Mercury-Atlas 8
Mission type | Test flight |
---|---|
Operator | NASA |
Harvard designation | 1962 Beta Delta 1 |
COSPAR ID | 1962-052A |
SATCAT no. | 433 |
Mission duration | 9 hours, 13 minutes, 15 seconds[1] |
Orbits completed | 6 |
Spacecraft properties | |
Spacecraft | McDonnell Aircraft |
Launch mass | 1,964 kilograms (4,329 lb) |
Landing mass | 1,110 kilograms (2,440 lb) |
Dry mass | 1,242–1,374 kilograms (2,739–3,029 lb) |
Crew | |
Crew size | 1 |
Members | |
Callsign | Sigma 7 |
Start of mission | |
Launch date | October 3, 1962, 12:15:12 LC-14 | UTC
End of mission | |
Recovered by | USS Kearsarge |
Landing date | October 3, 1962, 21:28:22[1] | UTC
Landing site | Central Pacific Ocean |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth orbit |
Perigee altitude | 156 kilometers (84 nmi) |
Apogee altitude | 285 kilometers (154 nmi) |
Inclination | 32.5 degrees |
Period | 88.91 minutes |
Epoch | October 3, 1962[3] |
Walter "Wally" Marty Schirra Jr. Project Mercury Crewed missions |
Mercury-Atlas 8 (MA-8) was the fifth
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
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
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.[5] 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.[6] 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.[7]
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.[8] 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.[9] 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.[10] 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.
Mission objectives
The original MA-8 flight plan was issued on July 27; although it was revised slightly in August and September, it remained broadly unchanged until launch. This was an improvement on the situation with MA-7, which had had frequent and extensive alterations, making it difficult for the pilot to train efficiently. The aim was for the flight to be an engineering-oriented mission, focusing on the operation of the spacecraft rather than on scientific experimentation, to help pave the way for a future long-duration mission.[13]
The mission objectives involved evaluating the performance of the spacecraft over six orbits, as well as the effect of prolonged microgravity on the pilot. The specific spacecraft systems would also be evaluated and tested, and the worldwide tracking and communications network would be tested to see how well it would stand up in an extended mission.[14] The flight control experiments included manually turning the spacecraft around, yaw and pitch manoeuvres to determine how easy it was to control the spacecraft attitude, realignment of the onboard gyroscopes in flight, and leaving the spacecraft to drift on-orbit.[15]
Four non-engineering scientific experiments were planned, two requiring the active involvement of the astronaut and two completely passive. The first involved the astronaut watching for four high-powered flares while passing over
Naming
For his spacecraft, Schirra originally favored the name Phoenix, while his wife championed Pioneer. He ultimately dubbed the vessel Sigma 7 because, as the mathematical symbol for the summation of elements, the name reflected that "the flight was the sum of the efforts and energies of a lot of people."
The seven appended to the end was in honor of the seven original astronauts selected for Mercury, a tradition inadvertently started by prior Mercury pilot, Alan Shepard, who incorporated the seven in "Freedom 7" as his spacecraft was factory model no. 7. The other astronauts liked the symbolism, and so each added 7 to their spacecraft names as well.[19]
Spacecraft modifications
The spacecraft and booster were almost identical to those used on the two preceding Mercury orbital flights. The spacecraft had heating blankets removed from the
The Atlas booster (Vehicle 113D) had been modified since the previous flight, and now included baffled
Mission preparation
The capsule built for the mission, Mercury Spacecraft No. 16, had been delivered to
Concerns had been raised that the radiation belt produced in orbit by the recent
Schirra began training for the mission in early July, logging 29 hours in simulators as well as 31 hours in the spacecraft itself. This included multiple systems tests and three simulated flights, culminating in a six-and-a-half-hour simulated flight on September 29, with the spacecraft and booster fully stacked on the pad.[30] Highlights of the training period included a visit from President John F. Kennedy on September 11.[31]
The mission was reported as ready to go—"except for the weather"—on October 1. The major concern with the weather was a major tropical storm in the Atlantic, though there were also worries over a series of typhoons in the Pacific which could pose a problem for recovery operations. On the evening of October 2, the decision was taken to launch the next morning.[32]
Launch
Schirra was awakened at 1:40 am ET on the morning of October 3, and after a hearty breakfast—including a
Around three and a half minutes into the flight,
Because the Atlas was flying on a slightly lofted trajectory, the booster engines cut off 2 seconds earlier than planned, but the sustainer engine burned for about 10 seconds longer than intended, giving an extra 15 feet per second (4.6 m/s) of velocity and putting the spacecraft in a slightly higher orbit than planned.[35] Initial analysis of the trajectory confirmed that the capsule could remain in a stable orbit for at least seven orbits, ensuring there would be no need for an early de-orbit.[39]
