The Lunar Meteoroid Monitor (LMM)

Meteoroid impacts play a critical role in sustaining the tenuous lunar atmosphere and providing delivery, transport, and loss mechanisms for volatiles that are relevant for in situ resource utilization. The Lunar Ejecta and Meteorite (LEAM) experiment, placed on the surface during the Apollo 17 mission had the science objectives to monitor incoming meteoroids, however it was swamped, most likely, by slow-moving highly charged lunar fines. In addition, LEAM struggled with thermal issues, and it could not be operated during the lunar day. This presentation is to report on the status of a new Lunar Meteoroid Monitor (LMM) instrument to provide the capability for the long-term continuous monitoring of meteoroids bombarding the lunar surface. The LMM instrument is a dust impact detector. The sensors are thin, permanently polarized polyvinylidene fluoride (PVDF) plastic films that generate an electrical charge when dust particles penetrate their surface. PVDF based dust detectors from the University of Chicago have been successfully flown onboard the Vega 1& 2, Stardust, ARGOS, and the Cassini missions. More recent versions have been developed at the University of Colorado for the New Horizons and the Aeronomy of Ice in the Mesosphere (AIM) missions. LMM is a large surface area deployable instrument. Once deployed, LMM consists of a top foil of 6 and a bottom foil of 28 micron thick PVDF sheets. The top foil is penetrated by most of the incoming particles that are subsequently either stopped in the bottom foil or penetrate that that too. The impact generated charges are functions of both the particles mass m and the speed v. LMM is designed for deployment on the lunar surface from a stationary lander that provides power and communication. The ongoing development includes: a) the deployable structure for the large area detector, while providing a compact configuration for stowing through launch; b) low-power electronics for impact detection and signal processing that enables maintaining continuous operation of LMM throughout the lunar night; and c) the thermal design for LMM that will enable the continuous operation over a lunar day, where the temperature extremes of the surface can vary over a range -170 °C to +120 °C. LMM is envisioned to be part of the payload for a series of Lunar Environmental Monitoring Stations (LEMS) deployed on the lunar surface.