page_title: Advanced Gemini
section_title: Big Gemini
hierarchical_section_title: Advanced Gemini / Big Gemini
caption_attribution_description: Big Gemini concept space station supply ship. August, 1969. (NASA)
context_page_description: Advanced Gemini is a number of proposals that would have extended the Gemini program by the addition of various missions, including manned low Earth orbit, circumlunar and lunar landing missions. Gemini was the second manned spaceflight program operated by NASA, and consisted of a two-seat spacecraft capable of maneuvering in orbit, docking with unmanned spacecraft such as Agena Target Vehicles, and allowing the crew to perform tethered extra-vehicular activities.
  A range of applications were considered for Advanced Gemini missions, including military flights, space station crew and logistics delivery, and lunar flights. The Lunar proposals ranged from reusing the docking systems developed for the Agena target vehicle on more powerful upper stages such as the Centaur, which could propel the spacecraft to the Moon, to complete modifications of the Gemini to enable it to land on the Lunar surface. Its applications would have ranged from manned lunar flybys before Apollo was ready, to providing emergency shelters or rescue for stranded Apollo crews, or even replacing the Apollo program.
context_section_description: Big Gemini, or Big G, grew out of a 1963 proposal called Gemini Transport, to develop an enlarged Gemini spacecraft with docking capability, which would take advantage of the increased capacity offered by the Saturn IB and Titan IIIM rockets. It was designed to transport between nine and twelve astronauts into space, and to be able to dock with space stations, in support of Apollo Applications and MOL missions. It would have been launched by a Heavy lift launch vehicle; either a Titan IIIG or Saturn INT-20, the former being intended for use on US Air Force missions and the latter being intended for NASA missions. The Titan IIIM was also considered, which would have launched a smaller version of the spacecraft due to its lower capacity, to resupply MOL space stations later in the program. NASA also proposed several Saturn IB derivatives with solid first stages as alternatives to the INT-20, offering similar payload capacity.
  The shape and mass of the spacecraft would have varied depending on the rocket that was to launch it. The Saturn-launched version had a short, conical cargo module, and a total mass of 47,300 kilograms (104,300 lb) whereas the Titan IIIG-launched version featured a longer, cylindrical module, with a total mass of 59,000 kilograms (130,000 lb). The Titan IIIM version would have been much shorter and lighter, with a mass of 15,600 kilograms (34,400 lb), as that rocket had less payload capacity than the Titan IIIG or Saturn. The IIIG variant would have carried twelve crew, while the others had a maximum capacity of nine. Use of the NASA variant with the Apollo Service Module was also considered.
  Once in orbit, Big G would have docked with space stations using an Apollo docking probe mounted on the rear of the cargo module, which was in turn mounted on the rear of the re-entry module. The re-entry module itself would have been enlarged to accommodate the larger crew, and the modifications made to the spacecraft for the MOL program would have been incorporated, including the hatch in the heat shield, which would have been used to provide access to the cargo module. In the event of a launch failure, the launch escape system developed for the Apollo spacecraft would have been used to propel the re-entry module clear of the rocket.
  Big G would have made landings on land, using a parasail or paraglider to guide it onto a runway or dry lake, such as the one at Edwards Air Force Base. It would have landed using skids derived from the North American X-15.
caption: Big Gemini (Titan IIIG version)
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