Project Gemini was the
second human spaceflight program
of NASA, the
civilian space agency of the United
McDonnell Gemini spacecraft
Gemini spacecraft in
|Retros (solid fuel) x 4:
||2,500 lbf ea
|Reentry Control System
(N2O4/MMHH) x 16:
||25 lbf ea
(N2O4/MMHH) x 2:
|85 lbf ea
(N2O4/MMHH) x 6:
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|Spacecraft delta v:
Gemini spacecraft diagram
Gemini spacecraft diagram
McDonnell Gemini Spacecraft
Project Gemini operated between Projects
, with 10 manned flights occurring in
1965 and 1966. Its objective was to develop techniques for advanced
space travel, notably those necessary for Project Apollo
, whose objective was to land
humans on the Moon
. Gemini missions included
the first American spacewalks
, and new orbital maneuvers
including rendezvous and docking
The Gemini Program was conceived after it became evident to NASA
officials that an intermediate step was required between the
. The major objectives assigned to
- To subject two crewmembers 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
- To accomplish EVA, (Extra Vehicular Activity) or space-walks
outside the protection of the space craft.
Gemini was originally seen as a simple extrapolation of the Mercury
program, and thus early on was called Mercury Mark II
actual program had little in common with Mercury and was superior to even Apollo in some ways
. This was
mainly a result of its late start date, which allowed it to benefit
from much that had been learned during the early stages of the
Apollo project (which, despite its later launch dates, was actually
begun before Gemini).
Its primary difference from Mercury was that the earlier spacecraft
had all systems other than the reentry
situated within the capsule, to which access of nearly
all was through the astronaut's hatchway, while Gemini had many
power, propulsion, and life support
in a detachable module like a huge bowl, akin to the
bifurcation between the Apollo command and service modules; many
components in the capsule itself were reachable each through its
own small access door. The original intention was for Gemini to
land on solid ground instead of at sea, using a paraglider
rather than a parachute, and for the
crew to be seated upright controlling the forward motion of the
craft before its landing. To facilitate this, the parachute cord
did not attach just to the nose of the craft; there was an
additional attachment point for balance near the heat shield. This
cord was covered by a strip of metal between the doors. Early
short-duration missions had their electrical power supplied by
batteries; later endurance missions had the first fuel cells
in manned spacecraft.
The "Gemini" designation comes from the fact that each spacecraft
held two people, as "gemini" in Latin means "twins". Gemini
is also the name of the third
constellation of the Zodiac
and its twin
Unlike Mercury, which could only change its orientation in space
, the Gemini
spacecraft could alter its orbit
. It could
also dock with the Agena Target
, which had its own large rocket engine and 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. It was also unlike
other NASA craft in that it used ejection
, in-flight radar
and an artificial horizon
- devices borrowed
from the aviation industry. Using ejection seats to push astronauts
to safety was first employed by the Soviet Union in the Vostok
craft manned by cosmonaut Yuri Gagarin
The Gemini program cost $5.4
Gemini was designed by a Canadian,
, formerly the chief
on the Avro Arrow
fighter interceptor program with Avro
Canada. Chamberlin joined NASA along with 25 senior Avro engineers
after cancellation of the Arrow program, and became head of the
U.S. Space Task Group’s engineering division in charge of Gemini.
The main contractor was McDonnell, which had lost out on main
contracts for the Apollo Project. McDonnell sought to extend the
program by proposing a Gemini craft which could be used to fly a
mission and even achieve a
manned lunar landing earlier and at less cost than Apollo, but
these proposals were rejected.
In addition, astronaut Gus Grissom
was heavily involved in the
development and design of the Gemini
. He writes in his posthumous 1968 book
that the realization of Project Mercury
's end and the unlikelihood
of his having another flight in that program prompted him to focus
all of his efforts on the upcoming Gemini Program.
program was managed by the Manned Spacecraft Center, Houston,
Texas, under direction of the Office of Manned Space Flight,
Headquarters, Washington, D.C, Dr. George E.
