This page no longer updated from 31 October 2001. Latest version can be found at Big Gemini

Big Gemini Mockup
Big Gemini Mockup
Mockup of the Big Gemini reentry module on display at the McDonnell plant, St Louis, in 1967. The large windows allowed viewing of the interior of the mockup and were not going to be part of the flight version! By simply adding a passenger compartment behind the basic Gemini B, McDonnell produced a ballistic reentry vehicle with the same total mass and base diameter as the Apollo Command Module, but over twice the cargo capacity.

Credit: McDonnell Douglas. 62,612 bytes. 484 x 375 pixels.

Manufacturer's Designation: McDonnell-Douglas. Class: Manned. Type: Spacecraft. Nation: USA. Manufacturer: McDonnell-Douglas.

By the end of 1966 NASA's Gemini program was nearing its conclusion and the design phase of the USAF Manned Orbiting Laboratory (MOL) project was nearly finished. McDonnell-Douglas had a large manned spacecraft engineering team, built up over eight years on the Mercury, Gemini, and MOL programs that was facing dissolution. At the same time both USAF and NASA had funded space station projects. The USAF's MOL and the NASA's Apollo Applications Program Orbital Workshop (later Skylab) were to fly in 1969-1974. Both USAF and NASA were planning even larger follow-on stations - the USAF LORL and NASA MORL.

Big Gemini ConfigsBig Gemini Configs - Compared are the Big Gemini configurations planned for use with the Titan 3G for the Air Force (180 inch diameter base) and for use with Saturn launch vehicles for NASA (260 inch diameter base). A shorter version of the Titan 3G version could be used with the Titan 3M.

Credit: McDonnell Douglas. 29,177 bytes. 486 x 360 pixels.

Big Gemini ('Big G') was proposed by McDonnell Douglas to the US Air Force and NASA in 1967 as a ballistic manned orbital logistics spacecraft to provide economical resupply of these military and civilian space stations. The capability of existing spacecraft (Apollo CSM, Gemini) for such missions was severely limited. In the 1970-1980 period, it appeared that at least a dozen launches would be required for logistics purposes for the Apollo Applications Program alone. MOL and the AAP workshop would require 3 to 6 flights a year, each flight delivering a crew of two or three, with 1 to 7 tonnes of cargo being sent up and up to 0.6 cubic meters of cargo being returned. Planned late 1970's stations would have crews of 6 to 24, requiring a resupply craft that could deliver up to 12 passengers and 12 tonnes of payload 6 to 14 times a year, returning up to 7 cubic meters of cargo each time. Big G could provide such a capability by 1971, using Gemini technology applied to Gemini and Apollo hardware, with minimum interference to the higher priority Apollo lunar landing program.

Big Gemini LandingBig Gemini Landing - Big Gemini would land on dry lake beds or airstrips on skids, as were used on the X-15 and were planned for the X-20 and basic Gemini. A parasail would allow the pilot to maneuver to a pinpoint landing.

Credit: McDonnell Douglas. 55,777 bytes. 543 x 376 pixels.

McDonnell Douglas conceded that the initial flights to Orbital Workshop 1 (then planned for 1970) would have to be supported by the Apollo CSM. However Big G could be available in 1971 to provide improved crew and cargo versatility for Orbital Workshop 2 and USAF MOL resupply.

Big G would consist of the following modules:

Big Gemini ModelBig Gemini Model - Cutaway model of the Big Gemini reentry module. This version would accomodate two crew and six passengers; versions for NASA with ejections seats would accomodate two crew and four passengers plus return cargo.

Credit: McDonnell Douglas. 23,241 bytes. 505 x 295 pixels.

It was possible to transfer crew and cargo from Big-G to the space station without extra-vehicular activity. A pressurised tunnel led from the passenger compartment to the cargo area, and another tunnel to the docking probe.

Big G used the "packaged return capability" of the Gemini-B. This included "sealed-until-needed" oxygen supply, RCS system, and retrograde and separation motors. These features, compared to Apollo, improved crew safety by assuring the spacecraft could endure extended in-orbit quiescent storage while docked to the space station.

As another alternative (obviously not favoured by McDonnell Douglas) the Big G re-entry capsule could be used with an Apollo Service Module and the Apollo Applications Program Multi-Mission Module (a palletised cargo carrier mounted, like the Lunar Module, behind the SM, with which Big G would have to dock and extract from the spent booster).

Big Gemini /Titan 3MBig Gemini /Titan 3M - Minimum Air Force version of Big Gemini, launched by a Titan 3M for advanced Manned Orbiting Laboratory (MOL) resupply. This version had a minimal cargo module capability. Total mass was 15,600 kg, and it could deliver 9 crew and 2,500 kg of supplies to a 480 km, 50 degree inclination orbit.

Credit: McDonnell Douglas. 32,618 bytes. 409 x 313 pixels.

Total mass of the Big G would depend on the launch vehicle. The Titan 3M version would total 15,600 kg, delivering 9 crew and 2,500 kg of supplies to MOL in a 480 km, 50 degree inclination orbit. The NASA INT-20 version weighed 47,300 kg and could deliver 9 crew and 27,300 kg of payload to the same orbit. The Titan 3G configuration would have an orbital insertion mass of 59,000 kg in a 28.5 degree, 150 x 220 km orbit.

