Finding Evidence of Mars’ Ancient Water

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is high-tech detective uncovering the compositional clues to the history of the Red Planet.

About the Instrument

Instrument Type

Where ancient water existed on Mars, what mineral record did it leave? How did it shape the surface, and could it have sustained life? How did Mars’ crust form? These are some of the questions that the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) was built to answer.

3D model of CRISM instrument
A detailed, 3D rendering of the CRISM instrument.

CRISM, flying on NASA’s Mars Reconnaissance Orbiter, has surveyed the Red Planet since 2005 in its search for mineralogic evidence of past water. CRISM’s observations, in part, confirmed the presence of large amounts of water on Mars in the past; they continue to reveal a complex geologic history and inform decisions on where to land rovers on the surface. Offering greater capability to map spectral variations than any similar instrument sent to another planet, CRISM can read 544 visible and near-infrared “colors” in reflected sunlight to distinguish different minerals in the surface and atmosphere. Scientists use these images to study Mars’ rock compositions, track changes in the planet’s atmosphere and examine how volatile ices move between the atmosphere and polar caps.