Former U.S. Senator and Astronaut John Glenn greets audience members during the transfer ceremony for Shuttle Discovery at the Smithsonian's National Air and Space Museum's Udvar-Hazy Center in Chantilly, Virginia on April 19, 2012. The Space Shuttle Discovery is replacing the Space Shuttle Enterprise, which will be transporter to the Intrepid Sea, Air and Space Museum in New York City. UPI/Kevin Dietsch