A US project 1961–3 to put a human in space using the one-seat Mercury spacecraft.

The first two Mercury flights, on Redstone rockets, were short suborbital voyages to the edge of space and back. The flights were known by the double name of Mercury–Redstone, with Alan Shepard flying on Mercury–Redstone 3 to become the first US astronaut in space on 5 May 1961. The orbital flights were launched by Atlas rockets. The Mercury–Atlas 6 flight was made on 20 February 1962 by John Glenn, who became the first US astronaut to orbit the Earth.