NASA Administrator Charles Bolden (left) and John Glenn (right) participate in the NASA Tweetup during the "Celebrating John Glenn's Legacy: 50 Years of Americans in Orbit 1962 - 2012" event at Cleveland State University on March 2, 2012.   Mike Lynaugh

NASA Administrator Charles Bolden (left) and John Glenn (right) participate in the NASA Tweetup during the "Celebrating John Glenn's Legacy: 50 Years of Americans in Orbit 1962 - 2012" event at Cleveland State University on March 2, 2012.

Mike Lynaugh