IEEE - Aerospace and Electronic Systems - March 2020 - 46

Feature Article:

DOI. No. 10.1109/MAES.2019.2950746

Lunar Flashlight: Illuminating the Lunar South Pole
Barbara A. Cohen, NASA Goddard Space Flight Center
Paul O. Hayne, University of Colorado
Benjamin Greenhagen, JHU Applied Physics Laboratory
David A. Paige, University of California, Los Angeles
Calina Seybold, John Baker, Jet Propulsion Laboratory

INTRODUCTION
Water ice and other volatile compounds may be present on
the Moon's surface within permanently shadowed regions
(PSRs) near the lunar poles. Understanding the composition, quantity, distribution, and form of water and other
volatiles associated with lunar PSRs is identified as a Strategic Knowledge Gap (SKG) for NASA's human exploration program, projected to visit the lunar south pole in the
next decade. These polar volatile deposits are also scientifically interesting, having potential to reveal important
information about the delivery of water to the Earth-Moon
system.
Lunar Flashlight is a very small satellite (6U bus, or
12 Â 24 Â 36 cm), developed and managed by the Jet
Propulsion Laboratory, that will search for water ice
exposures and map their locations in the Moon's south
polar region. The Lunar Flashlight mission will demonstrate technologies for NASA such as green propulsion
and active laser spectroscopy while proving the capability of performing a planetary science investigation in the
CubeSat form factor. Lunar Flashlight was selected in
2014 by the NASA Advanced Exploration Systems

Authors' current addresses: Barbara A. Cohen, NASA
Goddard Space Flight Center, Greenbelt, MD 20771 USA
(e-mail: Barbara.A.Cohen@nasa.gov); Paul O. Hayne,
University of Colorado, Boulder, CO 80309 USA (e-mail:
Paul.Hayne@lasp.colorado.edu); Benjamin Greenhagen,
JHU Applied Physics Laboratory, Laurel, MD 20723
USA (e-mail: benjamin.greenhagen@jhuapl.edu); David
A. Paige, University of California, Los Angeles, CA
90095 USA (e-mail: dap@mars.ucla.edu); Calina Seybold,
Jet Propulsion Laboratory, Pasadena, CA 91109 USA
(e-mail: calina.c.seybold@jpl.nasa.gov); John Baker,
Jet Propulsion Laboratory, Pasadena, CA 91109 USA
(e-mail: john.d.baker@jpl.nasa.gov).
Manuscript received April 5, 2019, revised July 16, 2019,
and ready for publication October 29, 2019.
Review handled by F. Davarian.
0885-8985/19/$26.00 ß 2019 IEEE
46

program within the Human Exploration and Operations
Mission Directorate; the mission is currently funded as a
technology demonstration mission within NASA's Space
Technology Mission Directorate (STMD) portfolio.
Lunar Flashlight will be one of 13 secondary payloads
launched on Artemis-1, currently scheduled for 2020.

SCIENCE AND PAYLOAD
Water on the Moon contains both a record of science and a
resource for exploration. Volatile compounds are fundamental tracers of a planetary body's origin, evolution, and
interaction with its space environment. The observed
abundance and chemical inventory of condensed volatiles
may also reveal a history of dynamical exchange among
different regions of the solar system. Near the poles of the
Moon, large areas of perennial (or "permanent") shadow
create cold traps, where volatiles would be thermally stable for billions of years. PSRs may, therefore, hold a
record of volatile delivery, transport, sequestration, and
loss through geologic time [1], [2]. In addition, water
could be an important target of in situ resource utilization
(ISRU), where O2 and H2O for life support or H2 and O2
for fuel and propellant could be derived from deposits of
water ice [3]-[5].
Lunar polar water ice consists of at least two reservoirs: deeply buried ice deposits and surficial water frost.
The Clementine, Lunar Prospector, and Lunar Reconnaissance Orbiter (LRO) missions made observations consistent with ice deposits centimeters-to-meters deep in PSRs
with concentrations $1% H2O by mass [6]-[9], but not all
PSRs contain water ice signatures. The Lunar CRater
Observation and Sensing Satellite (LCROSS) mission
excavated and heated 10's of m of regolith, revealing 5-7
wt% of H2O along with a comet-like array of volatiles
[10]. At the lunar surface, spectroscopic and albedo measurements from LRO and the Chandrayaan-1 Moon Mineralogy Mapper (M3) show increased surface reflectance
consistent with water frost at concentrations ranging from

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