I'm a hell of a lot cooler than you guys. Why don't you just fix your little problem and light this candle?

– Alan Shepard, May 5, 1961

On May 5, 1961, Alan Shepard became the first American to travel to space. His historic mission in the Freedom 7 spacecraft came a little over three weeks after the Soviet Union successfully made Yuri Gagarin the first person in space. While Gagarin’s spaceflight lasted 108 minutes and included a single orbit around Earth, Shepard’s lasted only 15 minutes and was suborbital.

Shepard’s mission was part of Project Mercury, NASA’s first human spaceflight program, and Shepard was part of a group of astronauts called the Mercury Seven.

Alan B. Shepard Jr earned his bachelor’s degree from the United States Naval Academy in 1944 and graduated from the Naval Test Pilot School in 1951 and the Naval War College in 1957. Shepard began his naval career deployed in the Pacific during World War II and he later entered flight training at Corpus Christi and Pensacola, earning his wings in 1947. As a pilot, Shepard logged more than 8,000 flying hours, 3,700 of which were in jet aircraft.

Shepard joined the astronaut program in 1959 and began training for his first spaceflight. According to NASA, the Mercury Seven’s training “was intended to provide the new astronauts with an education in astronautics and space biology, conditioning for space flight, training in the operation of the new Mercury vehicle, familiarization with ground operations, and aviation flight training.” This included time in the U.S. Navy’s centrifuge to test his ability to withstand severe acceleration and deceleration forces — while they couldn’t actually train in space, they could recreate the experience as best as possible. This made ground simulator training incredibly important and required that the selected astronauts be able to adapt quickly if the in-flight experience unfolded differently than in training.

After two years of training, the day was finally here: On May 5, 1961, Alan Shepard climbed into his Mercury spacecraft Freedom 7 and became the first American and second person in space on a 15-minute suborbital spaceflight.

To launch Shepard and his spacecraft into space, NASA turned to existing military ballistic missiles, modifying a U.S. Army Redstone rocket. The Mercury-Redstone Launch Vehicle was also used to launch Gus Grissom when he became the second American in space a few months later. From John Glenn’s 1962 orbital flight onward, Mercury missions were launched on modified U.S. Air Force Atlas ICBMs.

NASA turned to military designs once more for the Mercury spacesuits. Shepard wore a modified version of a U.S. Navy Mark IV flight suit (designed for high-altitude military pilots in the Navy and Marine Corps) for his Freedom 7 mission. Its futuristic look is thanks to a silver-colored coating meant to increase his visibility if an emergency rescue was needed. The zippers crossing the suit (27 in total!) were designed to make the fit very tight. In order for Shepard to get in and out of the suit, he had to unwrap that spiral zipper—practically going around his entire body—and then rewrap the suit around him, tightening the zipper as he went.

Shepard’s mission ended 15 minutes after launch with splashdown in the Atlantic Ocean. Throughout the mission, ground control had nearly continuous contact with Shepard through a worldwide network of ground stations, ships, and aircraft. NASA designed the Mercury capsule for a water landing, with a parachute that deployed at 24,500 feet to begin slowing the spacecraft. Unlike Yuri Gagarin, who parachuted out of his Vostok capsule, Shepard and other American astronauts stayed inside the capsule during the entire descent. After landing in the ocean, Shepard exited the spacecraft and was hoisted into a Navy helicopter and taken to the nearby aircraft carrier USS Lake Champlain.

Different than Gagarin’s secretive launch, Alan Shepard’s spaceflight was very highly publicized, and millions of people watched the launch live, turning him into a national hero. In the days after his successful spaceflight, Shepard received ticker-tape parades in DC, New York, and Los Angeles, and received the NASA Distinguished Service Medal from President John F. Kennedy. In 1963, Shepard became the Chief of the Astronaut Office after being grounded from future spaceflight due to a diagnosis of Ménière's disease, an inner-ear disorder that can cause dizziness and nausea. However, in 1969 Shepard underwent an operation to relieve the symptoms of Ménière's and was cleared to fly again. He returned to space as commander of the Apollo 14 mission in 1971, becoming the fifth person to walk on the Moon.

Shepard’s two spaceflights took place nearly 10 years apart and his differing experiences — one spaceflight a 15-minute orbital flight and the other a nine-day voyage to the Moon including nine hours of extravehicular activity on the lunar surface — showcase how far NASA’s human spaceflight capability had come in a single decade.