McDonnell Gemini spacecraft
Description
Role:	Orbital spaceflight
Crew:	two; cmd pilot, pilot
Dimensions
Height:	18.6 ft	5.67 m
Diameter:	10 ft	3.05 m
Volume:	90 ft3	2.55 m3
Weights
Reentry module:	4,372 lb	1,983 kg
Retrograde module:	1,303 lb	591 kg
Equipment module:	2,815 lb	1,277 kg
Total:	8,490 lb	3,851 kg
Rocket engines
Retros (solid fuel) x 4:	2,500 lbf ea	11.12 kN
Reentry Control System (N2O4/MMHH) x 16:	25 lbf ea	111 N
OAMS (N2O4/MMHH) x 2:	85 lbf ea	378 N
OAMS (N2O4/MMHH) x 6:	100 lbf ea	445 N
OAMS (N2O4/MMHH) x 8:	25 lbf ea	111 N
Performance
Endurance:	14 days	206 orbits
Apogee:	250 miles	402 km
Perigee:	100 miles	160 km
Spacecraft delta v:	728 f/sec	222 m/sec
Gemini spacecraft diagram
Gemini spacecraft diagram (NASA)
McDonnell Gemini Spacecraft

Gemini was the second human spaceflight program in which the United States of America sent humans into space, between the Mercury program and the Apollo programs, during the years 1963-1966. Its objective was to develop techniques for advanced space travel, notably those necessary for the Apollo program, whose objective was to land men on the Moon. Gemini missions involved extravehicular activity and orbital maneuvers including rendezvous and docking.

Gemini was originally seen as a simple extrapolation of the Mercury program and thus early on was called Mercury Mark II. The final program had little in common with Mercury and was in fact superior to even Apollo in some ways. (See Big Gemini.) This was mainly a result of its late start date, which allowed it to benefit from much that had been learned by that time on the Apollo project (which, despite its later launch dates, was actually begun before Gemini).

The "Gemini" designation comes from the fact that each spacecraft held two men, as "gemini" in Latin means "twins". Gemini is also the name of the third constellation of the Zodiac and its twin stars, Castor and Pollux.

Unlike Mercury, the Gemini capsule could alter its own orbit. It could also dock with other spacecraft--one of which, the Agena Target Vehicle, had its own large rocket engine which was used to perform large orbital changes. Gemini was the first American manned spacecraft to include an onboard computer, the Gemini Guidance Computer , to facilitate management and control of mission maneuvers.

The Gemini program cost $5.4 billion in 1994 dollars. See NASA Budget.

Contents

1 Announcement 2 Team 3 Program objectives 4 Missions 4.1 Unmanned 4.2 Manned 5 Gemini-Titan launches and serial numbers 6 See also: 7 Further reading: 8 External links:

Announcement

The National Aeronautics and Space Administration NASA announced December 7, 1961, a plan to extend the existing manned space flight program by development of a two-man spacecraft. The program was officially designated Gemini on January 3, 1962.

Team

The Gemini program was managed by the Manned Spacecraft Center, Houston, Texas, under direction of the Office of Manned Space Flight, NASA Headquarters, Washington, D.C, Dr. George E. Mueller, Associate Administrator of NASA for Manned Space Flight , served as acting director of the Gemini program. William C. Schneider, Deputy Director of Manned Space Flight for Mission Operations, served as Mission Director on all Gemini flights beginning with Gemini V.

The Manned Spacecraft Center Gemini effort was headed by Dr. Robert R. Gilruth, director of the Center, and Charles W. Matthews, Gemini Program Manager.

Program objectives

The Gemini Program was conceived after it became evident to NASA officials that an intermediate step was required between the Mercury program and the Apollo Program. The major objectives assigned to Gemini were:

• To subject two men and supporting equipment to long-duration flights, a requirement for projected later trips to the moon or deeper space.
• To effect rendezvous and docking with other orbiting vehicles, and to maneuver the docked vehicles in space, using the propulsion system of the target vehicle for such maneuvers.
• To perfect methods of reentry and landing the spacecraft at a pre-selected land-landing point.
• To gain additional information concerning the effects of weightlessness on crew members and to record the physiological reactions of crew members during long duration flights.

Missions

Gemini involved 12 flights, including two unmanned flight tests of the equipment.

Unmanned

• Gemini 1 - First test flight of Gemini
• Gemini 2 - Suborbital flight to test heat shield

Manned

• Gemini III , MOLLY BROWN

March 23, 1965

Virgil "Gus" Grissom, John W. Young

04 hours, 52 minutes 31 seconds

First manned Gemini flight, three orbits.

The only major incident during the orbital phase involved a contraband corned beef sandwich that Young had snuck on board. The crew each took a few bites before the sandwich had to be restowed. The crumbs it released could have wreaked havoc with the craft's electronics, so the crew were reprimanded when they returned to Earth. Other crews were warned not to pull the same type of stunt again.

• Gemini IV

June 03-07, 1965

James A. McDivitt, Edward H. White II

4 days 1 hour 56min 12 seconds

Included first extravehicular activity (EVA) by an American; White's "space walk" was a 22 minute EVA exercise.

