Apollo D-2

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The Apollo D-2 spacecraft was a design proposal submitted in May 1961 by General Electric (GE) to NASA in a manned lunar orbiter spacecraft feasibility study for the Apollo program, along with several other submissions. GE's three part modular design used a bullet-shaped command module (reentry cabin), with a separate mission module cabin and a cylindrical propulsion module. NASA decided to use its own two part design by Maxime Faget, which used a cone-shaped command module, supported by a service module containing propulsion and supporting equipment. GE later entered the spacecraft procurement competition, losing to North American Aviation.

GE publicly presented its design to the American Astronautical Society in December 1961. Similarities in the basic mission-command-propulsion module design have been noted to the Soviet Union's Soyuz spacecraft designed by Sergei Korolev and Vasily Mishin. It has been speculated that Korolev and Mishin could have incorporated GE design elements in the existing OKB-1 Sever designs (1959-1962) [1] that eventually became the cancelled Soyuz-A (7K) (1963) and approved Soyuz 7K-OK (1965-1967).[2][3] A Soyuz variant Soyuz 7K-L1 for the Zond program would later be built as part of the Soviet manned lunar programs.[4]

Apollo feasibility studies[edit]

In July and August 1960, NASA's Space Task Group hosted a series of NASA-industry conferences to discuss post-Project Mercury manned spacecraft plans. On August 30, NASA presented plans to award three feasibility study contracts for the Apollo spacecraft, conceived as a three-man Earth orbital and circumlunar craft, with growth potential for manned lunar landings.[5] A Request For Proposal was issued on September 12, and fourteen bids were received by October 9. On October 25, NASA awarded the $250,000, six-month contracts to General Dynamics/Convair, General Electric, and the Glenn L. Martin Company.[6] Meanwhile, members of the Space Task Group performed their own spacecraft design studies, to serve as a gauge to judge and monitor the three industry designs.[6]

All three competitors supplemented the $250,000 contracts with their own money: Convair spent $1 million, GE $2 million, and Martin $3 million.[7] The Manager of GE Space Vehicle Systems (Philadelphia), George Arthur, led the GE proposal team that included Harold Bloom, Charles Bixler, Jacob Abel, and Arnold Cohen. On May 15 to 17, 1961, the contractors presented their study results to NASA. All three designs employed a mission module cabin separate from the command module (piloting and re-entry cabin), and a propulsion and equipment module. Martin studied three different reentry module shapes, including a conical capsule vehicle similar to the STG configuration. GE also studied several reentry module shapes. GD/Convair's proposal employed a lifting body shape.[7]


GE D-2[edit]

Cross section of the GE D-2 submission, showing complete spacecraft and descent module

The GE D-2 design is notable in that it separates the descent module from the mission module for significant weight savings in the parachute and ablative heat shield. The D-2 design consisted of three modules: a lower engine module, the lightweight headlight shaped descent module with hatch, and upper mission module that held the heavy life support and avionics and could also be de-pressurized to double as an airlock.

By jettisoning the mission module during descent, it would significantly lighten the descent module, reducing the amount of heavy ablative heat shielding needed for descent. This lighter descent module meant that a greater payload of supplies such as oxygen, water or scientific instruments could be carried into space using the Saturn rocket.[8][not in citation given] It also allowed for approximately 50% greater habitable (pressurized) volume than the final Apollo design.[citation needed] This contrasted sharply with the final Apollo design chosen by NASA, which reentered through the atmosphere the entire weight of the heavy life support and avionics system used during the bulk of the mission.[2][dubious ]

Seeking professional recognition for their design work on the GE proposal, George Arthur and Jacob Abel publicly presented their papers documenting the GE D-2 design in December 1961 at a special symposium of the American Astronautical Society in Denver, Colorado.[9]



Apollo spacecraft procurement competition[edit]

On May 25, 1961, one week after presentation of the feasibility study results, President John F. Kennedy proposed the Moon landing objective to the US Congress, and by the end of May, Apollo effectively entered the procurement phase.[10][11] By this time, NASA had decided to abandon the mission module[citation needed], and fixed the reentry module configuration to the conical shape designed by Maxime Faget.

