Mercury project

• Project Mercury was the first human spaceflight program of the United States. It run from 1959 through 1963 with the goal of putting a human in orbit around the Earth. The Mercury-Atlas 6 flight on February 20, 1962, was the first American flight to achieve this goal.
• The program included 20 unmanned launches, followed by two suborbital and four orbital flights with astronaut pilots. Early planning and research were carried out by the National Advisory Committee for Aeronautics (NACA), but the program was officially conducted by its successor organization, NASA. Mercury laid the groundwork for Project Gemini and the follow-on Apollo moon-landing program.
• The project name came from Mercury, a Roman mythological god often seen as a symbol of speed. Mercury is also the name of the innermost planet of the Solar System, which moves faster than any other and hence provides an image of speed, although Project Mercury had no real connection to the planet.
• The goals of the program were to orbit a manned spacecraft around Earth, investigate the pilot's ability to function in space and to recover both pilot and spacecraft safely.
• NASA also established program guidelines: existing technology and off-the-shelf equipment should be used wherever practical, the simplest and most reliable approach to system design would be followed, an existing launch vehicle would be employed to place the spacecraft into orbit, and a progressive and logical test program would be used.
• Project requirements for the spacecraft were that it must be fitted with a reliable launch escape system to separate the spacecraft and its astronaut from its launch vehicle in case of impending failure; the pilot must have been given the capability of manually controlling the attitude of the spacecraft; the spacecraft must carry a retro-rocket system capable of reliably providing the necessary impulse to bring the spacecraft out of orbit; a zero-lift body utilizing drag braking to be used for reentry; and that the spacecraft design must satisfy the requirements for a landing on water.
• Contractors:
  • On 7 October 1958, T. Keith Glennan, the first administrator of NASA, approved the Mercury project. On December 17 Glennan announced Project Mercury publicly.
  • On 29 December 1958 North American Aviation was awarded a contract to design and build Little Joe launch vehicles to be used for altitude flight testing of the Mercury launch escape system. In January 1959 McDonnell Aircraft Corporation was chosen to be prime contractor for the Mercury spacecraft, and the contract for 12 spacecraft was awarded in February. In April seven astronauts, known as the Mercury Seven or more formally as Astronaut Group 1, were selected to participate in the Mercury program.
    

    L to R: Grissom, Shepard, Carpenter, Schirra, Slayton, Glenn, Cooper, 1962

    1. retrorockets, 2. heatshield, 3. crew compartment, 4. recovery compart., 5. antenna section, 6. escape tower

    
    
  • In May 1959 North American Aviation delivered the first two Little Joes, and in June, an Atlas D launch vehicle named Big Joe was delivered, for use in a suborbital heat shield test flight. In July, the planned use of the Jupiter rocket as a suborbital launch vehicle was changed to the Redstone. In October General Electric delivered to McDonnell the ablative heat shield designated for installation on the first Mercury spacecraft. In December the launch vehicle for Mercury-Redstone 1 was ready to begin static tests installed on a test stand at ABMA.
  • In January 1960 NASA awarded Western Electric Company a contract for the Mercury tracking network. The value of the contract was over $33 million. Also in January, McDonnell delivered the first production-type Mercury spacecraft, less than a year after award of the formal contract. On February 12, Christopher C. Kraft, Jr. was appointed to head the Mercury operations coordination group. In April, the first spacecraft was delivered to Wallops Island for the beach-abort test. The test was completed successfully on May 9.

