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.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.