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|GE Apollo over Moon - The GE Apollo as it would appear on its circumlunar mission, with its protective shroud and solar power collector deployed.|
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Class: Manned. Type: Lunar orbiter. Nation: USA. Manufacturer: General Electric.
The General Electric design for Apollo put all systems and space not necessary for re-entry and recovery into a separate jettisonable 'mission module', joined to the re-entry vehicle by a hatch. Every gram saved in this way saved two or more grams in overall spacecraft mass. The 2183 kg re-entry vehicle used a shape of the highest possible volumetric efficiency and was only 2.88 m in diameter and 2.40 m high. The end result was remarkable. In comparison with the NASA final Apollo design, the General Electric D-2 provided the crew with 50% more living space, an airlock, and a service module for the mass of the Apollo capsule alone. Fueled for the circumlunar mission, the entire 10.18 m-long spacecraft weighed only 7,470 kg. But in the end, NASA administrator James Webb examined the model of the D-2, thanked the contractor for its efforts, and announced that Apollo would use the NASA design without any consideration of alternatives. The Soviet Union used the General Electric design approach for their Soyuz spacecraft, still in service 40 years later. The NASA Apollo deign was retired after 8 years.
The General Electric Apollo D-2 / Soyuz Design Concept
The fundamental concept of the General Electric design can easily be summarised as obtaining minimum overall vehicle mass for the mission. This is accomplished by minimising the mass of the re-entry vehicle. There were two major design elements to achieve this:
Put all systems and space not necessary for re-entry and recovery outside of the re-entry vehicle, into a separate jettisonable 'mission module', joined to the re-entry vehicle by a hatch. Every gram saved in this way saved two or more grams in overall spacecraft mass - for it did not need to be protected by heat shields, supported by parachutes, or braked on landing.
- Use a re-entry vehicle of the highest possible volumetric efficiency (internal volume divided by hull area). Theoretically this would be a sphere. But re-entry from lunar distances required that the capsule be able to bank a little, to generate lift and 'fly' a bit. This was needed to reduce the G forces on the crew to tolerable levels. Such a manoeuvre is impossible with a spherical capsule. After considerable study, the optimum shape was found to be the 'headlight' shape - a hemispherical forward area joined by a barely angled cone (7 degrees) to a classic spherical section heat shield.
|GE Apollo Cutaway - Cutaway view of GE Apollo D-2 Proposal|
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This design concept meant splitting the living area into two modules - the re-entry vehicle, with just enough space, equipment, and supplies to sustain the crew during re-entry; and a mission module. As a bonus the mission module provided an airlock for exit into space and a mounting area for rendezvous electronics.
The end result of this design approach was remarkable. The Apollo capsule designed by NASA had a mass of 5,000 kg and provided the crew with six cubic meters of living space. A service module, providing propulsion, electricity, radio, and other equipment would add at least 1,800 kg to this mass for the circumlunar mission. The General Electric D-2 provided the same crew with 9 cubic meters of living space, an airlock, and the service module for the mass of the Apollo capsule alone!
The modular concept was also inherently adaptable. By changing the fuel load in the service module, and the type of equipment in the mission module, a wide variety of missions could be performed.
In the United States, the earliest manned capsule ballistic designs already exhibited the range of shapes that would be flown later. In response to the US Air Force Manned Ballistic Rocket Research System request for proposal in February 1956, Lockheed, Martin, and Aeronautics proposed a blunted warhead re-entry vehicle form like that used later for the Discoverer/KH-4/Corona film recovery capsules and Biosatellite. McDonnell proposed a shape very like the later Soyuz ‘headlight’ (but with a heat shield that extended a bit around the base). Avco, Goodyear and Convair proposed spheres, like that used for the Vostok spacecraft in Russia. Bell, North American, Republic, and Northrop all proposed winged vehicles.
|GE Apollo vs Soyuz - Comparison of GE Apollo and Soyuz LOK lunar orbiter spacecraft.|
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NASA was handed all manned spaceflight projects when it was formed. Initial sketches of the Mercury spacecraft followed by McDonnell proposal and had the Soyuz shape. This was later modified to the simple conical hull of the Mercury capsule. Even while designing this capsule, NASA began considering manned spacecraft to follow the initial Mercury flights. In true government fashion this was determined by a series of committees. On 9 December 1959 the Goett Committee was formed to recommend a post-Mercury space program. After four meetings, they fixed on manned circumlunar flight and landings as a logical follow-on to Mercury. By July 1960, the name 'Apollo' was selected for the program and NASA sponsored its first conference with aerospace industry to outline its plans. On September 13 NASA held the first Apollo Bidder's Conference. Bidders for the study contracts were to concentrate on the following specification: Saturn C-2 compatibility (6,800 kg mass for circumlunar mission); 14 day flight time; three-man crew in shirt-sleeve environment (the three man crew was thought necessary so that they could alternate eight hour duty shifts). A month later, from among 16 bids, Convair, General Electric, and Martin were selected to conduct $250,000, six month study contracts.
