CRISM General Intro - cpshooter/geoML GitHub Wiki

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter is the most recent spectrometer to arrive at Mars. The instrument is a hyperspectral imager covering visible to near-infrared wavelengths (0.37 – 3.92 mm at 6.55 nm/ channel) and has two modes of operation [Murchie et al., 2007]. The survey mode will achieve global coverage of the planet at
200 m/pixel in 72 selected channels. The targeted mode will acquire thousands of observations covering <1% of the surface at
20 m/pixel in 545 channels, an unprecedented spatial resolution for hyperspectral data. As a means for rapid assessment of the vast amounts of data that CRISM will return, the team has defined summary products based on spectral parameters derived from the 72 channels that will be acquired in both survey mode and targeted observations [Murchie et al., 2007]. The intention is to use the summary products derived from the survey mode data to characterize composition at the global scale and to search for areas of mineralogic interest to observe in the targeted mode, and to use the summary products derived from the targeted observations as tools for initial assessment in analysis.

Targeted (hyperspectral) ~ 6500 per Mars year

• Full resolution (FRT) Spatial pixels unbinned for target - 18 m/pixel @300 km, 10x binned for EPF
• Half resolution short (HRS) Spatial pixels 2x binned for target - 36 m/pixel @300 km, 10x binned for EPF; same swath length as above
• Half resolution long (HRL) Spatial pixels 2x binned for target - 36 m/pixel @300 km, 10x binned for EPF; twice swath length as above

The hyperspectral survey is an augmentation of the multispectral survey, with the increased density of wavelength sampling providing capability to separate subtly different spectral signatures and to provide improved capability to detect and map carbonate absorptions. It is intended to map regions rich in mineral diversity where contiguous coverage by targeted observations is impractical over the lifetime of MRO. As with multispectral survey, the basic configuration is a repeating sequence of alternating Mars-viewing and background measurement macros. The data are always taken in 12-bit format. Scene data and accompanying background calibrations are taken in 10x pixel binning mode at 15 Hz frame rate, yielding 200-m effective pixels.