How Project Mercury Worked

Shepard's Freedom 7 Mission
Alan Shepard, the first American in outer space
Alan Shepard, the first American in outer space
Photo courtesy NASA

The goals of the Mercury space program were to orbit a manned spacecraft around the Earth, investigate man's ability to function in space and recover the man and spacecraft safely. By 1961, the race to accomplish these goals was in high gear because of the Cold War. The astronauts had been selected and trained, and the spacecraft built and tested. NASA officials, particularly the lead rocket scientist Wernher Von Braun, insisted that the booster/spacecraft be tested by flying chimpanzees into outer space. Two such flights occurred before it was certified as ready for a manned mission. While these tests were being conducted, the Soviets launched Cosmonaut Yuri Gagarin into Earth orbit. In April 1961, Gagarin became the first man to reach outer space. NASA was criticized by the press and public, who felt that the United States could have put a man in outer space before the Soviets. The Soviet achievement placed the United States far behind in the space race. NASA relied on astronaut Alan Shepard to put America back in the game.

On May 5, 1961, Alan Shepard climbed aboard his Mercury spacecraft, called Freedom 7. His mission was to fly into outer space and return safely in a sub-orbital flight that would last about 15 minutes. There were numerous delays in the countdown, and Shepard was on the pad for hours. Finally, at 9:43 AM, Alan Shepard was launched into outer space. Shepard reached an altitude of 116 miles (187 km) and landed 303 miles (488 km) down-range from Cape Canaveral, where he was recovered by the aircraft carrier Lake Champlain. He reached a peak velocity of 5,134 miles per hour (8,260 kph) and experienced a force as high as 11 Gs (11 times the acceleration due to gravity) upon re-entry. The flight lasted 15 minutes and 28 seconds. Unlike Gagarin, Shepard was able to maneuver the craft during flight. Shepard's historic flight launched the U.S. space program, ultimately, to the moon.

Alan Shepard during recovery (top) and on-board the carrier after his flight
Photo courtesy NASA
Alan Shepard during recovery (top) and on-board the carrier after his flight
Photo courtesy NASA

Alan Shepard was later grounded due to an inner-ear disorder. He worked in the Astronaut Office for many years before having surgery to correct his ear problem. He moved on to command the Apollo-14 mission and walk on the moon. He was the only Mercury astronaut to go to the moon, as well as the only man (to this day) to golf on the moon. Alan Shepard died in 1998.

Shepard's groundbreaking flight was followed by another sub-orbital flight by Gus Grissom and four orbital flights by Glenn, Carpenter, Schirra and Cooper (to learn about these subsequent Mercury missions, see How Project Mercury Missions Worked). The men and missions of Project Mercury established that America could place a person in orbit, that he could survive in space and that he could return successfully. Project Mercury established a foothold for America in the space race and paved the way for Projects Gemini and Apollo. As of 2001, Mercury astronauts Glenn, Carpenter, Schirra, and Cooper are still alive, although retired from space endeavors. The pioneering contributions of these men to aviation and space exploration will always be remembered.

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Other Great Links

Books and Videos


  • "The Right Stuff," by Tom Wolfe
  • "Deke!: U.S. Manned Space: From Mercury to the Shuttle," by Donald K. Slayton, Michael Cassutt (Contributor), Deke Slayton
  • "Schirra's Space," by Wally Schirra, Walter M. Schirra, Richard Billings (Contributor)
  • "Leap of Faith: An Astronaut's Journey into the Unknown," by Gordon Cooper, Bruce Henderson (Contributor)
  • "Flight: My Life in Mission Control," by Chris Kraft
  • "To Rise from Earth : An Easy-To-Understand Guide to Space Flight," by Wayne Lee

Videos: DVD

  • "The Right Stuff" (1983)
  • "From the Earth to the Moon," (1998)

Videos: VHS

  • "The Right Stuff" (1983)
  • "Moonshot" (1995)
  • "From the Earth to the Moon" (1998)
  • "In Search of Liberty Bell 7" (1999)