NASA awarded the contract for the Apollo Command/Service Module to North American Aviation on November 28, 1961, when it was still assumed the lunar landing would be achieved by direct descent or earth orbit rendezvous rather than by lunar orbit rendezvous.[12][13] Therefore design proceeded without a means of docking the Command Module to a Lunar Excursion Module (LEM). In the summer of 1962, the selection of the Lunar Orbit Rendezvous (LOR) proposal from NASA's Langley Research Center[14] made it clear that substantial redesign would be required to incorporate a mission module (LEM). By 1963, NASA decided the most efficient way to keep the Apollo program on track and address technical obstacles encountered in some subsystems (such as environmental control) was to proceed with the development of two CM/SM versions (Block I and Block II).[15]

Similarity to Soyuz[edit]

The Soyuz TMA spacecraft uses a separate orbital (mission) module in front of a descent module shaped similarly to that of the GE D-2.

Similarities have been noted between the GE D2 design and the Russian Soyuz spacecraft, which was designed and built after George Arthur and Jacob Abel's AAS presentation (Denver, CO) in December 1961.[9] In particular, Soyuz uses an orbital module located in front of the descent module, which uses a similar sphere-cone-sphere shape.

Victor Minenko, one of the OKB-1 designers with Korolev in 1950s and 1960s, who was active with RSC Energia in 1993, noted that in 1961 there were 40 people in several departments working on early designs and versions of the eventual Soyuz. "We use to read carefully the U.S. literature by the leading astrodynamicists - Ferri, Chapman, Van Driest, Lees, and the top Russians - Sibulkin, Koropkin". Vassily Mishin, chief Soyuz designer after Korolev's death, noted that a logical comparison of the Soyuz was to the US Apollo command/service module, since both were designed for lunar transport.[1]

In 1983, Phillip S Clark and Ralph F Gibbons discussed the Russian Soyuz program development (1963-1967) and adaptation of design elements from other programs and studies (Soviet and foreign).[2]

A similar modular design was used in the Russian Progress spacecraft (essentially the unmanned version of Soyuz), the Chinese Shenzhou spacecraft, and the planned Indian ISRO Orbital Vehicle.[16]

See also[edit]


Inline citations
  1. ^ a b James Harford (1997). Korolev. John Wiley &Sons. pp. 254–256. 
  2. ^ a b c Clark, Phillip S.; Gibbons, Ralph F. (October 1983). "The Evolution of the Soyuz Program". Journal of the British Interplanetary Society, (British Interplanetary Society) 36 (10): 443. 
  3. ^ Wachtel, Claude (February 1982). "Design Studies of the Vostok-J and Soyuz Spacecraft". Journal of the British Interplanetary Society 35 (2): 92. 
  4. ^ Pike, John. "L-1 Lunar Circumnavigation Mission". Global Security. 
  5. ^ Chariots, ch. 1:6: Priming the Pipeline
  6. ^ a b Chariots, ch. 1-7:The Feasibility Studies
  7. ^ a b Chariots, ch. 1-8:Portents for Apollo
  8. ^ Akens 1971, p. 4.
  9. ^ a b Arthur, George R, "Lunar Spacecraft Designs", Advanced in the Astronautical Sciences, Volume 10, 1963, p. 52.
  10. ^ Chariots, ch. 1-8:The Challenge
  11. ^ Chariots, ch. 2-1:May through December 1961
  12. ^ Chariots, ch. 2-5:Contracting for the Command Module
  13. ^ Benson, Charles D.; William Barnaby Faherty (1978). "4-8". Moonport: A History of Apollo Launch Facilities and Operations. NASA (SP-4204). Retrieved 7 February 2013. 
  14. ^ "The Rendezvous That Was Almost Missed: Lunar Orbit Rendezvous and the Apollo Program". NASA Langley Research Center. December 1992. Retrieved 8 June 2012. 
  15. ^ Chariots, ch. 5-1:Command Modules and Program Changes
  16. ^ Futron Corp. (2003). "China and the Second Space Age". Futron Corporation. Retrieved 6 February 2013. 

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

External links[edit]