|
Project Mercury was the United States' first manned spaceflight program. It ran from 1959 through 1963 with the goal of putting a man in orbit around the Earth. Early planning and research was carried out by NACA, while the program was officially carried out by the newly created NASA. The name comes from Mercury, a Roman mythological god who is often seen as a symbol of speed. Mercury is also the name of the innermost planet of the solar system, which revolves around the sun faster than any other, hence the image of speed, although Project Mercury had no other connection to that planet. The Mercury program cost $1.5 billion. See NASA Budget. Spacecraft It was said that the Mercury spacecraft were not ridden, they were worn, because of their extremely small size - at 1.7 cubic metres in volume, the capsule was just large enough for the single crew member. Inside were 120 controls: 55 electrical switches, 30 fuses and 35 mechanical levers. The spacecraft was designed by Max Faget and NASA's Space Task Group. During the launch phase of the mission, the Mercury spacecraft and astronaut were protected from launch vehicle failures by the Launch Escape System. The LES consisted of a solid fuel, 52,000 lbf (231 kN) thrust rocket mounted on a tower above the spacecraft. In the event of a launch abort, the LES fired for 1 second, pulling the Mercury spacecraft away from a defective launch vehicle. The spacecraft would then descend on its parachute recovery system. After booster engine cutoff (BECO), the LES was no longer needed and was separated from the spacecraft by a solid fuel, 800 lbf (3.6 kN) thrust jettison rocket that fired for 1.5 seconds. To separate the Mercury spacecraft from the launch vehicle, the spacecraft fired three small solid-fuel, 400 lbf (1.8 kN) thrust rockets for 1 second. These rockets are called the Posigrade rockets. The spacecraft was only equipped with attitude control thrusters - after orbit insertion and before retrofire they could not change their orbit. There were three sets of high and low powered automatic control jets and separate manual jets - one for each axis (yaw, pitch and roll), supplied from two separate fuel tanks - one automatic and one manual. The pilot could use any one of the three thruster systems and fuel them from either of the two fuel tanks to provide spacecraft attitude control. The Mercury spacecraft were designed to be totally controllable from the ground in the event that the space environment impaired the pilot's ability to function. The spacecraft had three solid-fuel, 1000 lbf (4.5 kN) thrust retrorockets that fired for 10 seconds each. One was sufficient to return the spacecraft to earth if the other two failed. The firing sequence (known as ripple firing) required firing the first retro, followed by the second retro five seconds later (while the first was still firing). Five seconds after that, the third retro fired (while the second retro was still firing). There was a small metal flap at the nose of the spacecraft called the "spoiler". If the spacecraft started to reenter nose first (another stable reentry attitude for the capsule), airflow over the "spoiler" would flip the spacecraft around to the proper, heatshield-first reentry attitude. During reentry, the astronaut would experience about 4 g-forces. Initial designs for the spacecraft suggested the use of either beryllium heat-sink heat shields or an ablative shield. Extensive testing settled the issue - ablative shields proved to be reliable (so much so that the initial shield thickness was safely reduced, allowing a lower total spacecraft weight), easier to produce (at that time, beryllium was only produced in sufficient quantities by a single company in the US) and cheaper. NASA ordered 20 production spacecraft, numbered 1 through 20, from McDonnell Aircraft Company, St. Louis, Missouri. Five of the twenty spacecraft were not flown. They were Spacecraft A number of boilerplate spacecraft (mockup/prototype/replica spacecraft, made from non-flight materials or lacking production spacecraft systems and/or hardware) were also made by NASA and McDonnell Aircraft and used in numerous tests, including launches. Boosters
Unpiloted 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 Aviation Medicine). The Mercury program's complete roster of non-human space-farers is given below: Astronauts
Piloted Mercury launches Mercury Flight insignias Flight patches that surport to be patches from various Mercury missions are available to the public. In reality, these patches were designed by private entrepreneurs long after the Mercury program ended. When genuine flight patches were created by crews in the Gemini program, this caused a public demand for Mercury flight patches, which was filled by these private entrepreneurs. The only patches the Mercury astronauts wore were the NASA logo and a name tag. Each manned Mercury spacecraft, however, was decorated with a flight insignia. These are the genuine Mercury flight insignias. Miscellaneous The Mercury astronauts trained, in part, at NASA Langley Research Center in Hampton, Virginia, under Flight Surgeon William K. Douglas and Keith G. Lindell (COL, USAF). Several bridges throughout the city bear the name of the Mercury astronauts, and a major north-south route in the cities of Hampton and Newport News is named Mercury Boulevard, honoring the Mercury program. The names of five of the Mercury astronauts are also commemorated in the popular 1960s TV show Thunderbirds. In the series, Jeff Tracy, the founder of the fictional International Rescue organisation, is a millionaire ex-astronaut who has named his five sons -- Scott, Virgil, Alan, John and Gordon -- after the real-life Mercury astronauts. Further reading See also | |||||||||||
|
| ||||||||||||
 |
|
| |