This artist's rendition depicts a concept for a Mars orbiter that would
scrutinize the martian atmosphere for chemical traces of life or
environments supportive of life that might be present anywhere on the
planet. The illustration is presented as a three-dimensional stereo view.
The concept is named the Mars Volcanic Emission and Life Scout, or
Marvel. It would equip a Mars orbiter with two types of instruments
proven useful in studying Earth's atmosphere from Earth orbit. One, a
solar occultation infrared spectrometer, would look sideways through
Mars' atmosphere toward the setting or rising Sun for an extremely
sensitive reading of what chemicals are in the air that sunlight passes
through before hitting the instrument. The other, a submillimeter
spectrometer would survey the atmosphere continuously, including during
dust storms and polar night, to seek localized surface sources of the
chemicals of interest. The infrared spectrometer has very high
sensitivity for one chemical of great interest: methane, which is
produced by many types of microbes, as well as by some volcanic sources.
The submillimeter spectrometer has very high sensitivity for water vapor.
Localized concentrations of water vapor in the atmosphere could identify
places where subsurface water sources may be venting.
