The thermal control system for a network mission on Mars: The experience of the Netlander mission

Kurzfassung

The Netlander mission wants to establish an operating network of stations on the surface of Mars. Each one of four identical landers is equipped with science payloads dedicated to study the atmosphere and geosphere of Mars; operating together their objective is to investigate the Martian meteorology, ionosphere, ground and subsurface. Landing locations spread over two hemispheres and a mission duration of one Martian year, expose the surface modules and its sensitive electronics to a wide range of hostile conditions. Additional constraints come from the transporting spacecraft, where heat can be exchanged only across small interfaces. The purpose of the thermal control system is to maintain nevertheless the electronics and battery temperatures within a narrow band. Contrasting demands of reduced heat leaks and effective dump of surplus heat require new technologies and advanced design concepts to be satisfied under strict mass limits imposed. The paper describes the design, development and testing activities of a thermal control concept including high-performance insulation combined with an innovative loop heat pipe system. Extensive thermal analyses have been run and hardware has been built, qualified and tested. Results of the test are fairly positive, even in presence of some problematic issues. A post-fit numerical simulation has been initiated but further developments are needed.