CRISM Compact Reconnaissance Imaging Spectrometer for Mars on MRO

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CRISM (Compact Reconnaissance Imaging
Spectrometer for Mars) on MRO
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Outline

• Team
• Investigation strategy
• Instrument overview
• Instrument performance
• Data and data products

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CRISM Team
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OMEGA and CRISM A 2-stage VISIR spectral
investigation of Mars

• OMEGA is revealing unexpected diversity
• Variations in px composition, new ol-rich areas
• Concentrations of hydrated minerals (sulfates,
  clays)
• Mapping / grain size determination of CO2 and H2O
  components of polar caps
• However...
• Spatial resolution is 1 km
• Observations nearly all nadir, so surface /
  atmosphere separation model-dependent
• CRISM will build on OMEGA with
• gt20x greater spatial resolution
• 2x greater spectral resolution
• Extensive measurements to separate the surface
  and atmosphere

Variations mafic mineralogy of Syrtis Major Region
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CRISM Objective 1 Find deposits of interest up
to 5 times smaller
Proof of concept using resampled AVIRIS data
OMEGA (300-1000 m/pixel,13 nm/ch.) discovers
large deposits
CRISM multispectral survey (100- 200 m/pix, 72
ch.) discovers small deposits
CRISM targeted hyperspectral (15-38
m/pixel, 6.55 nm/ch) characterizes deposits

• OMEGA is discovering deposits of interest
  kilometers in size
• CRISMs multispectral survey will discover
  deposits to 200 m size
• CRISM will characterize these targets
  hyperspectrally at 15-38 m/pixel

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CRISM Objective 2 Separate the Surface and
Atmosphere

• Time- and spatially-variable aerosols strongly
  affect the signature of the surface and
  complicate mineralogic interpretations

• The surface and atmosphere can be separated by
  viewing the same surface at different geometries,
  using "emission phase functions (EPFs)"

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Emission Phase Functions Provide Valuable
Information on Atmospheric Variability

• CRISM will measure emission phase function (EPFs)
  with each targeted observation
• Overlapping footprints provide 11 emission angles
  for central high-res swath

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Emission Phase Functions Provide Valuable
Information on Atmospheric Variability
BD1400H2O H2O Vapor

• Global grids of EPFs will be acquired to measure
  seasonal variations in aerosols and trace gases

Proof of concept using OMEGA data
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CRISM Objective 3 Measure sites of interest in
unprecedented detail
CRISM will provide hyperspectral maps at very
high spatial / spectral resolution to
characterize the geology of key sites
Endurance Crater at MER/Opportunity site
(squaresCRISM pixels)
Spectra of analog materials in CRISM wavelength
range
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Investigation Overview
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CRISM Subsystems and Functions

• Data Processing Unit (DPU)
• Power
• Control of exposure times, frame rate
• Data editing, binning, compression

• Optical Sensor Unit (OSU)
• Telescope and baffling
• Dual VNIR and IR spectrometers
• Actively cooled IR focal plane
• Passively cooled instrument housing
• Shutter for interleaved background calibrations
• Closed-loop, brightness-controlled internal
  integrating sphere for calibrations
• Focal plane electronics
• Gimbaled to 60
• Gimbal Motor Electronics (GME)
• Controls gimbal motion

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Key Aspects of System Performance
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Data Reconstruction (Breccia during ground
calibration)
1 frame
Cube sliced to produce spatial image
Gimbal scan forms a cube of spatial-spectral
image frames
Water
Extracted spectrum shows alteration products as
sought on Mars
Clay
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CRISM Data Products / Key Results

• DATA ACQUIRED
• 3000-6000 targeted hyperspectral images at 15-38
  m/pixel, 545 wavelengths
• Global map in 72 colors, 200 m/pixel
• 3000-10,000 72-channel "windows" at 100 m/pixel
• Up to 36 global grids of emission phase functions
  (5000 observations)
• ANALYSIS RESULTS
• Global distribution of major rock types
• High-resolution mineralogic maps of key sites
• Seasonal variations in atmosphere
• Identification / characterization of landing
  sites for Mars Phoenix and MSL

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CRISM Data Products / Key Results

• DATA ACQUIRED
• Spectral parameters and mineral indicators (33
  surface, 11 atmosphere)Pelkey et al., 2006 (in
  prep)

Test of parameters with OMEGA data R Olivine G
LCP B HCP
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CRISM Data Products / Key Results

• DATA ACQUIRED
• Spectral parameters and mineral indicators (33
  surface, 11 atmosphere)Pelkey et al., 2006 (in
  prep)

Test of parameters with OMEGA data R Olivine G
LCP B HCP
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CRISM Data Products / Key Results

• DATA ACQUIRED
• Spectral parameters and mineral indicators (33
  surface, 11 atmosphere)Pelkey et al., 2006 (in
  prep)

Test of parameters with OMEGA data R 1.9 µm G
2.4 µm B 2.3 µm
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Basic Data Products Raw Data

• About 27,000 distinct observations
• About 320,000 commanded image sequences
• Each produces a raw data cube like this
• Every 3 months after 6 months of validation

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Basic Data Products Calibrated Targeted
Observations

• 3000-6000 targeted hyperspectral images 5000
  EPFs
• Each, once calibrated, yields 11 multi-band
  images like this
• Every 3 months after 6 months of validation

Standard product
Special product
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Multispectral Map Tiles

• 2500 multispectral "noodles" mosaicked to create
  global map
• 72 colors, 200 m/pixel
• Tiles produced on best-effort basis every 6 mo.
  after 6 mo. validation
• 1964 5x5 tiles

Standard product
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Spectral Library to Support Data Analysis

• Searchable database of 1500 spectra of analog
  materials
• CRISM spectral range, measured under Mars-like
  desiccation
• Released at Mars orbit insertion