Orbital activities
After separating from the Atlas booster, Schirra stabilized the spacecraft and slowly cartwheeled into the correct attitude; he deliberately kept the motion slow to conserve fuel, and was able to position the capsule using half a percent of his fuel reserves.[35] He briefly tracked the spent booster, which was rotating slowly past, but made no attempt to move towards it. As the spacecraft moved across the Atlantic, he turned his attention to testing manual control of the spacecraft, which he found sloppy compared to the fly-by-wire system.[40]
Crossing over the eastern coast of Africa, he began to feel overheated; this problem was also apparent to the ground controllers, who were having a debate with the flight surgeon over whether it was safe to continue or if the mission should be ended after the first orbit. The flight director, Christopher Kraft, followed the surgeon's advice to see if the problem would settle, and gave the go for a second orbit.[41] Schirra eventually stabilized the problem over time, slowly dialing the suit's control knob to a high cooling setting;[42] he compared the heat to that of "mowing a lawn in Texas".[43]
Over Australia, Schirra watched for a flare launched from the ground, but it was occluded by clouds; he was, however, able to see lightning and the lit outline of
On the second orbit, he confirmed the existence of Glenn's "fireflies", the shower of small bright particles first reported on MA-6, and during the night section practiced yaw manoeuvres using first the Moon and then known stars as reference points. The second proved difficult to work with, as the small windows of the Mercury capsule gave a very limited field of view, making it hard to identify constellations. Travelling across the Pacific, he again fell back into automatic flight, chatting with Gus Grissom at the Hawaiian tracking station about the qualities of the manual control system.[44]
As he began the third orbit, Schirra disconnected the spacecraft's
On the fourth orbit, drifting in an inverted spacecraft with the Earth 'above' him, Schirra continued his photography and attempted—unsuccessfully—to spot the
By the fifth orbit, Schirra had begun to relax, commenting that it was the first rest he had had since December 1961. He used a small
The sixth orbit was dominated by preparations for re-entry, though Schirra was able to take a last set of photographs of South America and try another set of spatial-orientation tests. He armed the
Reentry and recovery
As the spacecraft continued towards
The local recovery group in the prime target area, in the central Pacific, consisted of an aircraft carrier, USS Kearsarge, in the center of the landing area, with three destroyers strung out along the orbital path. Four search aircraft were also assigned to the area, and three recovery helicopters were based aboard Kearsarge.[52]
Kearsarge picked up the capsule on radar while still 200 miles (320 km) from landing; 90 miles (140 km) further up the landing path, the destroyer
Forty minutes after landing, Sigma 7 was hoisted aboard Kearsarge; five minutes later, Schirra blew the explosive hatch and climbed out to a waiting crowd.
The spent Atlas booster re-entered the atmosphere on October 4, the day after the launch, and burned up.[57]
Post-flight
The post-flight analysis reported no major malfunctions—the only troublesome anomaly being the suit temperature controls— and all the engineering objectives of the mission were deemed successfully completed.[14] The fuel-conservation measures were found to have worked particularly well, with even less fuel than anticipated being consumed; despite the technical changes, the official report gave full credit for this to the pilot.[58] The medical analysis found no significant physiological effects from nine hours of weightlessness, and noted that Schirra had received no significant radiation exposure.[59] Analysis of the radiation-sensitive plates confirmed that there had been a very low radioactive flux inside the spacecraft,[60] and the six ablative materials tested were all deemed broadly satisfactory despite some difficulty comparing them to each other.[61]
Scientifically, the light-observation experiments were unsuccessful, as both target locations were covered by thick cloud cover. However, Schirra was able to view lightning near Woomera, and noted the lights of a city a few hundred miles from Durban.[16] The filtered photography for the Weather Bureau worked as planned, with 15 photographs taken; the conventional color photography was less successful, with several of the 14 photographs unusable due to overexposure or excess cloud cover.[62] In the end, the conventional photographs were not used for scientific examination due to these problems.[63] Schirra noted that the sheer amount of cloud coverage, worldwide, could provide problems for future activity of this kind; however, Africa, and the south-western United States, were perfectly clear. Postflight medical examination of Schirra disclosed nothing significant other than a degree of orthostatic hypotension caused by sitting inside the cramped capsule for hours.[64]
Schirra's post-flight report noted the "fireflies" seen on the previous two missions, and emphasized the remarkable visual effect of the thick band of the atmosphere visible around the horizon.