McDonnell's sales pitch was summarised as follows:

Big G was not to be. Even at the time the concept was originated both NASA and USAF manned space projects were being cut back. Within 18 months, MOL would be cancelled, and AAP would be limited to using only spacecraft and boosters surplus to the moon landing program. Soon thereafter the shuttle became the only funded space project for the 1970's, and all space station work was abandoned. The Gemini spacecraft - and the American push to rapidly exploit the cosmos - were dead.

Big Gemini EvolutionBig Gemini Evolution - Chart showing how the Big Gemini could be derived from existing hardware. Use of the basic reentry module with a range of propulsion and cargo modules was possible. A further evolutionary development would lead to the 'Advance Logistic Spacecraft' of the late 1970's (eventually the Space Shuttle).

Credit: McDonnell Douglas. 29,986 bytes. 493 x 373 pixels.


Craft.Crew Size: 9. Total Length: 11.5 m. Maximum Diameter: 4.3 m. Total Habitable Volume: 18.70 m3. Total Mass: 15,590 kg. Total Payload: 2,500 kg.

Big Gemini Chronology

Big Gemini / OWSBig Gemini / OWS - Use of Big Gemini as a more cost-effective manned logistics vehicle for use with the Apollo Applications Orbital Workshop (eventually Skylab).

Credit: McDonnell Douglas. 20,211 bytes. 468 x 325 pixels.

21 August 1969 McDonnell Douglas Corporation, under contract to MSC, submitted an eight-volume final report on a "Big G" study. Program: Apollo X.

Three features of the McDonnell Douglas 'Big G' study, performed under contract to MSC, are shown here. For additional information on the proposed system, see the 21 August 1969 entry. Graphics supplied by McDonnell Douglas. The study was performed to generate a preliminary definition of a logistic spacecraft derived from Gemini that would be used to resupply an orbiting space station. Land-landing at a preselected site and refurbishment and reuse were design requirements. Two baseline spacecraft were defined: a nine-man minimum modification version of the Gemini B called Min-Mod Big G and a 12-man advanced concept, having the same exterior geometry but with new, state-of-the-art subsystems, called Advanced Big G. Three launch vehicles-Saturn IB, Titan IIIM, and S-IC/S- IVB-were investigated for use with the spacecraft. The Saturn IB was discarded late in the study. The spacecraft consisted of a crew module designed by extending the Gemini B exterior cone to a 419-cm-diameter heat shield and a cargo propulsion module. Recovery of the crew module would be effected by means of a gliding parachute (parawing). The parametric analyses and point design of the parawing were accomplished by Northrop- Ventura Company under a subcontract, and the contents of their final report were incorporated into the document. The landing attenuation of the spacecraft would be accomplished by a skid landing gear extended from the bottom of the crew module, allowing the crew to land in an upright position. The propulsion functions of transfer, rendezvous, attitude control, and retrograde would be performed by a single liquid-propellant system, and launch escape would be provided by a large Apollo-type escape tower. In addition to the design analyses, operational support analyses and a program development plan were prepared. The summary report acknowledged the cooperation of NASA Centers and companies that provided technical assistance during the study. Principal contributors were MSC, MSFC, KSC, AC Electronics Division of General Motors Corporation, Bell Aerosystems Company, Collins Radio Company, IBM's Federal Systems Division, Kollsman Instrument Corporation, Amecom Division of Litton Systems, Inc., The Marquardt Corporation, Denver Division of Martin Marietta Corporation, Government Electronics Division of Motorola Corporation, Rocketdyne Division of North American Rockwell Corporation, Space Craft, Inc., Science and Technology Division of TRW Systems Group, and Hamilton Standard System Center of United Aircraft Corporation.

Big Gemini NASABig Gemini NASA - Comparison of potential NASA configurations for Big Gemini. The preferred, top configuration uses all new hardware. The middle ALSS configuration uses a logistics module developed for the Apollo Orbital Workshop program. The bottom configuration uses the Big Gemini reentry capsule with an Apollo Service Module and Apollo Applications Multi-Mission Module.

Credit: McDonnell Douglas. 15,327 bytes. 376 x 283 pixels.


Big Gemini NASABig Gemini NASA - Larger version of comparison of potential NASA configurations for Big Gemini. The preferred, top configuration uses all new hardware. The middle ALSS configuration uses a logistics module developed for the Apollo Orbital Workshop program. The bottom configuration uses the Big Gemini reentry capsule with an Apollo Service Module and Apollo Applications Multi-Mission Module.

Credit: McDonnell Douglas. 26,507 bytes. 561 x 423 pixels.

Big Gemini BriefingBig Gemini Briefing - Cover page of Big Gemini briefing to NASA, Dec 20 1967. Big Gemini is shown returning its crew of ten to a runway landing beneath its Rogallo wing paraglider.

Credit: McDonnell Douglas. 26,736 bytes. 458 x 380 pixels.

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Last update 12 March 2001.
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© Mark Wade, 2001 .