ASTRONAUT EDGAR MITCHELL - NASA

(CNN) Edgar Mitchell, one of just 12 human beings who walked on the moon, has died, according to his ex-wife, Anita Mitchell. Mitchell was 85.

"On behalf of the entire NASA family, I would like to express my condolences to the family and friends of NASA astronaut Edgar Mitchell," NASA Administrator Charles Bolden said in a statement.

"He believed in exploration, having been drawn to NASA by President Kennedy's call to send humans to the moon. He is one of the pioneers in space exploration on whose shoulders we now stand."

Edgar Mitchell in his official Apollo 14 portrait.

Mitchell died Thursday in West Palm Beach, Florida, according to NASA. His death occurred on the eve of the 45th anniversary of his lunar landing, which took place on February 5, 1971.

Mitchell, Alan Shepard and Stuart Roosa were the crew of Apollo 14, which launched on January 31, 1971. Mitchell became the sixth man to walk on the lunar surface.

He and Shepard set foot on the moon two separate times during their mission, spending more than nine hours collecting rocks, taking measurements and (in Shepard's case) hitting a pair of golf balls. Mitchell also took a famous photograph of Shepard standing next to an American flag. All told, the two spent 33 hours on the moon.