Schirra gave a public lecture at Rice University after returning to Houston, where he received a motorcade through the city.[69] However, the Cuban Missile Crisis had been steadily escalating through September, and helped drive discussion of Schirra's successful flight down the news schedules; public concern about the relative effectiveness of Soviet and American space launchers was displaced by a more pressing concern over Soviet military rockets.[70] He visited Washington, D.C., to receive the NASA Distinguished Service Medal from President Kennedy on October 16, the same day Kennedy had first seen U-2 photographs of missile sites in Cuba; the meeting was friendly and informal despite the circumstances. Robert F. Kennedy, Schirra later noted, took him aside and sounded him out about a potential political career, the same way he had sounded out John Glenn a year earlier. Unlike Glenn, however, Schirra politely turned the suggestion down, and chose to remain with NASA.[71] His later career saw him commanding the backup crew for the first Gemini mission in 1965, then the prime crew for the Gemini 6A mission later that year, where he flew the first active rendezvous between two spacecraft—earlier plans for it to conduct the first on-orbit docking had been cancelled—and finally commanding the first Apollo mission, Apollo 7, in 1968. He retired from NASA in the summer of 1969, the only astronaut to fly on Mercury, Gemini, and Apollo.[72]
The success of MA-8 made the preparation for MA-9 "considerably easier",[70] though it did cause some observers to suggest the program should be ended abruptly in order to conclude on a clear note of success, rather than risking another—potentially catastrophic—flight.[73] However, this was not a view shared by the NASA planners, who had been pressing for a one-day Mercury mission since mid-1961, when it first began to seem technically feasible.[74] To prepare the spacecraft for a long-duration mission involved trimming as much on-board weight as possible to offset the additional consumables required. The changes made to the capsule hardware on MA-8 were now used to justify the removal of 12 pounds (5.4 kg) of control equipment and 5 pounds (2.3 kg) of radio equipment, as well as the 76 pounds (34 kg) periscope which Schirra had found so unhelpful. In total, there were 183 alterations listed between the capsules for the MA-8 and MA-9 missions.[75] The spacecraft was to be equipped with several cameras, building on Schirra's photographic work, though weight and power limitations did restrict the amount of scientific experiments that could be scheduled.[76]
Spacecraft location
After display at the
Notes
- ^ a b Boynton, p. 34
- ^ Boynton, p. 3
- ^ McDowell, Jonathan. "SATCAT". Jonathan's Space Pages. Retrieved March 23, 2014.
- ^ This New Ocean, p. 411
- ^ This New Ocean, p. 407.
- ^ This New Ocean, p. 462
- ^ This New Ocean, p. 464
- ^ This New Ocean, p. 440
- ^ This New Ocean, p. 443
- ^ This New Ocean, p. 460
- ^ This New Ocean, pp. 459–460
- ^ This New Ocean, pp. 461–2
- ^ This New Ocean, p. 461
- ^ a b Results of the third U.S. manned orbital space flight, p. 1
- ^ Results of the third U.S. manned orbital space flight, pp. 42–5
- ^ a b Results of the third U.S. manned orbital space flight, p. 8
- ^ Results of the third U.S. manned orbital space flight, pp. 8–9
- ^ Results of the third U.S. manned orbital space flight, pp. 9–10
- ^ Dora Jane Hamblin (11 October 1968). "Spacecraft Anonymous". life. pp. 107–116.
- ^ Results of the third U.S. manned orbital space flight, p. 2
- ^ Results of the third U.S. manned orbital space flight, p. 3
- ^ Results of the third U.S. manned orbital space flight, p. 4
- ^ Results of the third U.S. manned orbital space flight, p. 10
- ^ Grimwood, p. 157
- ^ Grimwood, p. 169
- ^ This New Ocean, p. 467
- ^ Grimwood, p. 170
- ^ Grimwood, pp. 171–2
- ^ Grimwood, p. 170. To put this in context, an unprotected dose of 500 röntgens over a few hours would be easily fatal.
