Gemini Program

Gemini 6 seen from Gemini 7.

The Gemini Program was the second manned space program in the United States, developed in the early 1960s as part of the space race with the Soviet Union. The project began in 1965 after the US space agency NASA ended its first space flight program: the pioneering Mercury program, which had succeeded in placing the first American astronauts in Earth orbit.

The Gemini program, unlike its predecessor and its subsequent continuation with the Apollo Program, did not produce as much euphoria in public opinion despite the fact that the developments achieved in this project would be of vital importance for the development of future missions Apollo and the goal of taking the human being to the Moon.

Scope of the program

The Gemini program was officially announced to the public on January 3, 1962 when the Apollo program was already in an advanced stage of development. His overall goal was to gain experience in space exploration so that he could put humans on the moon before the end of the decade, as President John Fitzgerald Kennedy had announced in his famous speech at Rice University in September 1962. specific objectives practice maneuvers and know the resistance capacity of the astronauts, as well as the ships. It was also necessary to test docking and alignment techniques as well as perform multiple extravehicular exercises (EVA) or "space walks".

Gemini Insignia 4.

The main purpose of the Gemini program was to demonstrate the space rendezvous and docking capabilities that would be used during the Apollo missions when the lunar module separated from the command module in orbit around the Moon, and it would later rejoin the spacecraft again after the astronauts left the lunar surface. Another of the objectives of the Gemini missions was to extend the stay of astronauts in space up to two weeks. This is even more than the Apollo missions required.

During the Gemini missions, spaceflight became routine with 10 liftoffs from the launch pads located at Cape Canaveral, Florida in less than 20 months. During this program, the Space Flight Center (named the Lyndon B. Johnson Space Center since 1973) outside Houston, Texas would act as Mission Control.

Flight operations were efficient and fast due to the short flight windows (the proper time for a launch), which in the case of the Gemini XI window lasted only 2 seconds, the time set for a successful encounter with target ships located in orbit.

Ship Features

The Gemini spacecraft was an improved version of the Mercury and had originally received the name Mercury Mark II. The improvements came in both size and control capabilities. The Gemini had a weight of more than 3,628.72 kilograms, twice that of the Mercury. But on the other hand, despite having a 50% increase in cabin space, it had to be occupied by two astronauts instead of one as in the Mercury missions. Another of the differences of the Gemini spacecraft is that they had ejection seats to replace the Mercury rescue tower, they also had more storage space for long-duration missions, which required fuel cells instead of batteries for generation. of electric power.

Unlike the Mercury, which could only change its orientation in space, the Gemini had to use orbital maneuvering capabilities to rendezvous with another ship. The Gemini had to move forwards, backwards, change orientation and even orbit. Due to the complexity of the rendezvous maneuvers, the spacecraft required the presence of two astronauts and the use of the first on-board computers to perform complicated calculations that would help establish a successful rendezvous.

The ships used Titan II launch vehicles. The rendezvous target at an advanced stage was an unmanned Agena, which was launched ahead of the Gemini. After rejoining its target ship in orbit, the Gemini's nose was attached to a docking collar on the Agena.

To avoid delays in Gemini flights, the ships were easy to maintain and had subsystems that could be replaced. An adapter module attached to the rear of the capsule (which was ejected prior to reentry) contained oxygen, fuel, and other consumables.

Gemini Missions

Official name	Nave	Release date	Launch vehicle	Triple	Objective(s) and data of interest	Outcome	Insignia	Duration
Gemini 1	Gemini 1	8 April 1964	Titan II	Not tripulated	Test mission	Successful	-	-
Gemini 2	Gemini 2	19 January 1965	Titan II	Not tripulated	Suborbital flight to test the reentry heat shield	Successful	-	-
Gemini 3	Gemini 3	23 March 1965	Titan II	Virgil I. Grissom, John W. Young	Gemini first manned flight	Successful		4 hours, 52 minutes, 31 seconds
Gemini 4	Gemini 4	3 June 1965	Titan II	James McDivitt, Edward White	First U.S. Space Walk, conducted by White, lasted 22 minutes	Successful		4 days, 1 hour, 56 minutes, 12 seconds
Gemini 5	Gemini 5	21 August 1965	Titan II	Gordon Cooper, Charles Conrad	Coupling maneuvers. First use of fuel cells to obtain electricity	Successful		7 days, 22 hours, 55 minutes, 14 seconds
Gemini 7	Gemini 7	4 December 1965	Titan II	Frank Borman, James A. Lovell	First approach between two crewed ships. Use as an alignment target for Gemini VI. Ballistic missile tracking from orbit with infrared instruments. Spacecraft duration	Successful.		13 days, 18 hours, 3 minutes, 1 second
Gemini 6A	Gemini 6A	15 December 1965	Titan II	Walter Schirra, Thomas Stafford	First alignment between two manned special ships, with Gemini VII	Successful		1 day, 1 hour, 51 minutes, 24 seconds
Gemini 8	Gemini 8	16 March 1966	Titan II	Neil Armstrong, David Scott	First coupling with another ship, with Agena, unmanned ship. Maniobras, and space walk. First emergency landing of a manned American ship	Partially		10 hours, 41 minutes, 26 seconds.
Gemini 9A	Gemini 9A	3 June 1966	Titan II	Thomas Stafford, Eugene A. Cernan	Connection with Agena stage, maneuvers, and space walk. Three different types of alignment. Intento de abortado por problemas con el vehículo de destino, al presentado problemas con el Adaptador Increaseado de Acoplamiento (ATDA) (althose astronauts of the Stafford and Carnan mission nicknamed "cocodrile angry")	Partially		3 days, 2 hours
Gemini 10	Gemini 10	18 July 1966	Titan II	John W. Young, Michael Collins	Connection with Agena stage, maneuvers, and space walk. First use of Agena vehicle propulsion systems. Vehicle alignment for Gemini VIII. Walk for 49 minutes from the hatch	Successful		2 days, 22 hours, 46 minutes, 39 seconds
Gemini 11	Gemini 11	12 September 1966	Titan II	Charles Conrad, Richard Gordon	Connection with Agena stage, maneuvers, and space walk. Gemini record height of 1,189.3 km, achieved using the Agena propulsion system after alignment and coupling	Successful		2 days, 23 hours, 17 minutes, 8 seconds
Gemini 12	Gemini 12	11 November 1966	Titan II	James A. Lovell, Edwin Aldrin	Connection with Agena stage, maneuvers, and space walk. Gemini's last flight. 5-hour space walk arrangement with 30 minutes	Successful		3 days, 22 hours, 34 minutes, 31 seconds

