President Barack Obama is about to leave office, but his imprint will forever reside on Mars.
On Thursday, NASA's Curiosity Mars rover's Twitter account sent out a photo of a plaque bearing the signatures of President Obama, Vice President Joe Biden, and other US officials. The rectangular aluminum plaque is affixed to the rover's deck, and also bears NASA's logo.
The photo was taken back on September 19, 2012, the rover's 44th Martian day, by the Mars Hand Lens Imager.
The president tweeted his reaction to the plaque, and got in a spacey joke in the process.