Heat pipes for thermal control of ISS solar battery drive

This paper considers design and testing aspects of ammonia axial grooved heat pipes (AGHPs) made of aluminum alloy 6063 intended for cables thermal control of the solar battery drive integrated into the International Space Station. The heat removal system includes four heat pipes with a diameter of 10 mm and length of 2 m. Each heat pipe shall transfer 50 W in temperature range of 0–50 °C with a maximum temperature differential of 5 °C. Great attention is paid to the requirements of reliability and prolonged lifetime (19 years: 15 years of operation and four years of storage). For this purpose several heat pipes made 10 years ago of the same initial materials were subjected to accelerated lifetime testing (testing duration is 4250 h at a temperature of 100 °C). AGHP performance obtained before and after accelerated testing and also acceptance test results are presented in this paper. The determined data shows that AGHP performance is in compliance with the statement of work requirements.