|GE Apollo vs Soyuz - Comparison of GE Apollo and Soyuz reentry vehicles.|
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While this window-dressing was going on, NASA Langley had already decided what the design would be. Max Faget, together with designer Caldwell Johnson, had decided, in the words of Ulysses S Grant, 'it's not what you decide, it's to decide'. And they decided that their capsule would be conical and have a diameter of 160 inches to match the last stage of the Saturn C-2. Later, when the diameter of the C-2 was reduced to 154 inches they rounded the corners to fit. And that was it. While the contractors invested millions of their own money, studying alternatives, doing trade studies, Johnson had already produced design drawings virtually indistinguishable from the Apollo CM that would fly six years later. All of the anguishing discussions that would follow after the decision to go to the moon - the mode debate (direct landing vs. earth orbit rendezvous vs. lunar orbit rendezvous), the launch vehicle debate (Saturn C-3, C-4, C-5, Nova), and so on took as the starting point the 5,000 kg Langley Apollo capsule.
In blessed ignorance, General Electric Philadelphia plunged into the project. The Manager of GE Space Vehicle Systems, George Arthur, led a team that included Harold Bloom, Charles Bixler, Jacob Abel, and Arnold Cohen. GE brought to the project the greatest experience in re-entry vehicle technology of any of the study contractors. As early as 1956 GE's Richard Porter had done pioneering work for the US Air Force in solving the re-entry capsule problem. GE was the leading contractor to the Air Force for strategic missile re-entry vehicles, culminating in the enormous Mark. 6 re-entry vehicle for the 3,175 kg Titan II warhead. They also worked on a number of 'black' Air Force programs and provided NASA with the heat shield for the Mercury spacecraft.
|GE Apollo Proposal - Soyuz GE Apollo Proposal|
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GE accordingly attacked the re-entry vehicle problem with particular insight. They studied three semi-ballistic designs, derived from their work on classified projects. They also considered the winged, lifting body, and lenticular (winged flying saucer) configurations being pursued by the other contractors. For each possibility, two variations were considered: 'integral' (the entire work area was included in the capsule), and 'modular' (use of the mission module concept to minimise re-entry vehicle mass).
During the six months of the contractor study, the world changed.
Originally this work was being undertaken without any commitment from the government for the massive funding that would be required for the project. President Eisenhower was hostile to NASA spending enormous sums on spaceflight. After the November 1960 elections, NASA hoped that Kennedy would be more interested in their schemes for a costly manned space program. However they found Kennedy to be just as indifferent.
On April 12, Russia orbited Yuri Gagarin, the first man in space. Five days later the Kennedy administration suffered a humiliating defeat in the failed invasion of Cuba at the Bay of Pigs. Senators demanded action and held hearings on the Apollo project. NASA seized the day. Congressmen did not seem to blanch when NASA told them it would cost $20 to $40 billion to land on the moon by 1967 - maybe.
|GE Apollo Capsule - Cutaway views of GE Apollo D-2capsule.|
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On May 15 to 17 the contractors presented the results of their Apollo studies. Martin proposed a vehicle similar to the configuration that Faget had already selected. GE reported that their D-2 modular design provided the lowest mass and greatest flexibility. Convair proposed a lifting body concept. NASA administrator James Webb examined the model of the GE D-2, thanked the contractors for their efforts, and announced to the contractors that Apollo would use the Langley design without any consideration of their alternatives!
A week later Kennedy proclaimed the moon landing objective as a means of regaining American prestige. NASA plunged into furious action on the crash program. By 28 July Langley had taken the best bits of the study contractor's reports and generated the Apollo technical specification. Twelve contractors, including General Electric, were invited to bid no later than 9 September for the Apollo spacecraft. Following enormous efforts and intense behind-the scenes manoeuvring, the contractors grouped into politically saleable teams. GE teamed with Douglas, Grumman, and Space Technology Laboratories. The four other bids were from a General Dynamics / Avco team; a McDonnell / Lockheed / Hughes / Vought team; Martin; and North American.
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As is usual, the customer spent almost as much time studying the bids as the contractors spent creating them. On 24 November, reflecting mainly the extent to which each competitor had followed Langley's design, the formal bid evaluation was completed. The 'scientific' bid ratings were: Martin 6.9; General Dynamics 6.6; North American 6.6; GE 6.4; McDonnell 6.4. Martin was unofficially passed the word and announced to its cheering workers on 27 November that they had won the contract. However a funny thing happened on the way to the White House, and when the contract award was announced on 28 November, North American was awarded the prime contract. General Electric folded up its tents and went back to building re-entry vehicles for military programs. Seeking professional recognition for their work, Arthur and Abel publicly documented their D-2 design by presenting papers the following December at a special symposium of the American Astronautical Society in Denver, Colorado.
- 26 - Baker, David, The History of Manned Spaceflight, Crown, New York, 1981.
- 202 - Arthur, George R, Advanced in the Astronautical Sciences, Volume 10, "Lunar Spacecraft Designs", 1963, p. 52.
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Last update 12 March 2001.
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