Today Mars makes its closest approach to Earth, coming to within 62 million kilometers and outshining everything in the sky except for the sun, moon, and Venus. It won't be this close again until 2035. The Curiosity rover, which landed on Mars in 2012, has several cameras with varying resolutions and fields of view. There's a resolution test target mounted on the exterior of the rover that's used to calibrate these cameras. One of the test targets is a 1909 VDB Lincoln cent, so this is literally a penny that's out of this world. Here's what the test target looks like (photo taken before launch). And here it is on Mars:
