The crew of space shuttle Discovery, from left, pilot James Dutton, mission specialist Dorothy Metcalf-Lindenburger, Japan Aerospace Exploration Agency astronaut Naoko Yamazaki, commander Alan Poindexter, mission specialists Rick Mastracchio, Stephanie Wilson and mission specialist Clayton Anderson, leave the Operations and Checkout Building on their way to board the shuttle at ...

Space shuttle Endeavour returns to the Kennedy Space Center in Cape Canaveral, Fla., Sunday, Feb. 21, 2010, after a 14-day mission to the International Space Station.(AP Photo/John Raoux) Copyright 2010  AP News

CAPE CANAVERAL, FL - FEBRUARY 08: Space Shuttle Endeavour lifts off from launch pad 39A at NASA's Kennedy Space Center February 8, 2010 in Cape Canaveral, Florida. The 13-day flight to the International Space Station is Endeavour's 24th mission, the 33rd shuttle flight dedicated to station assembly and one ...

CAPE CANAVERAL, FL - FEBRUARY 08: Space Shuttle Endeavour lifts off from launch pad 39A at NASA's Kennedy Space Center February 8, 2010 in Cape Canaveral, Florida. The 13-day flight to the International Space Station is Endeavour's 24th mission, the 33rd shuttle flight dedicated to station assembly and one ...