After more than 130 missions over nearly 30 years, NASA's space shuttle program is gearing up for its final flight, when Endeavour will deliver the Alpha Magnetic Spectrometer, a $1.5 billion particle detector, to the International Space Station.
"It is obviously time for these vehicles to be given an honorable retirement, and I do emphasize honorable," said Roger Launius, senior curator of human spaceflight at the Smithsonian National Air and Space Museum. "They have served well, but they are obsolete and it's time to move on."