Initial Evaluation of On-orbit Experiment of Loop Heat Pipe on ISS



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49th International Conference on Environmental Systems


A loop heat pipe (LHP) is a passive two-phase heat transfer device that utilizes the evaporation and condensation of a working fluid to transfer heat and capillary force to circulate the fluid. The LHP can transport much heat for a long distance against gravity and has many other excellent characteristics, such as high controllability of operating temperature and a shutdown function. LHP was invented in Russia in the early 1980’s and started being applied for space missions for more that 20 years. Although research and development of LHPs has been conducted for a long time in Japan, a Japanese LHP has not yet been employed in a practical mission. In this study, LHPs for space application were developed. As a result of on-ground test of LHPs, it is confirmed that LHPs can satisfy the needed functional and performance requirements (e.g. maximum heat transport rate, minimum required heat load for start-up, operating temperature control and shutdown function). To adopt the LHP to the thermal control system of spacecraft, the thermal characteristic under micro-gravity conditions should be examined in advance. An on-orbit experiment of a LHP radiator system (LHPR) on the International Space Station (ISS) was conducted from October 9th to November 21st, 2018. This paper describes the results of an initial evaluation of this on-orbit experiment of a LHP radiator system.


Atsushi Okamoto, Japan Aerospace Exploration Agency (JAXA), Japan
Takeshi Miyakita, Japan Aerospace Exploration Agency (JAXA), Japan
Hosei Nagano, Nagoya University, Japan
ICES201: Two-Phase Thermal Control Technology
The 49th International Conference on Environmental Systems as held in Boston, Massachusetts, USA on 07 July 2019 through 11 July 2019.


loop heat pipe, on-orbit experiment, thermal control, satellite, heat transfer