Lunar Surface Science Workshop 2020 (LPI Contrib. No. 2241) 6015.pdf

SCIENCE IN EXTREME ENVIRONMENTS ON THE MOON AND ITS MOBILITY REQUIREMENTS. Pascal Lee1,2,3. 1SETI Institute, 2Mars Institute, 3NASA Ames Research Center, [email protected]

Summary: Accessing extreme environments on the Thus, robust robotic scouts capable of rapidly scout- Moon is critical for science, in particular for volatile ing out large areas of the Moon over ranges of 10s of studies. Mobility capable not only of extreme terrain ac- km in high latitude regions, including into and out of the cess, but of deep, rapid, and repeated insertion into ex- cold, dark, steep and rough interiors of PSRs and pits, treme environments, esp. large PSRs and pits, is re- are needed. Similarly, Artemis astronauts require pres- quired. In less extreme settings, high-efficiency mobile surized rovers capable of nimbly traversing 10s of km science strategies should be employed. to enable in-depth exploration of these polar regions. Extreme Environments: Where We Want To Go! GlobeTrotter (GT). GT is a concept for a universal The lunar poles, where H2O ice and other volatile con- all-terrain soft-walled robotic hopper for rapid, robust, centrations occur and where NASA aims to land astro- and low-cost exploration of the surface and subsurface nauts by 2024 (Lunar South Pole) are in rough and of the Moon, Mars, Phobos. Deimos, and small bodies. steep-sloped highland terrain, including many PSRs. A GT-Lunar or GTL system is currently under develop- Skirting PSRs, however, is not sufficient. Known sur- ment at JPL for extreme environment exploration on the face exposures of H2O ice and of other volatile concen- Moon [8] (Fig.1). GTL would rapidly and robustly ex- trations occur far (several km) into the interior of large plore vast areas via “leaps and bounds” and in- PSRs [1]. Candidate pits and caves at high latitudes on gress/egress pits and caves [8]. the Moon would also be permanently shadowed and cold enough to cold-trap H2O ice and other ices [2-5]. The settings in which H2O and other volatiles are exposed on the Moon are, by lunar standards, extreme environments. Beyond the challenge of topography (slopes and terrain roughness), these environments typ- ically require km-scale distances to be traversed, sub- stantial total dwell time in permanent shadow (with low temperatures and no solar power inside PSRs or high latitude caves), and comms restrictions to overcome. Scale of Scientific Exploration Required. Lunar Figure 1: GlobeTrotter-Lunar (GTL) could traverse halfway polar terrains present significant diversity in terms of around Shackleton Crater (D~20 km; z~4 km) in 10 days, and reach its bottom in 2 more days, investigating 3 terrain classes relationship between the 3D distribution of H2O ice and and their volatile concentrations along the way. GTL could physical conditions prevailing at the surface and in the also rapidly and robustly ingress/egress pits and caves. subsurface. Moye & Lee [6] show that the lunar polar terrains may be divided into different classes based on ATVs and Pressurized Rovers (PRs). Important combinations of the following key factors: a) whether lessons have been learned from the practice of or not they present detectable H at the surface or within Moon/Mars analog field science operations at the the top 1 m of the regolith, b) whether or not they are NASA Haughton-Mars Project on Devon Island, High located in PSRs, and c) whether or not thermodynamic Arctic. While individual ATVs (1 per astronaut) are rec- models predict that H2O ice would be stable within the ommended for optimum safety, flexibility, and produc- top few meters of the subsurface. This classification tivity in short-range (< 2 km range) unpressurized ex- helps understand the origin, evolution, and 3D distribu- ploration, PRs (at least 2 per traverse) are essential for tion of volatiles at the lunar poles, but also highlights longer range exploration, ideally with escorting ATVs. the spatial scale at which the polar regions must be ex- PRs may play an important role as temporary remote plored to understand their volatile history: several tens outposts. Also, they should be equipped with robotic of km [6,7]. arms operable in IVA mode, as most samples to be col- Speed of Mobility Required. In addition to the lected on the Moon will be, as on Apollo, float [9]. ability to traverse rough terrain over large distance Acknowledgments: Credit and thanks are owed to Ed scales and/or safely drop into pits, the exploration of Riedel, Laura Wilson Jones, and JPL team for the GT concept studies. PSRs and high latitude caves also imposes severe con- References: [1] Li et al. (2018). PNAS 115, 8907-8912. [2] straints on power and communications. Mobility sys- Lee, P. (2018). 49th LPSC, #2982. [3] Lee, P. (2018). 6th Europ. Lunar tems that can move nimbly and rapidly across the lunar Symp., #024. [4] Lee, P. et al. (2019) 50th LPSC, #3118. [5] Lee, P. landscape are required in order to minimize traversing 2020. 3rd Int’l. Planet. Caves Conf., #1066. [6] Moye, C. & P. Lee time to reach each target, and dwell time once a target 2020. 51st LPSC, #2594. [7] Lee, P. et al. 2020. LSSW-2020. [8] Lee, is reached. In addition, pits must be quickly exitable. P. et al. 2020. 51st LPSC, #2917. [9] Lee, P. et al. 2012. Earth & Space.