The Passive Regolith Sampler: From Concept to Delivery to the Lunar Surface

Abstract

This paper outlines the development and testing of two light-weight, low-cost, passive sensors developed by the MIT Space Enabled Research Group that were delivered to the moon in 2023 onboard the Rashid-1 rover as part of the Emirates Lunar Mission. The Passive Regolith Sampler (PRS) is a simple device mounted to the wheels of the rover, containing an aluminum tray with a cover plate of perforated holes of varying size and spacing. The device uses the motion of the rover wheel to press the device into the lunar surface, capturing small samples of lunar regolith in the holes. The Passive Wax Thermometer (PWT) is a collection of 10 wax samples, contained in individual capsules covered with sapphire windows. Each wax sample is an alkane with a different melting temperature determined by its chemical formula. Each wax sample undergoes temperature-dependent changes in opacity, providing a method for inferring temperature via image analysis. In preparation for lunar surface operations, the Space Enabled team performed a series of laboratory experiments and analytical analyses aiming to replicate conditions expected to be encountered during the mission. These experiments and analyses explored the physical mechanisms of the rover/regolith interaction, the lighting and thermal conditions at the landing site, and the quality of images captured from the rover mast camera. This paper outlines the results of these experiments and analyses, and their influence on the design and operations planning for the two payloads. Due to landing anomalies, the 2023 mission did not complete lunar surface operations; further work is planned to explore future operational opportunities.