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 VI.
A cutaway of the Project Gemini
The United States Air Force had an interest in the system, and
decided to use its own modification of the spacecraft as the crew
vehicle for the Manned Orbital
. To this end, one of the unmanned Gemini spacecraft
was refurbished and flown again atop a mockup of the MOL, sent into
space by a Titan III
-M. This was the first
time a spacecraft went into space twice.
The USAF also had the notion of adapting the Gemini spacecraft for
military applications, such as crude observation of the ground (no
specialized reconnaissance camera could be carried) and practicing
making rendezvous with suspicious satellites. This project was
called Blue Gemini
. The US Air Force did
not like the fact that Gemini would have to be recovered by the US
Navy, so they intended for Blue Gemini eventually to use the
paraglider and land on three skids, something from the original
design of Gemini.
At first some within NASA welcomed sharing of the cost with the
USAF, but it was later agreed that NASA was better off operating
Project Gemini by itself. MOL was cancelled in 1968 and Blue Gemini
too was cancelled without any use by military astronauts.
Gemini derivatives were proposed, including Big Gemini, Gemini LOR,
Gemini Lunar Lander, Gemini-Centaur, Gemini Ferry, Gemini Transport, Gemini - Saturn I, Gemini - Saturn IB, Gemini - Saturn V, Gemini Pecan, Extended Mission Gemini, Gemini - Double Transtage,
Inspector, Gemini Lunar Surface
Rescue Spacecraft, Gemini
Observatory, Gemini Para
glider, Rescue Gemini, Winged Gemini, Gemini
LORV and Gemini Lunar Surface
In 2005, NASA Administrator Michael
announced that the new Orion spacecraft
, an Apollo-derived
spacecraft, would use the Gemini/Agena chasedown and docking
technique if NASA starts sending crews back to the Moon by 2020.
The Orion, which would replace the Space
(which currently lands on a conventional runway similar
to the early Gemini and Blue Gemini
paraglider/skids technique), was originally designed to land on
solid ground using deployable airbags or a Soyuz
-style retrorocket system, but it is currently
envisioned to be recovered in the ocean.
In addition, NASA may opt to replace the proposed launch escape system
with the so-called
Max Launch Abort System
(MLAS) which would work in the same fashion as the Mercury
and Apollo escape towers, but
incorporate the rockets into the launch shroud itself, eliminating
the tower altogether and allowing the Orion spacecraft to resemble
the towerless Gemini-Titan launch system.
The following astronauts
flew on the 10
manned Gemini missions:
as head of the Astronaut
Office had the main role in the choice of crews for the Gemini
program. With Gemini it became a procedure that each flight had a
primary crew and backup crew and that the backup crew would rotate
to primary crew status three flights later. Slayton also intended
for first choice of mission commands to be given to the four
remaining active astronauts of the Mercury
, Alan Shepard
, Gus Grissom
and Wally Schirra
. John Glenn
had retired from NASA in January 1964
and Scott Carpenter
, who was blamed
by some in NASA management for the problematic reentry of
, was on leave to
participate in the Navy's SEALAB
project and was grounded
from flight in July 1964. Slayton himself continued to be grounded
due to a heart problem.
In late 1963, Slayton selected Alan Shepard and Thomas Stafford
for Gemini 3, James
McDivitt and Ed White for Gemini 4, and Wally Schirra and John
Young for Gemini 5 (the first Agena rendezvous mission). Gemini 3
was backed up by Gus Grissom and Frank Borman, who were also slated
for Gemini 6
, the first long-duration
mission. Finally Pete Conrad and James Lovell were assigned as the
backup for Gemini 4
Delays in the production of the Agena Target Vehicle caused the
first rearrangement of the crew rotation. The Schirra and Young
mission was bumped to Gemini 6 and they now were the backup crew
for Shepard and Stafford. Grissom and Borman now had their
long-duration mission assigned to Gemini 5.
