Framework for Coordinated Efforts in the Exploration of Volatiles in the South Polar Region of the Moon

Abstract:

The robotic exploration of the lunar south polar region and the ground truthing of polar volatiles is one of the next steps of NASA’s Artemis program, which aims to return humans to the Moon by 2024 with the support of other space agencies and private companies. The cadence of lander or rover missions leaving for the lunar surface may be as high as two per year in the near future. While various remote sensing measurements have inferred the presence of water ice in the lunar south polar region since the 1990s, it is only in 2018 that the first unambiguous regional (yet spatially resolved) detection of surficial water ice was achieved using the Moon Mineralogy Mapper data. It revealed that surficial water ice is present in many permanently shaded regions (PSRs).

Here we use these recent measurements, along with various other remote sensing datasets, to identify the most promising south polar sites to ground truth polar volatiles and provide a framework for coordinated efforts in the exploration of volatiles in the lunar south polar region. We characterize the water ice bearing PSRs (hydrogen, slope, temperature, illumination conditions), identify nearby potential landing site, and characterize the mobility between the landing sites and water ice bearing PSRs. We use the derived characteristics of the water ice bearing PSRs to determine which PSRs should preferentially be explored given different mission goals such as sampling the highest concentration of volatiles, characterizing the lateral or vertical distribution of volatiles, or obtaining the fastest recovery of a contingency sample.

We identified approximately 40 water ice bearing PSRs that show the greatest promise of answering these mission goals, allowing for many missions to be undertaken. We propose potential traverses to three of these PSRs in the scenario of a short (20-50 km), a medium (~100 km), and a longer mission (~300 km), according to the different capabilities of potential rovers and instruments. The 20-km mission is, for example, compatible with the NASA VIPER rover.

With the variety of water ice bearing PSRs we characterized, our study can support mission planning when considering specific mission goals or constraints, or conversely it could help in designing missions based on a location of interest.