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Proceedings Paper

Performance demonstration of hydrogen advanced loop heat pipe for 20-30K cryocooling of far infrared sensors
Author(s): Triem T. Hoang; Tamara A. O'Connell; Jentung Ku; C. Dan Butler; Theodore D. Swanson
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Paper Abstract

The James Webb Space Telescope (JWST) program have identified the need for cryogenic cooling transport devices that (i) provide robust/reliable thermal management for Infrared (IR) sensors/detectors in the temperature range of 20-30K, (ii) minimize vibration effects of mechanical cryocoolers on the instruments, (iii) reduce spatial temperature gradients in cryogenic components, and (iv) afford long continuous service life of the telescope. Passive two-phase capillary cooling technologies such as heat pipes, Loop Heat Pipes (LHPs), and Capillary pumped Loops (CPLs) have proven themselves capable of performing necessary thermal control functions for room temperature applications. They have no mechanical moving part to wear out or to introduce unwanted vibration to the instruments and, hence, are reliable and maintenancefree. However, utilizing these capillary devices for cryogenic cooling still remains a challenge because of difficulties involving the system start-up and operation in a warm environment. An advanced concept of LHP using Hydrogen as the working fluid was recently developed to demonstrate the cryocooling transport capabilities in the temperature range of 20-30K. A full-size demonstration test loop − appropriately called H2-ALHP_2 − was constructed and performance tested extensively in a thermal vacuum chamber. It was designed specifically to manage "heat parasitics" from a warm surrounding, enabling it to start up from an initially supercritical state and operate without requiring a rigid heat shield. Like room temperature LHPs, the H2-ALHP transport lines were made of small-diameter stainless steel tubing that are flexible enough to isolate the cryocooler-induced vibration from the IR instruments. In addition, focus of the H2-ALHP research and development effort was also placed on the system weight saving for space-based applications.

Paper Details

Date Published: 25 August 2005
PDF: 10 pages
Proc. SPIE 5904, Cryogenic Optical Systems and Instruments XI, 590410 (25 August 2005); doi: 10.1117/12.618318
Show Author Affiliations
Triem T. Hoang, TTH Research, Inc. (United States)
Tamara A. O'Connell, TTH Research, Inc. (United States)
Jentung Ku, NASA Goddard Space Flight Ctr. (United States)
C. Dan Butler, NASA Goddard Space Flight Ctr. (United States)
Theodore D. Swanson, NASA Goddard Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 5904:
Cryogenic Optical Systems and Instruments XI
James B. Heaney; Lawrence G. Burriesci, Editor(s)

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