It's Rover's anniversary on Mars! Time to celebrate by throwing the best party this planet has ever seen. Rover hands out invitations all over town, but it seems like he's the only one around. Will come to the party, or will Rover be all alone on his big day? In 2013, NASA programmed their rover to hum "Happy Birthday to You" in honor of its first year on Mars. Inspired by this anecdote, this is the tale of a lonely rover and his party, accompanied by fascinating Mars rover facts that help explain the real science behind the story. This fun birthday tale provides an accessible, kid-friendly look at one of NASA's coolest programs.