Mercury-Atlas 8 (MA-8) was the fifth United States crewed space mission, part of NASA's Mercury program. Astronaut Walter M. Schirra Jr., orbited the Earth six times in the Sigma 7 spacecraft on October 3, 1962, in a nine-hour flight focused mainly on technical evaluation rather than on scientific experimentation. This was the longest U.S. crewed orbital flight yet achieved in the Space Race, though well behind the several-day record set by the Soviet Vostok 3 earlier in the year. It confirmed the Mercury spacecraft's durability ahead of the one-day Mercury-Atlas 9 mission that followed in 1963. Planning began for the third U.S. orbital mission in February 1962, aiming for a six-or-seven-orbit flight to build on the previous three-orbit missions. NASA officially announced the mission on June 27, and the flight plan was finalized in late July. The mission focused on engineering tests rather than on scientific experimentation. The mission finally launched on the morning of October 3, having been delayed two weeks because of problems with the Atlas booster. A series of minor booster problems during launch and a faulty temperature controller in Schirra's pressure suit were the only technical problems noted during the flight. The spacecraft orbited in both automated and passive flight modes for prolonged periods while the pilot monitored it and carried out some minor scientific experiments. After six orbits, the capsule landed in the Pacific Ocean half a mile from the recovery carrier, and was hoisted aboard for Schirra to disembark. The scientific results of the mission were mixed. The astronaut returned healthy after nine hours of confinement in a low-gravity environment. Observation of the Earth's surface proved unproductive, however, because of heavy cloud cover and bad photographic exposures. The public and political reaction was muted compared with that of earlier missions, as the Cuban Missile Crisis soon eclipsed the Space Race in the news. The mission was a technical success: all the engineering objectives were completed without significant malfunctions, and the spacecraft used even less fuel than expected. This confirmed the capabilities of the Mercury spacecraft and allowed NASA to plan with confidence for a day-long flight, MA-9, which had been an early goal of the Mercury program.
Mission parameters Mass: 1,964 kilograms (4,330 lb) Perigee: 156 km Apogee: 285 km Inclination: 32.5° Period: 88.91 min
Background
By 1962, both the United States and the Soviet Union had flown two solo spaceflights in the Space Race. There was a widespread perception, however, that the United States was falling behind; its two missions had been suborbital and had lasted only a few minutes. The Soviet missions had both orbited the Earth, and the second, Vostok 2, had remained in orbit for a full day. Using the new high-powered Atlas booster, the coming orbital Mercury missions were expected to reduce the gap between the two countries. NASA announced the first two orbital missions at the end of November 1961, shortly after the Mercury-Atlas 5 (MA-5) test flight, which had carried a chimpanzee and twice orbited the Earth. MA-6 was planned as the first orbital flight, with John Glenn as the primary crew and Scott Carpenter as his backup. The follow-up mission, MA-7, was to be crewed by Deke Slayton, with Wally Schirra as his backup. In February 1962, the first draft planning began for MA-8, the third orbital mission, with a goal of "six or seven" orbits, as an intermediate step towards a day-long 18-orbit flight. The decision to move to six orbits rather than seven was driven by the mission rules on contingency recovery operations; a seventh orbit would have required significant additional recovery forces to be able to reach the capsule anywhere on its trajectory within eighteen hours. The six-orbit profile had other effects on the recovery plans; the optimum recovery point was moved to the Pacific Ocean, rather than the Atlantic. On March 15, 1962, NASA announced that Slayton was medically unfit and would be replaced by Scott Carpenter as the prime crew for the MA-7 mission. The decision to replace him with Carpenter, rather than his official backup Schirra, was justified by the large amount of training Carpenter had managed while preparing for the long-delayed MA-6 mission. After the success of the MA-6 and MA-7 missions, both of three orbits, pressure began to mount to fly an extended mission. On June 27, 1962, NASA first announced its plan for the upcoming MA-8 mission, which would last for "as many as six" orbits. Schirra was named as the prime crew for MA-8, with Gordon Cooper as his backup, repeating the backup-one fly-one pattern set by the previous two missions. The pattern would be repeated for MA-9, flown by Cooper, and the planned but cancelled MA-10, which would have been flown by Cooper's backup, Alan Shepard. The Soviet Union had not flown any further flights by the time MA-7 landed, putting both sides of the Space Race even at two orbital flights each. While the Soviets had flown for longer, the Mercury program was gaining momentum, with a six-orbit mission currently planned and press speculation about a one-day mission. However, in mid-August, the Soviet Union launched two orbital missions, Vostok 3 and Vostok 4, within a day of each other. The two craft were in intersecting orbits, but despite much speculation did not attempt to rendezvous; they completed missions of 64 and 48 orbits respectively, just under four and three days, landing within a few minutes of each other on August 15. This was far ahead of anything currently planned for Mercury, and NASA quickly considered the prospect of modifying a capsule to have an active manoeuvring and rendezvous capability, using technology being developed for the Gemini program. However, after examining the time and safety implications of this proposal, it was decided to abandon the idea and continue with the planned six-orbit mission.
Mission objectives
… excerpt ends here. Continue reading the full article.
