Open Access

ARTICLE

ASETS-II OSCILLATING HEAT PIPE SPACE FLIGHT EXPERIMENT: THE FIRST SIX MONTHS ON ORBIT

by

a First U.S. Air Force Research Laboratory, Kirtland Air Force Base, NM, 87117, United States
b Applied Technology Associates, Albuquerque, NM, 87123, United States

* Corresponding Author: Email:

Frontiers in Heat and Mass Transfer 2019, 12, 1-7. https://doi.org/10.5098/hmt.12.24

Abstract

On September 7th, 2017 the U.S. Air Force Research Laboratory launched the second Advanced Structurally Embedded Thermal Spreader (ASETSII) flight experiment to space on Orbital Test Vehicle 5. The ASETS-II experiment is made of three low-mass, low-cost oscillating heat pipes (OHPs) and an electronics/experiment control box. The three primary science objectives of the experiment are to measure the initial on-orbit thermal performance, to measure long duration thermal performance, and to assess any lifetime degradation. The three OHPs on ASETS-II are of varying configuration (center heating with single- and double-sided cooling) and working fluids (butane and R-134a) in order to isolate specific performance parameters of interest. OHP #3 was specifically designed in order to explore the operating limits on OHP operation in microgravity without requiring excessive operating temperature or pressure. Data collected during the first 6 months of on-orbit operations are presented in this paper. It is shown that each OHP performed as expected, where on-orbit data for OHPs #1 and #2 mirrored ground-truth performance, and the OHP #3 on-orbit maximum operating evaporator temperature increased from ground-truth. The OHPs experienced no significant hysteresis effects and OHP #1 performed successfully in six-week long continuous operation.

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