Gas-Surface Interactions on Airless Bodies

Observation and Motivation

Volatiles at airless bodies, especially water (H2O), are key to several of NASA’s top-level goals, including: Origins, Workings, and Human Exploration. There are spacecraft and ground-based observations of airless bodies that are interpreted as volatiles, often water, at the surfaces of these bodies. However, at the Moon different data sets appear to disagree on exactly where volatiles are found. Laboratory investigations can reveal the fundamental behavior of volatiles interacting with regolith surfaces, aka “gas surface interactions”. Incorporation of the measured gas-surface interactions into exosphere models can help to better reproduce the measurements of exospheres, which enables better prediction of accumulation of volatiles into cold traps.

A second motive for exploring gas-surface interactions at airless bodies is to understand how robotic and/or human activities on the lunar surface alter the surface materials. Key questions include: what is the level and nature of contamination by exhaust from landing and from surface operations? What is the rate and character of volatiles released from the regolith by landing and by surface operations?

Our Effort

We are implementing novel approaches to quantifying gas-surface interactions in progressively more Lunar-like environments and operational scenarios.