Project Gemini

Project Gemini was the second United States human spaceflight program to fly. It came after the first American crewed space program, Project Mercury, and happened while the Apollo program was still getting started. Gemini ran from 1961 to 1966. The Gemini spacecraft carried two astronauts each time they flew, and ten crews with sixteen different astronauts completed missions in low Earth orbit during 1965 and 1966.

The main goal of Gemini was to prepare for sending astronauts to the Moon with Apollo. Gemini helped the United States catch up with the Soviet Union by showing that astronauts could stay in space almost 14 days, practice moving around outside their spacecraft without getting too tired, and learn how to meet and connect with other spacecraft. This meant Apollo could focus on landing on the Moon without needing to figure these things out first.

All Gemini missions lifted off from Launch Complex 19 (LC-19) at Cape Kennedy Air Force Station in Florida. They used a special rocket called the Titan II GLV, which was changed from an intercontinental ballistic missile. Gemini was the first program to use the new Mission Control Center at the Houston Manned Spacecraft Center to guide the flights. The program also used another spacecraft called the Agena target vehicle to help practice meeting and connecting in space.

The astronauts who flew in Gemini came from groups called the "Mercury Seven", "The New Nine", and "The Fourteen". Sadly, three astronauts died in plane crashes while training, including the two meant to fly Gemini 9, so the backup crew took their place. Gemini was strong enough that the United States Air Force thought about using it for another program, but those plans were canceled later.

Pronunciation

The project Gemini was named after a constellation, and people had different ways of saying its name. Some said it like "Jeh'-mih-nee," rhyming with "knee," which was the way NASA's team and astronauts used. This pronunciation was made the official one by NASA in 1965. For example, astronaut Gus Grissom called the spacecraft "Jeh-mih-nee 4" during a spacewalk by Ed White on Gemini 4, and this way of saying it was also used in the film First Man/.

Program origins and objectives

The Apollo program was planned as a way to send three people into space after Project Mercury. In 1961, engineers thought about a program to help bridge the gap between Mercury and Apollo. They called it Mercury Mark II.

After President John F. Kennedy announced the goal of landing humans on the Moon, NASA knew they needed more practice before Apollo. So, they created a new program called Project Gemini, meaning "twins" because it was about two people working together. The main goals of Gemini were to:

• Show that people and equipment could stay in space for longer trips, up to two weeks.
• Practice meeting and joining up with another spacecraft.
• Try moving around outside the spacecraft to do tasks.
• Improve how to land safely back on Earth at a specific spot.

Team

Chamberlin designed the Gemini capsule, which carried a crew of two. He joined NASA along with 25 senior engineers after the cancellation of the Canadian Arrow program and became head of the U.S. Space Task Group's engineering division for Gemini. The prime contractor was McDonnell Aircraft Corporation, which also worked on the Project Mercury capsule.

Astronaut Gus Grissom helped develop and design the Gemini spacecraft. The spacecraft was designed around Grissom’s height, but later had to be changed so more astronauts could fit inside. Grissom focused his efforts on Gemini after realizing he might not fly again in the Mercury program.

The Gemini program was managed by the Manned Spacecraft Center in Houston, Texas, under the Office of Manned Space Flight at NASA Headquarters in Washington, D.C. Dr. George E. Mueller served as acting director of the Gemini program. Guenter Wendt was a McDonnell engineer who supervised launch preparations for both Mercury and Gemini. His team handled the final checks before launch, and he was the last person the astronauts saw before the hatch closed.

Spacecraft

In 1961, NASA chose McDonnell Aircraft to build the Gemini capsule, which was delivered in 1963. The spacecraft was 18 feet 5 inches long and 10 feet wide, with a launch weight between 7,100 and 8,350 pounds.

The Gemini crew capsule was larger than the Project Mercury capsule. It had a special part called the Adapter Module that separated from the main capsule when returning to Earth. This design made it easier to fix parts inside the spacecraft without disturbing everything else.

Gemini was the first spacecraft to have a computer on board to help control the mission. It also had tools like radar and joysticks to help astronauts guide the spacecraft. Astronauts could control the spacecraft’s movement in many directions, which helped them meet up with and connect to other spacecraft.

The original plan was for Gemini to land on solid ground instead of in the water, but this idea was changed. Instead, Gemini used parachutes to land in the ocean, just like Mercury did. The capsule was positioned differently when it landed to protect the heat shield.

