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SLAC (Stanford Linear Accelerator Center) and NASA are
building the satellite that will transport to outer space the
'grand observatory' for mapping gamma-ray bursts. This telescope
known as GLAST, acronym for Gamma-ray Large Area Space
Telescope, will deliver 50x the resolution of the existing EGRET
project and will probe the mechanisms of particle acceleration,
investigate dark matter and the early Universe, and advance
science's knowledge of black holes.
The telescope will collect incoming gamma-ray signals from
outer space and feed them into a 850,000 channel data
acquisition system. The system will sift through the data,
determining what looks promising and what should be discarded.
When an interesting signal is detected, the system will orient
the telescope to face the source.
The 300-watt data acquisition system will be cooled by heat
pipes controlled by shutoff valves that automatically thermally
stabilize the electronics at approximately 15 deg. C. The heat
pipes will transfer operational heat from the electronics to
solar panel radiators for dissipation into space. The goal is to
hold system temperature to within +/- 1 deg. C, because large thermal
gradients can cause bending and warping of the detectors. But
designers also must prepare for the worst. If one of the 8
square meter solar arrays fails to open, or if a heat pipe
fails, temperatures could vary anywhere -40 deg C. to 55 deg.
C.
To verify the system's thermal design across the full
temperature spectrum, SLAC enlisted Daat Research Corp.
consulting services. Daat built accurate and fast Coolit
simulations based on imported SolidWorks models and searched for
potential hot spots in each of the system's 12 electronic
modules. The Coolit analyses proved the Gamma-ray Large Area
Space Telescope would handle even the worst-case conditions.
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