Interdisciplinary exploration science enabled by lunar landers: AstroLEAP sciences

The Moon is a unique and accessible target that hosts a distinctive space environment. It provides an opportunity to investigate fundamental physics associated with interactions with the undisturbed solar wind, magnetosheath, and magnetosphere. During disturbed space weather events, the lunar environment is influenced by hot plasma within the coronal mass ejections or high-energy particles such as solar energetic particles or cosmic rays. In the absence of an intrinsic magnetic field and a collisional atmosphere, the solar wind directly impacts the lunar surface, resulting in a plasma–regolith interaction, the physics of which remains poorly explored.

 

The interaction also sputters surface volatiles, producing the exosphere, a fragile gaseous environment surrounding the Moon. Space plasma may also contribute to the formation of surficial water, which can subsequently be released into the exosphere or space by meteoroid impacts. However, direct observational evidence for the production, circulation, and accumulation of such species remains highly limited. In addition, the Moon has localized magnetic anomalies that modify the incident plasma flow and, consequently, the near-surface environment. These disturbances are known as mini-magnetospheres, the smallest magnetospheres known. Local disturbances from environmental changes (electromagnetic fields, illumination, and their temporal variations) can induce significant dust lofting. Lunar dust poses a major hazard to human and robotic explorers. It is adhesive, potentially toxic, and easily mobilized. Dust particles can easily infiltrate electronics systems and spacesuits, and are significantly influenced by near-surface electric and magnetic fields. Furthermore, since the beginning of the space age, the lunar environment has been increasingly altered by human activities. Planned or ongoing exploration is expected to accelerate this anthropogenic modification. Quantifying the lunar environment is therefore urgently required to distinguish between its (near-)pristine state and its altered conditions on a decadal time scale.

 

In this presentation, we provide an overview of the multidomain physical processes—both natural and anthropogenic— that occur at the lunar surface in the context of future lunar surface missions.  We identify key open scientific questions concerning the lunar space environment and outline the measurements required to address them. These measurements are considered within the framework of the European scientific payload package concept, AstroLEAP (Lunar Environment Analysis Package), which is under study by ESA and the science community.