Cernan became the answer to a trivia question when he was the last human to leave his footprints on the lunar surface as part of the Apollo 17 crew in 1972.

After a career as a Marine pilot, Glenn was chosen as an astronaut. He was the third American in space, went on to have a successful career in politics and then returned to space on shuttle Discovery.

Terre Haute native Abe Silverstein was inducted Friday into the Dayton, Ohio-based hall of fame.

The latest photos show ice plains that appear to be only 100 million years old and a hilly region that could be what is left when surrounding material is eroded away.