Friendship 1

John Glenn actually named his spacecraft Friendship 7. The Mercury astronauts were given the privilege of naming their own spacecraft, in the USAF tradition. Alan Shepard chose Freedom 7; according to NASA, this was "because it was the seventh one made." The subsequent astronauts in the programme also used the figure 7; NASA says this was "in honor of the seven astronauts chosen for the project [Mercury]."

Details:

Mission	Call–sign	Pilot	Launch date	Duration (hh:mm:ss)	Orbits
MR–3	Freedom 7	Alan Shepard	5 May 1961	00:15:22	0
MR–4	Liberty Bell 7	Virgil 'Gus' Grissom	21 July 1961	00:15:37	0
MR–6	Friendship 7	John Glenn	20 February 1962	04:55:23	3
MR–7	Aurora 7	Scott Carpenter	24 May 1962	04:56:05	3
MR–8	Sigma 7	Walter 'Wally' Shirra	3 October 1962	09:13:15	6
MR–9	Faith 7	Gordon Cooper	15 May 1963	34:19:49	22

The seventh Mercury astronaut was Donald 'Deke' Slayton, who was selected to pilot the second manned mission, but was grounded due to an irregular heart rhythm (atrial fibrillation). He eventually went into space in 1975 as one of three NASA astronauts in the Apollo–Soyuz Test Project (ASTP) – the first joint US–Soviet mission, in which an unnumbered Apollo command and service module (left over from the cancelled Apollo missions) docked with a Soviet capsule named Soyuz 19.