Laboratory investigation of lunar impact flashes in support for ground and space observations.

With space agencies and private companies around the world expanding their activities in space, the Moon is now closer than ever before. NASA’s Artemis program missions are intended not only to return humans to the lunar surface, but also to establish a permanent presence there within the next decade. It is therefore essential to investigate the hazards present both in lunar orbit and on the surface in order to ensure astronaut safety. Impacts are among the most destructive processes in the Solar System and represent one of the major hazards on the lunar surface. Although catastrophic impacts, such as the asteroid event linked to the extinction of the dinosaurs, are extremely rare, the Earth–Moon system experiences a continuous flux of small meteoroids, ranging from decimetre-sized objects to dust particles.

Since the late 1990s, the lunar surface has been monitored to detect transient light phenomena produced during meteoroid hypervelocity impacts [1], commonly referred to as lunar impact flashes (LIFs). These observations have been conducted using small and medium-sized ground-based telescopes, with the aim of deriving the impact flux of centimetre- to decimetre-sized meteoroids [2–5]. In parallel, several detection and analysis techniques have been developed, depending on the observational setup (single- or dual-camera systems) and the scientific objectives of the observing teams [6,7]. Using data from NASA’s Lunar Reconnaissance Orbiter, several newly formed craters have been identified and linked to observed LIFs [2,8–11].

Observable impacts occur only every few hours, while more energetic events are even rarer and can only be detected under favourable observing conditions. Establishing a worldwide observing network is therefore essential to maximise monitoring time and improve detection statistics. The new Twin Impact Lunar Telescope (TILT) network will continuously monitor the Moon at visible and infrared wavelengths. The network will also support lunar seismology missions, including Chang'e 7, ESA’s LUMIO, NASA’s Farside Seismic Suite, and the South Pole Seismic Suite.

In preparation for these missions, and to support the interpretation of observations from LUMIO and the ground, we performed a series of laboratory impact experiments using the light-gas gun at the University of Kent to fire projectiles into lunar regolith simulants. The experiments were conducted over a range of impact velocities, while the resulting impact flashes were recorded using a custom-built spectrophotometric instrument with ten wavelength channels [10]. In this presentation, we will discuss our results.

 

Acknowledgments: This work is funded by STFC and UKSA grants. LUMIO is a mission funded under ESA’s General Support Technology Programme (GSTP) through the support of the national delegations of Italy (ASI), the United Kingdom (UKSA), Norway (NOSA), and Sweden (SNSA). The authors would like to acknowledge the support by the LUMIO Science Team.

 

References:

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