.

GLAST will study the universe's most extreme objects, observing physical
processes far beyond the capabilities of earthbound laboratories.
GLAST's main instrument, the Large Area Telescope (LAT), operates like a
particle detector rather than a conventional telescope. It is 30 times
more sensitive (and even more at higher energies) than the best previous
missions, enabling it to detect thousands of new gamma-ray sources while
extending our knowledge of previously unidentified sources. For example,
it will study how some black holes accelerate matter to near light speed
and perhaps even reveal the nature of dark matter. The other instrument,
the GLAST Burst Monitor (GBM), will detect roughly 200 gamma-ray bursts
per year. Together with the LAT, the GBM will enable GLAST to make
gamma-ray burst observations spanning a factor of a million in energy.

"These two instruments and the spacecraft have now been integrated and
are working together as a single observatory," says GLAST project
manager Kevin Grady of NASA's Goddard Space Flight Center, Greenbelt,
Md.

"The observatory is getting ready for the final testing in the simulated
environment of space, so that any problems can be fixed to ensure that
it will work when we launch it," adds Kathleen Turner, the LAT program
manager at the United States Department of Energy, in Germantown, Md.
The Department of Energy helped build the LAT in collaboration with
other institutions in the United States, France, Italy, Japan, and
Sweden. NASA's Marshall Space Flight Center, Huntsville, Ala., built the
GBM in collaboration with institutes in Germany.

On April 11 and 12, 2007, an independent committee of scientists and
engineers commissioned by NASA will conduct a Pre-Environmental Review
(PER). This committee, chaired by Mark Goans of NASA Goddard, has been
monitoring the development of the mission over the past four years. This
review is expected to last two days, and will make sure that all
technical problems and anomalies have been resolved, and that the
4.7-ton spacecraft is ready to be "shake and baked."

Following the PER, environmental testing will begin. Each individual
subsystem has already passed its own round of environmental testing, but
this new set of procedures will make sure that the integrated
observatory can survive the rigors of launch and the harsh conditions of
space.

In the first test, called the Electro-Magnetic Interference test,
operators will bombard the spacecraft with electromagnetic radiation to
ensure that certain systems do not produce signals that interfere with
other systems. As project scientist Steve Ritz of NASA Goddard explains,
"If electrical noise from your beating heart causes a problem with your
brain, you'd want to know about it."

Next, GLAST will undergo mechanical tests, which involves exposure to
vibrations, shocks, and acoustic waves. The vibration test will make
certain the entire spacecraft can survive the shaking of a Delta II
Heavy rocket launch. With the tall spacecraft being shaken from its
base, some of the appendages will be exposed to accelerations up to 15
times the force of Earth's gravity. The shock test ensures it can
survive separation from the booster. The acoustic test examines if the
craft can survive the terrific roar of a Delta II launch. Engineers will
bombard the spacecraft with up to about 144 decibels of noise, louder
than being in close proximity to a jet aircraft.

Finally, the team will subject GLAST to the Thermal-Vacuum test, which
checks the spacecraft's ability to withstand the vacuum of space and the
extreme temperature swings it will experience as it goes in and out of
sunlight during each orbit. This procedure will last about six weeks,
the longest of all the environmental tests.

In mid-October, GLAST is scheduled to be flown to Cape Canaveral Air
Force Station, Fla., on a C5 airplane. The spacecraft is scheduled to be
launched into a low-Earth circular orbit no earlier than Dec. 14, 2007.

NASA's GLAST mission is an astrophysics and particle physics
partnership, developed in collaboration with the U.S. Department of
Energy, along with important contributions from academic institutions
and partners in France, Germany, Italy, Japan, Sweden, and the United
States.

For more information on GLAST, please visit on the Web:
http://glast.gsfc.nasa.gov


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