Lunar A & B

NASA

NASA Kennedy Space Center Director Bob Cabana, left, Special Assistant to the Director Robert Hubbard, center, and NASA Deputy Administrator Lori Garver scan the sky for the space shuttle Discovery as it approaches for landing at the Kennedy Space Center in Cape Canaveral, Fla., Tuesday, April 20, 2010. Discovery and the STS-131 mission crew, Commander Alan G. Poindexter, Pilot James P. Dutton Jr. and Mission Specialists Dorothy Metcalf-Lindenburger, Rick Mastracchio, Stephanie Wilson, Clayton Anderson and Japanese astronaut Naoko Yamazaki returned from their mission to the International Space Station.Photo credit: (NASA/Bill Ingalls)

Astronaut James Irwin gives salute beside U.S. flag