The original seven Project Mercury astronauts: front row, from left, are Walter M. Schirra, Jr., Donald "Deke" K. Slayton, John Glenn Jr., and M. Scott Carpenter. Back row, from left, are Alan Shepard Jr., Virgil I. "Gus" Grissom, and Gordon Cooper. After the death of Carpenter, John Glenn is now the only surviving member of the original Project Mercury astronauts.
Source: http://news.discovery.com/space/history-of-space/the-right-suff-scott-carpenters-mission-photos-131011.htm
