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Cryocooler
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The
GeDs are cooled on-orbit by a single electro-mechanical
cryocooler. Recently, under contract to NASA/GSFC, Sunpower Inc.
has developed an inexpensive single stage, integral
(counterbalanced) Stirling cycle cooler which can provide up to
4W of cooling at 77 K, with an input of 100W. This M77
cryocooler has been designed for operational lifetimes greater
than 50,000 hours, using a gas bearing/flexure system to prevent
contact of moving parts. In extensive studies over the past two
years at GSFC, M77 coolers have been vibrated to the GEVS
mandated 14.1 Grms, run under thermal vacuum conditions from
-25C to +30C, and life-tested already (continuing) for
~>10,000 hrs. Monitoring during these tests showed no
internal contamination of the working gas. Units already tested
at GSFC are fully qualified for flight, and will be used for
HESSI. More
Diagrams and Illustrations... |
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