The second rearrangement occurred when Alan Shepard developed
Meniere's disease, an inner ear problem. Gus Grissom was moved to
command Gemini 3. Slayton felt that Young was a better personality
match with Grissom and switched Stafford and Young. Finally Slayton
tapped Gordon Cooper to command the long-duration Gemini 5. Again
for reasons of compatibility he moved Pete Conrad from being the
backup commander of Gemini 4 to be the pilot of Gemini 5, and Frank
Borman to the backup command of Gemini 4. Finally he assigned Neil
Armstrong and Elliot See
to be the backup
crew for Gemini 5.
The third rearrangement of crew assignment occurred when Deke
Slayton felt that Elliot See wasn't up to the physical demands of
EVA on Gemini 8. He reassigned Elliot See to be the prime commander
of Gemini 9 and put Dave Scott as pilot of Gemini 8 and Charles
Bassett as the pilot of Gemini 9.
The fourth and final rearrangement of the Gemini crew assignment
occurred after the deaths of Elliot See and Charles Bassett in a
plane crash in St. Louis. The backup crew of Tom Stafford and
Eugene Cernan was moved up to become the new prime crew of Gemini
9. James Lovell and Edwin "Buzz" Aldrin were moved from being the
backup crew of Gemini 10 to be the backup crew of Gemini 9. This
cleared the way through the crew rotation for Lovell and Aldrin to
become the prime crew of Gemini 12. Along with the deaths of
Grissom, White, and Chaffee in the fire of Apollo 1, this
rearrangement is what finally determined the makeup of the early
Apollo crews. These events were decisive in determining who would
be in position to first walk on the Moon.
In his autobiography Deke!
Slayton relates that he would
probably have replaced Aldrin with Eugene Cernan, the backup pilot
for Gemini 12, if the second flight of the AMU had flown on Gemini
12. Cernan makes a similar claim in his autobiography.
There were 12 Gemini flights, including two unmanned flight tests.
All were launched by Titan II
||LV Serial No
||8 April-12, 1964
||First test flight of Gemini
||19 January 1965
||00d 00h 18m 16s
||Suborbital flight to
test heat shield
||LV Serial No
||23 March 1965
||00d 04h 52m 31s
|First manned Gemini flight, three orbits.
||3-7 June, 1965
||04d 01h 56m 12s
|Included first extravehicular activity (EVA) by an
American; White's "space walk" was a 22 minute EVA exercise.
||21-29 August, 1965
||07d 22h 55m 14s
|First week-long flight; first use of fuel cells for
electrical power; evaluated guidance and navigation system for
future rendezvous missions. Completed 120 orbits.
||4-18 December, 1965
||13d 18h 35m 01s
|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.
||15-16 December, 1965
||01d 01h 51m 24s
|First space rendezvous accomplished with Gemini
VII, station-keeping for over five hours at distances from 0.3 to
90 m (1 to 300 ft).
||16-17 March, 1966
||00d 10h 41m 26s
|Accomplished first docking with another space
vehicle, an unmanned Agena stage. While docked, a Gemini spacecraft
thruster malfunction caused near-fatal tumbling of the craft,
which, after undocking, Armstrong was able to overcome; the crew
effected the first emergency landing of a manned U.S. space
||3-6 June, 1966
||03d 00h 21m 50s
|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.
||18-21 July, 1966
||02d 22h 46m 39s
|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
||12-15 September, 1966
||02d 23h 17m 08s
|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
||11-15 November, 1966
||03d 22h 34m 31s
|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, and demonstrated improvements to
previous EVA problems.
Gemini-Titan launches and serial numbers
vehicles, like the Mercury-Atlas
vehicles before them, were ordered by NASA through the U. S. Air
Force and were in reality missiles. The Gemini-Titan II rockets
were assigned U.S. Air Force serial numbers, which were painted in
four places on each Titan II (on opposite sides on each of the
first and second stages). U.S. Air Force crews maintained Launch
Complex 19 and prepared and launched all of the Gemini-Titan II
USAF serial number location on Titan II.
