Feb 17, 2012 -- Mercury astronauts John Glenn, left, and Scott Carpenter sit in front of the plot board from the Mercury control center on display at the Kennedy Space Center Visitor Complex. The astronauts, part of the original class of seven astronauts chosen by NASA, were taking part in a question-and-answer session with the media as part of events celebrating 50 years of Americans in orbit, an era which began with John Glenn's Mercury mission MA-6, on Feb. 20, 1962. Glenn's launch aboard an Atlas rocket took with it the hopes of an entire nation and ushered in a new era of space travel that eventually led to Americans walking on the moon by the end of the 1960s. Glenn soon was followed into orbit by Carpenter, Walter Schirra and Gordon Cooper. Their fellow Mercury astronauts Alan Shepard and Virgil "Gus" Grissom flew earlier suborbital flights. Deke Slayton was grounded by a medical condition until the Apollo-Soyuz Test Project in 1975. Photo credit: NASA/Kim Shiflett