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Two-Phase Thermal Switching System for a Small, Extended Duration Lunar Surface Science PlatformThis paper describes a novel thermal control system for the Warm Electronics Box (WEB) on board a small lunar surface lander intended to support science activities anywhere on the lunar surface for an extended duration of up to 6 years. Virtually all lander electronics, which collectively dissipate about 60 W in the reference mission, are contained within the WEB. These devices must be maintained below 323 K (with a goal of 303 K) during the nearly 15-earth-day lunar day, when surface temperatures can reach 390K, and above 263 K during the nearly 15-earth-day lunar night, when surface temperatures can reach 100K. Because of the large temperature swing from lunar day-to-night, a novel thermal switching system was required that would be able to provide high conductance from WEB to radiator(s) during the hot lunar day and low (or negligible) conductance during the cold lunar night. The concept that was developed consists of ammonia variable conductance heat pipes (VCHPs) to collect heat from WEB components and a polymer wick propylene loop heat pipe (LHP) to transport the collected heat to the radiator(s). The VCHPs autonomously maximize transport when the WEB is warm and autonomously shut down when the WEB gets cold. The LHP autonomously shuts down when the VCHPs shut down. When the environment transitions from lunar night to day, the VCHPs and LHP autonomously turn back on. Out of 26 analyzed systems, this novel arrangement was able to best achieve the combined goals of zero control power, autonomous operation, long life, low complexity, low T, and landed tilt tolerance.
Document ID
20100009810
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Bugby, David C. (ATK Space Systems, Inc. Beltsville, MD, United States)
Farmer, Jeffery T. (NASA Marshall Space Flight Center Huntsville, AL, United States)
OConnor, Brian F. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Wirzburger, Melissa J. (Johns Hopkins Univ. Laurel, MD, United States)
Abel, Elisabeth D. (Johns Hopkins Univ. Laurel, MD, United States)
Stouffer, Chuck J. (ATK Space Systems, Inc. Beltsville, MD, United States)
Date Acquired
August 25, 2013
Publication Date
February 23, 2010
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
M10-0073
Report Number: M10-0073
Meeting Information
Meeting: SPESIF - Space Propulsion and Energy Sciences International Forum/IASSPES
Location: Laurel, MD
Country: United States
Start Date: February 23, 2010
End Date: February 26, 2010
Sponsors: Johns Hopkins Univ.
Distribution Limits
Public
Copyright
Public Use Permitted.

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