Launch vehicle

Main article: Titan II GLV

The Titan II was introduced in 1962 as an important rocket for the U.S. Air Force. It used special fuels that made it easier to prepare for launch and simpler in design. However, these fuels, including nitrogen tetroxide and hydrazine, were very dangerous. The Titan II also faced challenges that needed to be solved before it could carry astronauts safely. This rocket used a special radio guidance system for launches from Cape Kennedy.

Astronauts

Deke Slayton was in charge of choosing the astronauts for the Gemini program. Each mission had a main crew and a backup crew. The backup crew would become the main crew three missions later. Slayton wanted the first missions to be led by astronauts from the Mercury Seven: Alan Shepard, Grissom, Cooper, and Schirra. However, some of these astronauts faced health issues or other problems that kept them from flying during Gemini.

The astronauts had two main roles: Command Pilot and Pilot. Sixteen astronauts flew on 10 Gemini missions:

Crew selection

In 1963, Slayton began assigning crews for the early Gemini missions. However, delays and health issues led to several changes in who would fly and when. Unfortunately, some astronauts passed away in a plane crash and in a fire, which also affected the crew assignments. These changes helped decide who would be part of the early Apollo crews, including those who would later aim to be the first to walk on the Moon.

Missions

In April 1964 and January 1965, two Gemini missions were flown without crews to test systems and the heat shield. These were followed by 10 flights with crews in 1965 and 1966. All were launched by Titan II launch vehicles. Some highlights from the Gemini program included the first crewed Gemini mission, Gemini 3, where astronauts used thrusters to change their orbit. On Gemini 4, Ed White became the first American to make an extravehicular activity (or "spacewalk").

Other important moments included Gemini 5 showing that astronauts could survive in space for eight days, and Gemini 6A achieving the first space rendezvous with Gemini 7. Gemini 8 was the first to space docking with an uncrewed craft. Later missions set new records for how high people could travel in Earth’s orbit.

Rendezvous in orbit is tricky. If a spacecraft speeds up to catch another, it actually moves farther away. The correct way is to drop into a lower orbit to get closer, then match speeds. Special simulators were built to help astronauts practice these moves.

Gemini-Titan launches and serial numbers

Main article: Titan II GLV

The Gemini-Titan II launch vehicle was adapted by NASA from the U.S. Air Force Titan II ICBM. Similar to how the Mercury-Atlas vehicle came from the USAF Atlas missile, these rockets carried special numbers given by the Air Force. These numbers were painted in four places on each rocket. Air Force crews helped prepare and launch these vehicles, and the information learned was useful for both the Air Force and NASA.

Fifteen of these rockets were ordered in 1962, with numbers starting with "62-12XXX". However, only "12XXX" was painted on the rockets. Plans for the last three rockets were canceled in 1964, so they were never built, but they still had numbers assigned to them.

Program cost

Project Gemini cost a lot of money. From 1962 to 1967, it spent about $1.3 billion, which is like $9.31 billion today. In 1969, a report said Gemini cost $1.2834 billion. This included money for the spacecraft, launch vehicles, and support.

Current location of hardware

Spacecraft

• Gemini 1: It broke apart when it came back through the atmosphere.
• Gemini 2: Air Force Space and Missile Museum, Cape Canaveral Air Force Station, Florida
• Gemini III: Grissom Memorial, Spring Mill State Park, Mitchell, Indiana
• Gemini IV: National Air and Space Museum, Washington, D.C.
• Gemini V: Johnson Space Center, NASA, Houston, Texas
• Gemini VI: Stafford Air & Space Museum, Weatherford, Oklahoma
• Gemini VII: National Air and Space Museum, Washington, D.C.
• Gemini VIII: Armstrong Air and Space Museum, Wapakoneta, Ohio
• Gemini IX: Kennedy Space Center, NASA, Merritt Island, Florida
• Gemini X: Kansas Cosmosphere and Space Center, Hutchinson, Kansas
• Gemini XI: California Museum of Science and Industry, Los Angeles, California
• Gemini XII: Adler Planetarium, Chicago, Illinois

