Transcript Ice Across the Solar System - Lunar and Planetary Institute

The Lunar Reconnaissance Orbiter
NASA’s Next First Step To The
Moon
Noah E. Petro
NASA Goddard Space Flight
Center
May 12th, 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
Lunar Prospector
FeO
Th
Color
Polar
H
The Moon’s Orientation
1.54º tilt to
the ecliptic
Kaguya View of
Shackleton/South Pole
Earth Based Radar View of the
South Pole
Resources on the Moon
Moon’s inclination to the Sun is only 1.5°, allowing permanently shadowed regions inside
craters
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
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)
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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?
Objectives of LRO
• Produce a high resolution “atlas” of the Moon
to be used to determine where we should/can
go with humans
•Study the lunar
surface to better
understand its
evolution
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What will LRO do?
• CRaTER - Radiation measurements of
lunar orbit.
• DIVINER (DLRE) - Will measure the
thermal environment of the surface.
• LAMP - Using UV light from stars, will
“look into” polar craters.
• LEND - Neutron detector to look for
Hydrogen
What will LRO do?
• LOLA - Laser altimeter to provide slope and
topography information
• LROC - Series of cameras
– NAC will provide high resolution views of surface,
with stereo capabilities
– WAC provides lower resolution regional views
• Mini-RF - Radar instrument to probe surface
for evidence of ice
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/
• LRO website
– http://lunar.gsfc.nasa.gov/index.html