Today On Mars: MAHLI Translates Martian Discoveries For Human Eyes

To get an idea of the color or size of an object on Mars, it helps to have a point of reference.

The MAHLI Calibration Target

Two images were combined to take this photo of the calibration target for the Mars Hand Lens Imager (MAHLI). That penny at the bottom? It's a sly nod to geologists' practice of putting coins in photos for size reference.NASA/JPL-Caltech/Malin Space Science Systems

Mars rover Curiosity has plenty of tools to help it see and explore, but we need some assistance to understand what those discoveries would look like back on Earth. The rover took this snapshot on a recent "sol" (Mars day) of the tool that helps make that possible: the MAHLI calibration target.

It's two combined photos, actually, taken by Curiosity's Mars Hand Lens Imager, a handy camera used for close-up inspections. The calibration target is on the end of Curiosity's robotic arm, and this was taken as part of a week-long test of the arm's mobility. On the target, you can see a penny (for size reference), color chips (color reference, of course), a metric standardized bar graphic (size), and a stair-step pattern (depth).

The penny is unique (even by non-Mars-roving-penny standards): it's from 1909, the first year Lincoln pennies were minted and the centennial of Lincoln's birth.