Mercury diagram

Unmanned flights:

• The program included 20 robotic launches. Not all of these were intended to reach space and not all were successful in completing their objectives. Four of these flights included non-human primates, starting with the fifth flight (1959) which launched a Rhesus macaque named Sam (after the Air Force's School of Aerospace Medicine). The Mercury program's complete roster of non-human space-farers is given below:
  • Sam, a Rhesus macaque, launched 4 December 1959 on Little Joe 2 to 85 km altitude.
  • Miss Sam, a Rhesus macaque, launched 21 January 1960 on Little Joe 1B to 15 km altitude.
  • Ham, a chimpanzee, launched 31 January 1961 on Mercury-Redstone 2 for a suborbital flight.
  • Enos, a chimpanzee, launched 29 November 1961 on Mercury-Atlas 5 for a 2-orbit flight.
• All missions were named after the rocket used and the number of missions reached by that rocket. The Redstone and Atlas rockets were meant for manned flights but they had to be tested in unmanned flights first. Therefore the first manned mission with the Redstone rocket was Mercury-Redstone 3 and the first with Atlas, the Mercury-Atlas 6

Manned flights:

• The first Americans to venture into space were drawn from a group of 110 military pilots chosen for their flight test experience and because they met certain physical requirements. NASA announced the selection of seven of these, known as the Mercury Seven, as astronauts on 9 April 1959, though only six of the seven flew Mercury missions, after Slayton was grounded due to a heart condition. In order of flight:
  • Alan Bartlett Shepard, Jr., USN (1923-1998); first American in space, May 1961
  • Virgil Ivan "Gus" Grissom, USAF (1926-1967); flew 21 July 1961. Died during Apollo 1 pre-launch test
  • John Herschel Glenn, Jr., USMC (born 1921); first American to orbit the Earth, 20 February 1962
  • Malcolm Scott Carpenter, USN (born 1925), flew 24 May 1962
  • Walter Marty "Wally" Schirra, Jr., USN (1923-2007), flew 3 October 1962
  • Leroy Gordon "Gordo" Cooper, Jr., USAF (1927-2004), flew 15 May 1963
  • Donald Kent "Deke" Slayton, USAF (1924-1993); grounded in 1962, but reinstated in 1972 and flew on the Apollo-Soyuz Test Project in 1975
• Just like the rockets and spacecraft were tested in details by unmanned flights, the astronauts went through a training program in special facilities and model arrangements. Some tests were made to see their response to weightlessness on one hand and high g forces on the other. Other parts of the training was meant to give them practice in maneuvering the spacecraft and get in and out of its narrow openings wearing a space suit.
• In all, 6 manned missions were made. The most famous flights were the first and the third. On 05-May-1961, less than four weeks after Gagarin's flight, Alan B. Shepard became the first US astronaut. While he did not orbit the Earth, he reached an altitude of some 186 km.
  Shepard, launched from Cape Canaveral in Mercury 3 atop a modified Redstone ballistic missile, spent 15 min 22 s in flight before landing in the Atlantic. He proved that a man could manually control a spacecraft though he is weightless.
  Mercury's first orbital flight came on 20-Feb-1962. John Glenn was launched in Mercury 6 by a modified Atlas ICBM from Cape Canaveral. Glenn spent only 4 hr 55 min circling the Earth, completing just three orbits before landing safely. Glenn's objective was to evaluate man in Mercury. Although he had some trouble adjusting to the use of the hand control during reentry, the mission was a success. Subsequent missions were to verify the man-machine concept upon which Mercury was designed.
  Three more orbital flights were made, the last in 1963.
• 2 suborbital flights were cancelled; they began to look embarrassing after Soviet had made a day long orbital flight in August 1961. Three orbital flights were also cancelled since it was clear that the spacecraft had reached its limits. At the last flight the batteries were exhausted before reentry but, luckily, the spacecraft landed safely.
• Beginning with Alan Shepard's Freedom 7 flight, the astronauts named their own spacecraft, and all added "7" to the name to acknowledge the teamwork of their fellow astronauts.

Tracking network:

• To track the manned orbit missions a network of radio stations was built around the equator. Two other tracking networks already existed: one for unmanned missions and one for deep space missions, however they were not adequate for manned missions.
• Deep space missions require a few big telescopes whereas earth orbit manned missions require many small radiostations at points that the spacecraft will pass over on its way. Unmanned missions need the same kind of radio stations but in smaller number. These differences led NASA to build an independent network for the manned missions

Control Center, Florida

The 6 orbits and tracking stations

External links:

• SCRIBD: Mercury Chronology - NASA SP-4001
• Drewexmachina.com: Mercury program