Quest Legacy

Gemini 6A sighting Gemini 7, 1965 (NASA).

The significance of the Gemini missions was that they gave American astronauts the opportunity to learn about working and sleeping in space in uncomfortable conditions. It was also during these missions that NASA astronauts began their first spacewalks, the first being by an American astronaut by Ed White during the Gemini IV mission.

Towards the end of the Gemini missions, rendezvous and docking operations were already routine and by then, it had been confirmed that astronauts' lives in space could be carried out without major inconveniences.

Another of the contributions of the Gemini program was the number of scientific experiments carried out in space about the conditions of the space environment and the photogeography of the Earth. The last mission was the Gemini XII launched on November 11, 1966 and completed on the 15th of the same month with astronauts James A. Lovell, Jr. and Edwin E. Buzz Aldrin.

In total, nearly 1,000 hours of spaceflight were completed.

Other projects

Gemini Saturn I

In the spring of 1965 , after the cancellation of the flights of the Apollo program using the Saturn I rocket, the use of this launcher to send a Gemini spacecraft around the Moon was studied. The mission would have taken place to fill the gap between the end of the Gemini flights and the beginning of the Apollo flights with the Saturn IB rocket or in the event that the Apollo missions suffered a setback and there was a risk that the Soviets would get ahead in the moon race. To carry out the lunar flight, an Agena or Centaur stage would have been added to the Saturn I. Finally, the idea was discarded given the interests of Wernher von Braun and other promoters of the Apollo program so that efforts would not be diverted to other projects. On June 8 of that year, NASA published instructions so that any study on circumlunar flights related to the Gemini spacecraft was limited to internal studies, prohibiting the establishment of contracts for studies by external companies.

Gemini Saturn IB

The same circumlunar flight scheme with a Gemini spacecraft was also proposed to study the Sea of Tranquility before the Apollo moon landings, but using a Saturn IB rocket and a Centaur upper stage. The scientific equipment would consist of a set of cameras located in the front of the ship. The idea was also scrapped so as not to divert efforts from the Apollo program.

Gemini Saturn V

In addition to circumlunar flight, a version of Gemini was proposed to orbit the Moon using a Saturn V and explore in more detail possible landing sites for Apollo missions. An Agena stage would be used for injection into lunar orbit and return to Earth. The mission profile would involve a 68-hour flight from low Earth orbit to lunar orbit, and another 68 hours back, with a 24-hour period of lunar exploration from an 18x144 km orbit using cameras installed on the front of the ship. The idea was also scrapped so as not to divert efforts from the Apollo program.

Gemini LORV

The LORV concept (Lunar Orbit Rescue Vehicle) was studied as a means to carry out a hypothetical rescue of an Apollo mission that had been immobilized in lunar orbit. The rescue Gemini spacecraft, which would be a version with an enlarged reentry module, would have been launched by a Saturn V and would enter lunar orbit to rendezvous with the disabled Apollo spacecraft, whose crew members would spacewalk to the Gemini spacecraft.. The Gemini spacecraft would then depart back to Earth. The concept was ultimately rejected in favor of the more flexible lunar surface rescue scheme.

Additional bibliography

• “Suddenly Tomorrow Came....”: A History of the Johnson Space Centerof Henry C. Dethloff (NASA SP-4307, 1993).
• Project Gemini Technology and Operations: A ChronologyJames M. Grimwood, Barton C. Hacker and Peter J. Vorzimmer (NASA SP-4002, 1969).
• On Shoulders of Titans: A History of Project GeminiBarton C. Hacker and James M. Grimwood (NASA SP-4203, 1977).
• The Human Factor: Biomedicine in the Manned Space Program to 1980John A. Pitts (NASA SP-4213, 1985).
• Carrying the Fire: An Astronaut Journeysby Michael Collins (Farrar, Straus & Giroux, 1974).