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Thermal Design and Analysis of a Multi-Stage 30K Radiative Cooling System for EPICThe Experimental Probe of Inflationary Cosmology (EPIC) is an implementation of the NASA Einstein Inflation Probe mission, to answer questions about the physics of Inflation in the early Universe by measuring the polarization of the Cosmic Microwave Background (CMB). The mission relies on a passive cooling system to cool the enclosure of a telescope to 30 K; a cryocooler then cools this enclosure to 18 K and the telescope to 4 K. Subsequently, an adiabatic demagnetization refrigerator further cools a large focal plane to approx.100 mK. For this mission, the telescope has an aperture of 1.4 m, and the spacecraft's symmetry axis is oriented approx. 45 degrees relative to the direction of the sun. The spacecraft will be spun at approx. 0.5 rpm around this axis, which then precesses on the sky at 1 rph. The passive system must both supply the necessary cooling power for the cryocooler and meet demanding temperature stability requirements. We describe the thermal design of a passive cooling system consisting of four V-groove radiators for shielding of solar radiation and cooling the telescope to 30 K. The design realizes loads of 20 and 68 mW at the 4 K and 18 K stages on the cooler, respectively. A lower cost option for reaching 40 K with three V-groove radiators is also described. The analysis includes radiation coupling between stages of the radiators and sunshields, and parasitic conduction in the bipod support, harnesses, and ADR leads. Dynamic effects are also estimated, including the very small variations in temperature due to the scan motion of the spacecraft.
Document ID
20150009145
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
External Source(s)
Authors
Chui, Talso
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Bock, Jamie
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Holmes, Warren
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Raab, Jeff
(Northrop Grumman Aerospace Systems Redondo Beach, CA, United States)
Date Acquired
June 1, 2015
Publication Date
June 23, 2009
Subject Category
Fluid Mechanics And Thermodynamics
Meeting Information
Meeting: Space Cryogenics Workshop
Location: Arcadia, CA
Country: United States
Start Date: June 23, 2009
End Date: June 25, 2009
Sponsors: Northrop Grumman Aerospace Systems
Distribution Limits
Public
Copyright
Other
Keywords
Space
Cryogenics
cooling

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