• Gemini V

August 21-29, 1965

L. Gordon Cooper, Jr., Charles Conrad, Jr.

7 days 22 hours 55 min 14 seconds

First week-long flight

First use of fuel cells for electrical power; evaluated guidance and navigation system for future rendezvous missions. Completed 120 orbits.

• Gemini VII

December 04-18, 1965

Frank Borman, James A. Lovell, Jr.

13 days, 18 hours, 35 minutes 1 seconds

When the original Gemini VI mission was scrubbed because its Agena target for rendezvous and docking failed, Gemini VII was used for the rendezvous instead. Primary objective was to determine whether humans could live in space for 14 days.

• Gemini VI

December 15-16, 1965

Walter M. Schirra, Jr., Thomas P. Stafford

1 Day 1 hour 51 min 24 seconds

First space rendezvous accomplished with Gemini VII, station-keeping for over five hours at distances from 0.3 to 90 m (1 to 295 ft).

• Gemini VIII

March 16, 1966

Neil A. Armstrong, David R. Scott

10 hours, 41 minutes 26 seconds

Accomplished first docking with another space vehicle, an unmanned Agena stage. A malfunction caused uncontrollable spinning of the craft; the crew undocked and effected the first emergency landing of a manned U.S. space mission.

• Gemini IX

June 03-06, 1966

Thomas P. Stafford, Eugene A. Cernan

3 days, 21 hours

Rescheduled from May to rendezvous and dock with augmented target docking adapter (ATDA) after original Agena target vehicle failed to orbit. ATDA shroud did not completely separate, making docking impossible. Three different types of rendezvous, two hours of EVA, and 44 orbits were completed.

• Gemini X

July 18-21, 1966

John W. Young, Michael Collins

2 days 22 hours 46 min 39 seconds First use of Agena target vehicle's propulsion systems. Spacecraft also rendezvoused with Gemini VIII target vehicle. Collins had 49 minutes of EVA standing in the hatch and 39 minutes of EVA to retrieve experiment from Agena stage. 43 orbits completed.

• Gemini XI

September 12-15, 1966

Charles Conrad, Jr., Richard F. Gordon, Jr.

2 days 23 hours 17 min 8 seconds

Gemini record altitude, 1,189.3 km (739.2 mi) reached using Agena propulsion system after first orbit rendezvous and docking. Gordon made 33-minute EVA and two-hour standup EVA. 44 orbits.

• Gemini XII

November 11-15, 1966

James A. Lovell, Jr., Edwin "Buzz" Aldrin

3 days, 22 hours, 34 minutes 31 seconds Final Gemini flight. Rendezvoused and docked manually with its target Agena and kept station with it during EVA. Aldrin set an EVA record of 5 hours, 30 minutes for one space walk and two stand-up exercises.

Gemini-Titan launches and serial numbers

The Gemini-Titan launch vehicles, like the Mercury-Atlas vehicles before them, were ordered by NASA through the U. S. Air Force. The Titan II's were in reality missiles. The Air Force had a relationship with the missile manufacturers, not NASA. The Gemini-Titan II rockets were assigned U.S. Air Force serial numbers. These serial numbers were painted in four places on each Titan II. On opposite sides, at the bottom of the first stage and on opposite sides, at the bottom of the second stage. U.S. Air Force crews maintained Launch Complex 19 and prepared and launched all of the Gemini-Titan II launch vehicles.

These are the USAF serial numbers assigned to the Gemini-Titan launch vehicles. They were ordered in 1962 so the serial is "62-12XXX", but only "12XXX" is painted on the Titan II:

• 12556 - GLV-1 - Gemini 1
• 12557 - GLV-2 - Gemini 2
• 12558 - GLV-3 - Gemini 3
• 12559 - GLV-4 - Gemini 4
• 12560 - GLV-5 - Gemini 5
• 12561 - GLV-6 - Gemini 6A
• 12562 - GLV-7 - Gemini 7
• 12563 - GLV-8 - Gemini 8
• 12564 - GLV-9 - Gemini 9A
• 12565 - GLV-10 - Gemini 10
• 12566 - GLV-11 - Gemini 11
• 12567 - GLV-12 - Gemini 12
• 12568 - GLV-13 Ordered by NASA 1962, not built, cancelled July 30, 1964
• 12569 - GLV-14 Ordered by NASA 1962, not built, cancelled July 30, 1964
• 12570 - GLV-15 Ordered by NASA 1962, not built, cancelled July 30, 1964

See also:

• National Aeronautics and Space Administration
• Titan (rocket family)
• Titan II rocket
• Big Gemini
• Manned Orbiting Laboratory
• Splashdown

Further reading:

• Gene Kranz, Failure is Not an Option. Factual, from the standpoint of a chief flight controller during the Mercury, Gemini, and Apollo space programs.
• On the Shoulders of Titans: A History of Project Gemini - NASA report (PDF format)
• Project Gemini technology and operations - A chronology - NASA report (PDF fomat)

External links:

• On the Shoulders of Titans: A History of Project Gemini by Barton C. Hacker and James M. Grimwood
• John F. Kennedy Space Center - The Gemini Program
• NASA Project Gemini site
• Space history: Gemini Program space history - Gemini missions spaceflight
• Project Gemini Drawings and Technical Diagrams
• Technical Diagrams and Drawings