The Mercury-Redstone 3, MR-3 or Freedom 7 spaceflight was the firsthuman spaceflight by the USA and took place on 5 May 1961, with Alan Shepard as the astronaut. It was part of Project Mercury which was an attempt by the USA to bring an astronaut into orbit around the Earth before the Soviet Union during the Cold war. This first manned mission, however, was only a 15-minute suborbital flight meaning above the limit of space at an altitude of 100 km (62 mi) and down again. The last part of the mission name came from the Redstone rocket that was used for launching the spacecraft. It was the fourth mission by that rocket in the project; the former being unmanned test flights of which one carried achimpanzee. The launch of MR-3 took place at Cape Canaveral, Florida close to the Atlantic Ocean. After the rocket had burned out, the spacecraft with Shepard on board separated from it and continued until it reached an altitude of 116.5 miles (187.5 km) before falling back and landing by parachute on the ocean off the Bahamas. Here it was picked up by helicopter and brought to an aircraft carrier. During the flight, Shepard observed the Earth and tested the reaction control system of the spacecraft together with a pack of small rockets meant for bringing a spacecraft down from orbit on later missions. It was also Shepard who had given the mission its alternative name, "Freedom 7," setting a trend of astronauts naming their spacecraft for the rest of the project.

The mission was a technical success even though it failed to bring the first man into space; just 3 weeks before, the Soviet Union had carried out theirfirst orbital flight. MR-3 was followed by another suborbital mission the same year and four orbital missions the following two.