Science Enables Exploration And Exploration Enables Science. Exploring The Lunar Polar Volatile Deposits
Introduction: Lunar orbital mission data have demonstrated the presence of Hydrogen deposits at the poles of the Moon, predominantly in permanently shaded regions (PSRs), although not all PSRs contain such deposits. Science & Exploration Synergies: A Lunar Polar Volatiles Explorer concept was explored during the last decadal survey  and the nature of polar volatiles was highlighted as an important science topic that should be addressed by future missions. There is a lot of international interest in these deposits because of their resource potential. Seven landed missions to the South Pole are scheduled between now and 2025. Only one of these is from the United States – Resource Pro-spector. Capable US missions to the surface at the po-lar regions of the Moon can return important science and exploration data and could foster a partnership between SMD-PSD and HEOMD-AES to build on the Resource Prospector mission and the Lunar Polar Vol-atiles Explorer concept . The Polar Volatile Deposit Environment: The richest deposits are found inside certain PSRs  (Fig. 1a,b) (South Pole: Cabeus, Haworth, Shackleton, No-bile. Fig. 1a); North Pole: just East of Whipple, Rhozhdestvenskiy U vicinity, western Rhozhdestven-skiy W, portions within and just East and West of Pea-ry; potentially western Hermite. Fig. 1b). These repre-sent some of the coldest places in the Solar System (30 K minimum ) and also many PSRs have steep slopes  requiring very capable rovers and/or novel exploration strategies to truly explore these deposits. Why Should We Explore Polar Volatile Depos-its? Science: understand the origin of such volatiles (endogenous vs. exogenous); potentially understand the lunar volatile cycle; investigate the delivery of vol-atiles to the inner Solar System; explore if the building blocks for life are present in the deposits. Exploration: define the distribution of such deposits within various PSRs; understand the form the volatiles are in; explore the regolith geotechnical properties of regolith at ex-tremely low temperatures; understand how easy/difficult the volatiles are to extract from the rego-lith; quantify the refining process for and transport and storage of potential life support consumables and rock-et fuels. Exploring Polar Volatile Deposits: Various strat-egies can be employed of varying complexity. 1. Low cost LCROSS-type missions to various PSRs. 2. Penetrators containing mass spectrometers de-ployed to larger PSRs (short-lived). 3. Short-lived static landers direct to a PSR. These could contain RTG-powered rovers. 4. Resource-Prospector-type rovers for short duration visits to accessible PSRs. 5. RTG-powered rovers that would land in sunlight and traverse into PSRs. 6. “Hoppers” to visit areas within a PSR and poten-tially visit several PSRs. Initial Data Needed: A variety of data is needed for both science and exploration. Data types include: • Elemental abundances and isotopic composition. • Variability both aerially and in the subsurface. • Regolith geotechnical properties. • Physical form (ice layer, ice-regolith mixture, etc.). • Environmental data. Instruments: Examples of instruments needed to investigate volatile deposits in PSRs are: IR-Vis-UV spectrometer(s), oven, mass spectrometer, drill (+/- coring capability), penetrometer, high-resolution cam-era(s). Other may be required depending on the mis-sion goals. Landing Sites: A strategy needs to be developed that includes a campaign to initially undertake in situ science at the different PSRs at both the South and North poles. For example, mission options 1 & 2 could be deployed to the large neutron suppression areas deep with in PSRs (e.g., Cabeus, Haworth, Shackleton, Nobile, West of Peary). Mission options 3 and 4 could be deployed to craters that are in partial shadow (e.g., Peary, western Hermite, western Rhozhdestvenskiy W). Mission option 5 is suggested for detailed PSR investigations if mission opportunities are limited and/or if rovers cannot enter the region. Importantly, investigating areas that exhibit some neutron suppres-sion but are occasionally in sunlight. This may remove the requirement for operating in extremely low tem-peratures while achieving most if not all science and exploration goals. An example landing site of this type would be Peary Crater. Technology Development: Rover development (building on MSL heritage), Hoppers will require de-velopment money. If sample return is to be accom-plished, significant investment in cryogenic sampling, return, and curation technologies is needed. References:  Vision & Voyages for Planetary Sci-ence in the Decade 2013-2022 (2013) 399 pp.  Sanin et al. (2017) Icarus 283, 20-30.  Paige et al. (2010) Science 330, 479-482.  Smith et al. (2017) Icarus 283, 70-91.