Trainers and boilerplates

• Gemini 3A (2411): St. Louis Science Center, St. Louis, Missouri.
• Gemini MOL-B (2411): National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio
• Gemini Mission Simulator (5143): U.S. Space & Rocket Center, Huntsville, Alabama
• Gemini Trainer: Discovery Center, Fresno, California
• Gemini Trainer: Kentucky Science Center, Louisville, Kentucky
• Gemini Water Egress Trainer: Texas Air Museum, Slaton, Texas
• Gemini Trainer: Kalamazoo Air Museum, Kalamazoo, Michigan
• Trainer: Pate Museum of Transportation, Fort Worth, Texas
• GATV (6165): National Air and Space Museum, Washington, D.C. (not on display)
• El Kabong: Kalamazoo Air Museum, Kalamazoo, Michigan
• MSC 312: Private residence, Holden, MA
• MSC 313: Private residence, San Jose, California
• Paresev 1A (Rogallo Test Vehicle): Steven F. Udvar-Hazy Center, Chantilly, Virginia
• TTV-1 (6873) paraglider capsule: Steven F. Udvar-Hazy Center, Chantilly, Virginia
• TTV-2 paraglider capsule: Museum of Scotland, Edinburgh
• Gemini boilerplate: Air Force Space and Missile Museum, Cape Canaveral Space Force Station, Florida
• Gemini boilerplate: Air Force Space and Missile Museum, Cape Canaveral Space Force Station, Florida
• Ingress/Egress Trainer: U.S. Space & Rocket Center, Huntsville, Alabama
• MSC-307: USS Hornet Museum, former NAS Alameda, Alameda, California

Mockups and models

A number of detailed Gemini models and mockups are on display:

• Gemini Model - Intrepid Sea, Air & Space Museum, New York
• Gemini Model - The Discovery Center, Fresno, California
• Gemini Model (built for From the Earth to the Moon)- Evergreen Aviation Museum, McMinnville, Oregon
• Gemini Sit-in Model - KSC Visitors Center, Kennedy Space Center, Florida
• Gemini Model - Science Museum Oklahoma, Oklahoma City, Oklahoma
• Gemini Model (made by McDonnell) - Boeing Prologue Room, St. Louis, Missouri
• Gemini Model (made by McDonnell) - Museum of Science & Industry, Chicago, Illinois
• Gemini Sit-in Model - Neil Armstrong Air and Space Museum, Wapakoneta, Ohio
• Gemini Mockup (winner of the 1967 Revell contest) - Oregon Museum of Science and Industry, Portland, Oregon
• Gemini Model (made by McDonnell) - San Diego Air & Space Museum, San Diego, California
• Gemini Model - Stafford Air & Space Museum, Weatherford, Oklahoma

Proposed extensions and applications

Main article: Advanced Gemini

McDonnell Aircraft, the main company that built the Gemini spacecraft, wanted to keep the program going. They suggested using Gemini for trips around the Moon and even landing on the Moon before the Apollo program was ready. NASA decided against these ideas, choosing to stick with Apollo instead.

There were many ideas for how Gemini could be used, like military missions, delivering supplies to space stations, and even trips to the Moon. Some plans included adding wings or a parasail so the spacecraft could land horizontally instead of splashing down in the ocean.

Main article: Big Gemini

Another idea called Big Gemini was suggested in 1969. It would have been a bigger version of Gemini, able to carry more people and serve many different purposes in space. The design would have allowed the spacecraft to land on the ground instead of the ocean and be reused for future missions. Three different rockets were considered to launch Big Gemini into space.

The Air Force was also interested in using Gemini for military missions, such as watching Earth from space and practicing meeting up with other satellites. This plan was called Blue Gemini. However, Blue Gemini was canceled in 1963, and later the Air Force's space laboratory plans were also canceled, as uncrewed satellites could do the same jobs more cheaply.

In media

The Gemini space missions have been shown in many movies and TV shows. In the 1967 James Bond film You Only Live Twice, two Gemini capsules were called "Jupiter." A 1968 film called Countdown used a smaller Gemini capsule to send an astronaut to the Moon. The first episode of the 1998 HBO series From the Earth to the Moon showed Gemini missions 4, 8, and 12. The 1985 PBS series Spaceflight covered the Gemini program, and the 2018 film First Man included scenes from the Gemini 8 mission. The TV show I Dream of Jeannie often showed footage of Gemini launches. Additionally, a technology standard named “Gemini” uses the year 1965, the first mission’s date, as its special number.