- ^ Results of the third U.S. manned orbital space flight, p. 40
- ^ Results of the third U.S. manned orbital space flight, p. 39
- ^ This New Ocean, p. 471
- ^ This New Ocean, pp. 471–2
- ^ This New Ocean, p. 472
- ^ a b c This New Ocean, p. 473
- ^ Results of the third U.S. manned orbital space flight, p. 11
- ^ Results of the third U.S. manned orbital space flight, p. 57
- ^ Schirra's Space, pp. 91–92
- ^ Results of the third U.S. manned orbital space flight, p. 51
- ^ This New Ocean, p. 474. Schirra noted after his flight that a rendezvous in orbit would certainly be possible, given sufficient fuel and precise positioning information; he would later go on to fly the Gemini 6A mission, the first successful close rendezvous of two spacecraft.
- ^ This New Ocean, p. 474
- ^ a b This New Ocean, p. 475
- ^ This New Ocean, p. 476
- ^ This New Ocean, pp. 476–7
- ^ This New Ocean, p. 478
- ^ This New Ocean, pp. 479–80
- ^ This New Ocean, pp. 480–1
- ^ Results of the third U.S. manned orbital space flight, p. 111
- ^ Schirra's Space, p. 88
- ^ This New Ocean, pp. 481–82
- ^ This New Ocean, p. 482
- ^ Results of the third U.S. manned orbital space flight, p. 20
- ^ This New Ocean, pp. 482–3
- ^ This New Ocean, p. 484
- ^ Results of the third U.S. manned orbital space flight, p. 22
- ^ Grimwood, p. 174
- ^ p. 31, Barhorst, L.J.C. (2007). "Royal Aeronautical Establishment satellite tables, 1962". Retrieved 2010-02-13.
- ^ Results of the third U.S. manned orbital space flight, pp. 3–4
- ^ Results of the third U.S. manned orbital space flight, p. 23
- ^ Boynton, pp. 74–75. Further analysis was presented by Hermann J. Schaeffer in Proton dosimetry with nuclear emulsions on mercury missions MA-8 and MA-9 at the twelfth Annual Meeting of the Radiation Research Society, 1964.
- ^ Boynton, pp. 75–77
- ^ Results of the third U.S. manned orbital space flight, p. 9
- ^ Boynton, p. 74
- ^ Results of the third U.S. manned orbital space flight, p. 52
- ^ Results of the third U.S. manned orbital space flight, p. 53
- ^ This New Ocean, p. 477
- ^ Results of the third U.S. manned orbital space flight, p. 55. The Bearcat was the first fighter Schirra had flown after training, and he remembered it as "not a plane you climb into; rather, you strap it on". (Schirra's Space, p. 24)
- ^ First US crewed six-pass orbital mission, p. 53
- ^ Schirra's Space, p. 91
- ^ a b This New Ocean, p. 486
- ^ Schirra's Space, p. 92
- ^ Gray, Tara. "Walter M. Schirra Jr". NASA. Archived from the original on 2004-11-03. Retrieved 2010-02-13.
- ^ This New Ocean, pp. 486–7
- ^ This New Ocean, p. 487
- ^ This New Ocean, p. 490
- ^ This New Ocean, pp. 491–492
- ^ "Early Alabama Space and Rocket Center Souvenir Booklet". Heroic Relics. Retrieved April 23, 2012.
- ^ Gerard, James H. (2007). "Sigma 7 display page". A Field Guide to American Spacecraft. Archived from the original on 2012-05-06. Retrieved 2010-02-13.
References
- Grimwood, J. M. (1963). Project Mercury: a Chronology. NASA.
- Alexander, C. C.; Grimwood, J. M.; Swenson, L. S. (1966). This New Ocean: a History of Project Mercury. NASA.
- Results of the third U.S. manned orbital space flight. NASA. 1962.
- Boynton, J. H. (1968). First U.S. crewed six-pass orbital mission. NASA. hdl:2060/19680025550.
- Schirra, Walter M., & Billings, Richard N. (1988). Schirra's space. Boston: Quinlan Press. ISBN 1-55770-034-6.)
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: CS1 maint: multiple names: authors list (link
External links
- Media related to Mercury-Atlas 8 at Wikimedia Commons