Freezing through the Lunar Night: A Power System Concept for Small Lunar Experiments to survive Multiple Day/Night Transitions

Abstract

In the wake of upcoming large-scale lunar exploration missions (e.g. ARTEMIS) and advances in medium-sized commercial cargo missions the availability of ride-share opportunities enables a new class of independent small payloads. The department of Avionic Systems of the Institute of Space Systems (German Aerospace Center, DLR) is currently developing an experiment to measure the electric field during the day/night transition of the moon (Lunar Surface Charging Experiment, LUCENT). For LUCENT to achieve the goal of capturing multiple transitions, it has to operate into and survive the lunar night. Furthermore, to minimize external disturbances it is designed as a standalone experiment of about 5 dm³ total volume. The combined requirements of small size and surviving the lunar night require a new approach for the overall design allowing the system to completely cool down. The scope of this paper is the design and development of a small-scale power system for long-term lunar surface operations as well as the supporting thermal tests of batteries, electronics and switches. Finally, a prototype to validate the operational scenario in terms of temperature cycling and lighting is presented. Although tailored for the application in the LUCENT experiment, this approach could be suitable for many small sensor systems that can tolerate low temperatures and limited night time operations.