ExoMars camera to give stereo view
The camera system on Europe's ExoMars orbiter will acquire stereo imagery of the planet's surface - at a best resolution of 4.5m per pixel - to help track down possible sources of methane.
Nic Thomas from the University of Bern, Switzerland, is the instrument's principal investigator.
He told our correspondent Jonathan Amos how CaSSIS, as it is known, will work.