The USAF serial numbers assigned to the Gemini-Titan launch
vehicles are given in the tables above. Fifteen Titan IIs were
ordered in 1962 so the serial is "62-12XXX", but only "12XXX" is
painted on the Titan II. The order for the last three of the
fifteen launch vehicles was cancelled on 30 July 1964, and they
were never built. Serial numbers were, however, assigned to them
- GLV-13; 12569
All Gemini Launches from GT-1 through
Current location of hardware
Gemini 1 - Destroyed
Gemini 2 -
Air Force Space &
Missile Museum, Cape Canaveral Air Force
- Grissom Memorial, Spring Mill State
Park, Mitchell, Ind.
- National Air and Space
Museum, Washington D.C.
Gemini V -
Johnson Space Center, NASA, Houston, Texas
- Oklahoma History Center, Oklahoma City, Okla.
- Steven F. Udvar-Hazy
Center, Chantilly, Va.
Gemini VIII - Armstrong
Air and Space Museum
, Wapakoneta, Ohio
- Kennedy Space Center, NASA, Cape Canaveral, Fla.
- Kansas Cosmosphere and
Space Center, Hutchinson, Kan.
Gemini XI - California Museum of
Science and Industry
, Los Angeles, Calif.
XII - Adler Planetarium, Chicago, Ill.
- St. Louis Science Center, St. Louis, Mo.
MOL-B - National Museum
of the United States Air Force,
Wright-Patterson Air Force Base, Dayton, Ohio
Trainer - U.S. Space &
Rocket Center, Huntsville, Ala.
Trainer - Goddard Space Flight
Center (Visitor Center), NASA, Greenbelt, Md.
Gemini Trainer - Louisville
, Louisville, Ken.
6165 - National Air and Space Museum, Washington D.C. (not on
El Kabong - Kalamazoo Air Museum, Kalamazoo, Mich.
Gemini Trainer - Kalamazoo Air Museum, Kalamazoo, Mich.
Royal Museum, Edinburgh,
Trainer - Pate Museum of Transportation, Fort Worth, Texas
MSC 313 - Private residence, San Jose, Calif.
Test Vehicle - White Sands Space
Harbor, White Sands, N.
TTV-1 - Stephen F. Udvar-Hazy Center, Chantilly, Va.
unnamed - U.S. Air Force Space Museum, Cape Canaveral Air Force
unnamed - U.S. Air Force Space Museum, Cape Canaveral Air Force
Gemini Trainer - BDL
Aerospace and Flight Museum
, NAS Whidbey Island, Oak Harbor,
U.S. Astronaut Hall
of Fame, Titusville, Fla.
USS Hornet Museum, Alameda, Calif.
- Astronaut's Gemini
- Francis French and Colin Burgess, In the Shadow of the Moon:
A Challenging Journey to Tranquility, 1965-1969. History of
the entire Gemini program.
- Gene Kranz, Failure is Not an
Option. Factual, from the standpoint of a chief flight
controller during the Mercury,
Gemini, and Apollo space programs.
- David M. Harland, How NASA Learned to Fly in Space: An
Exciting Account of the Gemini Missions, Apogee Books, 2004,
- David J. Shayler, Gemini, Springer-Verlag Telos, 2001,
- On the Shoulders of Titans: A History of Project
Gemini - (NASA report SP-4203) (PDF format)
- Project Gemini - A Chronology (NASA report SP-4002)
- Gemini Midprogram Conference - Including Experiment
Results (NASA report SP-121) - Manned Spacecraft Center - Houston,
Texas, February 23-25, 1966
- Gemini Summary Conference (NASA report SP-138) - Manned
Spacecraft Center - Houston, Texas, February 1-2, 1967