Visible-light imagersVisible-light imagers have been the most common remote sensor sent to Mars since Mariner 4Mariner 4 captured the first images of the planet near the start of the space age. The first successful lander, Mars 3, used a cyclotronic imager to attempt to return the first image from the surface; with every successful surface mission carrying cameras in the decades since (Chap.  1 ). On-orbit and surface-based visible light imaging technology remains a predominant tool for past and present surface process interpretation and change monitoring (Barlow in Mars: an introduction to its interior, surface and atmosphere. Cambridge University Press, New York, 2008). This type of imagery is also critical for engineering functions, such as safe landing site selection (Golombek et al. in Space Sci Rev 170:641–737, 2012), as well as identifying safe navigation paths for moving vehicles to follow (e.g. Rankin et al. in J Field Robot 38:759–800, 2021).