Ice At the Moon - How the Moon Mineralogy Mapper on

Chandrayaan-1 Will Help

Noah E. PetroNASA Goddard Space Flight

CenterMarch 4th, 2009

A Bit About Me

• Grew up in southern New York state• Became interested in Geology as a

student at the Fox Lane High School• Earned a degree in geology and

education from Bates College (2001)• PhD from Brown University in 2006• Post Doctoral researcher at NASA

Goddard

Clementine Albedo

Topography

Color

Lunar ProspectorFeO

Th

PolarH

The Moon’s Orientation

1.54º tilt to the ecliptic

Kaguya View of Shackleton/South Pole

Earth Based Radar View of the South Pole

Lunar South Pole

The search for water …

Ice on the Moon

Lunar Prospector Neutron Spectrometer looks for "slow" (or thermal) and "intermediate" (or epithermal) neutrons which result from collisions of normal "fast" neutrons with hydrogen atoms. The ice was thought to be spread over 10,000 to 50,000 square km and amount to 6 billion metric tons. A significant amount of hydrogen would indicate the existence of water - 4.6% over the north polar region and 3% over the south, at a depth of about 40 centimeters beneath dry regolith.

1) Fluxes of fast and epithermal neutrons from Lunar Prospector: Evidence for water ice at the lunar poles, Feldman et al., Science, v. 281, p. 1496, 1998

Moon’s inclination to the Sun is only 1.5°, allowing permanently shadowed regions inside craters

No water (as OH-) was detected from the July 31, 1999 crash of Lunar Prospector into the Moon.Possible reasons: might have missed the target area; might have hit a rock; crash had too little energy to separate water from minerals; plume hidden from telescopes by crater walls; telescopes mispointed; or hydrogen simply may not be in the form of water ice.

Lunar South Pole

The search for water …

Lunar Prospector data

Map of Hydrogen(red = greater abundance of H)

Lunar South Pole

The search for water …

View into Shackleton Crater

View into Shackleton Crater

Polar cold traps• Scientists use the Kelvin absolute

temperature scale, where ice melts at 273.16 K.

• Dry ice forms at Mars atmospheric pressure at 145 K, water ice clouds form at ~180-200 K.

• Liquid oxygen (1 bar): 90 K

• Liquid nitrogen (1 bar): 77 K

• Temperatures in Shackleton Crater: 88-86 K

No surface ices

exposed?

Mission Overview:M3 on Chandrayaan-

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What We Know From Apollo

What We Learned

• Lunar samples are all very dry

• Limited compositional variability relative to the Earth

• Small amount of water in volcanic glasses

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Lunar Samples

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Water

Olivine

Pyroxenes

Plagioclase

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The Electromagnetic Spectrum &Lunar Mineral

Signatures

M3 Pushbroom Imaging Spectometer

40 km Swath62.3 m Sampling

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Orbit PathContinuous

M3 Pushbroom Imaging Spectometer

40 km Swath62.3 m Sampling

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M3 as a mapping spectrometer

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View into Shackleton Crater

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Lunar Samples

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Water

Olivine

Pyroxenes

Plagioclase

Glass

Lunar Mineral Signatures

Lunar Reconnaissance Orbiter / Chandrayaan-1

• Two most recent (late 2008-2009) spacecraft orbiting Moon

• Powerful, modern radar experiments will image PSR’s in detail

• Lyman-Alpha Mapping Project (LAMP) will see interiors of PSRs by galactic far-ultraviolet light (hydrogen emissions)

• Lunar Orbiter Laser Altimeter will measure albedo on 5-m footprint scales, detecting 4% ice

• Neutron spectrometer (LEND) will resolve hydrogen atoms

• DIVINER will measure surface temperatures and rock environments

Lunar CRater Observation and Sensing Satellite [LCROSS]

For more information…

• Lunar Photo of the Day– http://lpod.wikispaces.com/

• Lunar and Planetary Institute -Lunar Resources– http://www.lpi.usra.edu/lunar/

• Apollo Surface Journal– http://history.nasa.gov/alsj/