Project Mercury was first organized in October 1958. McDonnell was selected as the contractor for the Mercury capsules. The Redstone rockets used for the suborbital flights was a product of North American Rockwell, while the Atlas D was chosen for the orbital flights and was produced by Convair. The first seven astronauts had been selected by April of 1959.
Some Early Mercury Flights:
MA-1 - 29 July 1960. Intended suborbital flight lasted 3 minutes, 18 seconds. The Atlas booster suffered structural failure. Some fragments were recovered and are at the Kansas Cosmosphere and Space Center in Hutchinson, KS.
MR-1 - 21 November 1960. Reached an altitude of 4 inches, then settled back on the pad. Electrical malfunction.
MR-1A - 19 December 1960. Successful 15 minute, 45 second suborbital flight. This capsule is currently at the NASA Ames Exploration Center near San Jose, CA.
MA-2 - 21 February 1961. Suborbital flight lasting 17 minutes, 56 seconds. Craft is currently at the Houston Museum of Natural Science, Houston, TX.
MA-3 - 25 April 1961. Suborbital flight lasting 7 minutes, 19 seconds. The capsule was reused for MA-4.
MA-4 - 13 September 1961. Single orbit flight lasting 1 hour, 49 minutes, 20 seconds. The capsule was dismantled for parts in 1976.
The Mercury Program cost was USD 300 million (1962, USD 1.67 billion in 2001).
Cancelled Mercury Flights
It was originally planned that all 7 of the original astronauts first fly suborbital missions. These flights were scrubbed since the Mercury-Redstone phase of the program was running behind schedule, the Mercury-Atlas phase was nearly ready, and the Soviets had already sent a man into orbit. John Glenn had been scheduled to fly on MR-5 in September of 1961, and Deke Slayton was scheduled for MR-6 in November of that year.
Another point of interest is that an additional boiler plate Mercury launch was flown after minor booster problems during the suborbital flight of Ham the Chimp. This delayed the MR-3 flight of Alan Shepard. Had his flight not been delayed, Shepard would have beaten Gargarin into space by 3 weeks.
The flight of Gordon Cooper in Mercury 9 was the last Mercury flight. Nearly all of the spacecraft's systems had failed by the end of the day and a half flight. Due to these problems, and the fact that the Gemini program was nearly ready, the Mercury 10 flight by Alan Shepard scheduled for October of 1964 was scrubbed. This was to have been a 3 day flight, and the capsule was to be called "Freedom 7 II".