principle investigator payload manager
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Anthony Colaprete. Principle Investigator Payload Manager. LCROSS Background. Lunar Prospector detected an increase in hydrogen concentration over the lunar poles. The debate over the form, concentration and distribution has continued ever since. - PowerPoint PPT PresentationTRANSCRIPT
Lunar CRater Observation and Sensing Satellite Project
LCROSS
Principle Investigator Payload Manager
Anthony Colaprete
2LCROSS Background
Lunar Prospector detected an increase in hydrogen concentration over the lunar poles.
The debate over the form, concentration and distribution has continued ever since.
If the hydrogen in an accessible and usable form, it could be a potential resource?
The form, distribution and concentration of [H] relevant to inner solar system asteroid/comet fluxes, lunar volatiles and planetary evolution.
Feldman et al., 1998
SP Hydrogen Abundance
LCROSS will provide the most unambiguous data set to date as to the nature of lunar hydrogen2
3 3Question Addressed by LCROSS
Nature and form of the hydrogen?• Water, hydrated minerals, hydrocarbons?• Grain size?• Distribution within regolith?
Nature of PSR regolith?• Strength? Depth?• Grain size?• Composition?• Is it similar to Apollo sites?
The Lunar Atmosphere / Volatile Processes?• How does the Lunar atmosphere respond?• What are the times scales for recovery?• How do volatiles/dust migrate?
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Deconvolved Hydrogen Maps (Elphic et al., 2007)
Lunar Polar Hydrogen: What we do know
Original Lunar Prospector Hydrogen Map (Maurice et la., 2003)
Water is heterogeneous from one crater to another Accumulation/retention processes differ at carter scales of ~50-100 km? Possibly different at smaller scales.
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Evenly Distributed, low concentrations“Smooth”
Higher, infrequent concentrations “Chunky”
The LCROSS Experiment: Smooth or Chunky?
Processes such as impacts, diffusion, topography and sputtering may effect the distribution.
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Launch stacked with LRO May 21, 2009
After Lunar swing-by, enter a 3.5 month cruise around Earth
August 28, 2009, target the Centaur Upper Stage and position S-S/C to fly four minutes behind
S-S/C observes impact, ejecta cloud and resulting crater, making measurements until impacting itself
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The LCROSS Mission
MoonEarth
LCROSS Orbit – Side View
MoonEarth
LCROSS Orbit – Side View
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East Crater ~30 meters
Predicted Centaur Crater Size
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Korycansky et al., 2008) Schultz et al., 2008)
SPH Modeling NASA AVRG Experiments
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0
50
100
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0 20 40 60 80
Impact Angle (degrees)
Eje
cta
Ma
ss
(M
etr
ic T
on
es
)
LCROSSSMART-1LPLCROSS S-S/C
SMART-1 (grazing impact) LP
Estimates of the total ejecta mass as a function of impact angle for four impactors: LCROSS, LCROSS S-S/C, Lunar Prospector (LP), and SMART-1
LCROSS
LCROSS S-S/C
SMART-1 (hill side impact)
The Impact – How Does it Compare?
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9The LCROSS Spacecraft
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10The LCROSS Payload
NIR SpectrometerUV/Visible Spectrometer
Visible Color
Camera
MIR Cameras
NIR Cameras Flash Radiometer
Solar NIR Spec
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Visible
NIR 2 NIR 1
MIR 1 MIR 2
Yours Truly…in Five Wavelengths
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VSP
NSP
NIR1VSP NIR2
LCROSS Wavelength Coverage
MIR1: 7-9 mMIR2: 7-12 m
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Impact @ 06:30 UTCHawaii lunar elevation = 39.9 deg @ impact
Ground Based Observations
Observatories Planning Observations:HSTOdin (EU)CFHTApache PointIRTFMMT (Az)UKIRTMROKeckGemini NorthSubaruASSI (Korea)
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Impact Expectations: Earth Brightness (per 1 sqr arc sec)
Curtain Area Average Brightness
15Summary
We’ll know in about 5 months!
•Earliest likely impact date August 28, 2009 (for an May 21 launch)
•Should be visible from Earth in the Pacific (including west coast)
• Impact target selection an on-going process, currently headed north
•LCROSS SC and Instrument development demonstrated a novel approach: High scientific return per dollar spent
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Backup Slides
17Expectations: LCROSS Water Detection
-0.01
0.04
0.09
0.14
0.19
0.24
0
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1.35 1.55 1.75 1.95 2.15 2.35
% A
bs
orp
tio
n
Ra
dia
nc
e (W
m-2
m
-1s
tr-1
)
Wavelength (microns)
IrradianceAbsorption11 bin average
Calculated ejecta cloud radiance (left axis) and synthetic NIR spectrometer data for 1% water content
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The radiance for the ejecta cloud only (derived be subtracting off the spectra from the lunar surface) for several times after Centaur impact.
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0.5
1
1.5
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0 0.5 1 1.5 2 2.5 3 3.5
Wavelength (microns)
Ra
dia
nc
e (
W m
-2 m
icro
n-1
str
-1)
t=10
t=20
t=30
t=40
t=60
t=70
t=80
t=90
t=100
Expectations: Curtain Brightness
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19The LCROSS Experiment: Smooth or Chunky?
Aerial fraction for 10 m craters that is in equilibrium, i.e., “wet”, is:
~1 – Crater Diameter2/Crater Spacing2 = 1.-102/1002 = 99%
Top meter sensed by LP is near the derived value: high concentration pockets (water greater than few %) in the top meter not likely….the Smooth model is predicted.
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