Mercury-Atlas launch. Launch of the small Mercury spacecraft (black), only large enough for one crew member, on top of the Atlas rocket. Project Mercury was the first human spaceflight programme of the United States. It ran from 1959 to 1963, succeeding in putting the first US astronaut in space on 5 May 1961. A total of six missions were flown, with four using the 29-metre long Atlas rocket. Mercury flights were launched from Cape Canaveral Air Force Station in Florida, USA.