Conducting Subsurface Surveys for Water Ice using Ground Penetrating Radar and a Neutron Spectrometer on the Lunar Electric Rover

LPI/Kring David A. Kring Lunar and Planetary Institute Never Stop ───

Exploring Lunar Exploration Analysis Group 11 October 2017

NASA

Art by Daniel D. Durda Art by Daniel D. Durda David A. Kring

Roadmap for Human Exploration

• Outlines a plan that extends human exploration beyond low- Earth orbit (LEO)

• Includes multiple destinations (the , asteroids, and eventually Mars)

• Develops a mission scenario with • Precursor lunar robotic explorers, a • Human-assisted lunar sample return mission, and • Human lunar sample return missions.

David A. Kring

EXPLORATION – IN PARALLEL WITH ORION & SLS VEHICLE DEVELOPMENT

Detail of illustration from the GER (2013) with small modifications. Because the human missions could involve NASA’s Orion vehicle and ESA’s service module, notional Exploration Mission numbers have been added. Deep Space Gateway

NASA

The components of ISECG Design Reference Mission (DRM) as outlined by Hufenbach et al. (IAC, 2015)

• NASA’s Orion crew vehicle, with ESA’s service module, transports crew to/from a Deep Space Gateway • The Gateway is in the vicinity of the Moon, such as a halo orbit about the Earth-Moon L2 point above the lunar farside The components of ISECG Design Reference Mission (DRM) (continued) • Two small pressurized rovers (SPRs) for crew to explore the lunar surface; e.g., the Lunar Electric Rover (LER) • A crew lander with an expendable descent stage and reusable ascent stage

NASA NASA

• Generation I vehicle built & field tested • Notional • Generation II vehicle is designed • No design for crew lander yet exists • Once the Gen II vehicle has been tested, vehicles for flight can be built Distribution of Landing Sites

Nearside: • Malapert Massif

South Polar Region: • South Pole ( Crater)

Farside: • Schrödinger Basin • Crater • South Pole- Basin Center

WAC mosaic with 100 m/px resolution Traverse Studies

LER traverse studies between landing sites and at each landing site have been conducted and reported in preliminary form:

Kamps et al. (LPSC 2017) Ende et al. (LPSC 2017) Orgel et al. (ELS 2017) Mazrouei et al. (ELS 2017)

WAC mosaic with 100 m/px resolution Traverse: Malapert Massif to Shackleton Crater

• Traverse limit: 933km Malapert • Efficient traverse: 208 km Massif • Science traverse: 911 km

Cabeus • Science: Crater • Volatiles in Cabeus Crater Crater • Impact melt in Drygalski and Shackleton Craters Crater

• Structure of complex craters

Ashbrook Crater

LOLA 100 m/px slope map over hillshade ADDRESSING SCIENCE & EXPLORATION OBJECTIVES EN ROUTE

Heggy & Kring installed a GPR in the frame of the LER.

An initial test was conducted at Moses Lake (2008), where the GPR successfully detected subsurface water.

The GPR was also deployed during a 14-day-long simulation at Point (2009) and remained functional throughout a traverse in challenging terrain.

GPR ADDRESSING SCIENCE & EXPLORATION OBJECTIVES EN ROUTE

• Exploration of lunar subsurface structure using GPR can investigate: • thickness and layer structure in lunar regolith • geological structure in the shallow lunar crust

• Chang’e-3’s Lunar Penetrating Radar aboard the Yutu rover illustrated the potential of a GPR, providing significant data on the subsurface

Fa et al. (2015) ADDRESSING SCIENCE & EXPLORATION OBJECTIVES EN ROUTE

• Exploration of lunar subsurface structure using GPR can investigate: • thickness and layer structure in lunar regolith • geological structure in the shallow lunar crust

• Thus, an LER tele-operated in survey mode may be able to detect and map the distribution of recoverable deposits of volatiles

Fa et al. (2015) ADDRESSING SCIENCE & EXPLORATION OBJECTIVES EN ROUTE

Neutron Spectrometer

To enhance the survey for subsurface volatiles, a neutron spectrometer, like the one Rick Elphic produced for the Resource Prospector rover (left), could be installed too.

For good signal-to-noise, LER speed would need to be ≤10 cm/s, but there is plenty of margin in the traverse schedule to allow that relatively slow speed. Traverse: Shackleton Crater to Schrödinger Basin

• Traverse limit: 938 km • Efficient traverse: 734 km Crater • Science traverse: 923 km Shackleton Crater • Science: • Volatile distribution and structures in complex crater in Amundsen Crater

• Geological contacts around the South Pole

• Stratigraphy in Schrödinger Basin wall

Schrödinger Basin

LOLA 100 m/px slope map over hillshade Traverse: Shackleton Crater to Schrödinger Basin

Amundsen Crater

Shackleton Crater

Schrödinger Basin

Within Amundsen Crater GPR & NS survey of volatiles en route Kamps et al. (LPSC 2017) Traverse: Shackleton Crater to Schrödinger Basin

Amundsen Crater

Shackleton Crater

Schrödinger Basin

Within Amundsen Crater GPR & NS survey of volatiles en route Kamps et al. (LPSC 2017) Traverse: Shackleton Crater to Schrödinger Basin

Amundsen Crater

Shackleton Crater

Schrödinger Basin

Within Amundsen Crater GPR & NS survey of volatiles en route Kamps et al. (LPSC 2017) Summary

• The LER component of the ISECG design reference mission is a mature concept

• A Generation I vehicle has been tested in the field in a series of 3-day, 14-day, and 28-day mission simulations

• Tests include >1152 hours of astronaut time in the vehicle and 2832 hours of total crew time in high- fidelity simulations.

• Traverse studies (Kamps et al., 2017; Orgel et al., 2017) indicate routes between the 5 sites in the ISECG DRM are feasible in this vehicle.

• Moreover, the tele-operated phases are excellent opportunities to survey for subsurface volatiles.