If you have read the book The Right Stuff or watched the movie with the same name, you may know a thing or two about the Mercury program—which was NASA’s first human spaceflight program. And of course, many are familiar with the Apollo program, which famously put the first human on the Moon. However, there would be no Apollo program without the Gemini program, which took place in between the Mercury and Apollo programs from 1964 to 1965.  

Whereas Mercury focused on getting people up into space, Gemini worked toward keeping them up there for an extended period of time—in preparation for Apollo lunar trips of one to two weeks—and practicing the maneuvers and techniques need to carry out a landing. The Gemini program sent two-astronaut spacecraft into Earth orbit. The missions helped NASA understand and master the challenges of spacewalking, rendezvous and docking, and long-duration spaceflight. Explore some of the key accomplishments of the Gemini program below. 

The Launch Vehicle and Spacecraft 

To launch Mercury and Gemini spacecraft, NASA used ballistic missiles designed to carry nuclear warheads. For the Apollo program, huge Saturn launch vehicles were specially designed to carry the much larger lunar spacecraft. 

Gemini Titan Launch
The Gemini Titan II at liftoff in 1964. U.S. Air Force Titan IIs boosted 10 two-astronaut Gemini spacecraft into orbit. Image courtesy of NASA.

 

The Gemini spacecraft began as the Mercury Mark II, an enlarged capsule made by McDonnell Aircraft in St. Louis. As contractor for the Mercury spacecraft, the company had experience vital to Gemini’s success. 

 

Gemini VII Capsule
The black Gemini reentry vehicle looked like an enlarged Mercury capsule. Attached to its white adapter module, it was even larger. The adapter module carried the oxygen, water, electrical power, propellants, and thrusters needed for multiday missions and orbital maneuvers. Image courtesy of the Smithsonian Institution. 

Frank Borman and James Lovell spent 14 days in the cramped cockpit in the photo above from December 4 to 18, 1965. The two hatches have been removed, making the cabin seem roomier than it really was. Each astronaut had only a small window in front of his face.  

Their mission was primarily medical. They endured experiments regarding food, waste, and sleep. Gemini VII also served as the target vehicle for Gemini VI-A during the world’s first space rendezvous. 

Learning to Rendezvous in Space 

The Apollo command and lunar modules had to link up after a lunar landing. NASA used the Gemini program to practice rendezvous and docking in space.  

Gemini VI was supposed to dock with an Agena rocket stage, but the Agena failed to reach orbit. So when NASA launched Gemini VII on a 14-day medical mission in late 1965, it also launched Gemini VI, renumbered to Gemini VI-A because of the changed mission, to meet up with it. The two spacecraft successfully rendezvoused. In 1966, Gemini VIII succeeded in docking with an Agena. 

A three-quarters view of a conical shaped command module floating above the earth. The edge of the spacecraft taking the photo can be seen in the bottom lefthand corner.
Thomas Stafford on Gemini VI-A took this photo of Gemini VII during their rendezvous on December 15, 1965. Image courtesy of NASA. 

 

Learning to Live in Space 

Flying to the Moon would require missions lasting over a week; it took three days just to get there. No Mercury astronaut had spent more than 34 hours in space. Gemini missions needed to prove that humans could live in weightlessness for up to two weeks. Three Gemini missions in 1965 extended time in space from four to 14 days. 

 

A black box with two eyepieces and 10 yellow cards stored in the top, used for eye testing.
Gemini astronauts tested the impact of weightlessness on their vision. Gordon Cooper and Charles “Pete” Conrad used this testing device during Gemini V. Image courtesy of the Smithsonian.
A small rectangular yellow card incased between two pieces of clear plastic. The area at the top of the card denoting the pilot name is marked with a B, presumably for Frank Borman. The rest of the card has different numbers recorded related to different optical measurements.
Frank Borman and James Lovell used the vision test card during Gemini VII. Note the "B" for Borman written next the space for "Pilot" on the card.

Learning to Walk in Space 

To walk on the Moon or perform useful tasks in space, astronauts had to be able to leave the spacecraft—what NASA called extravehicular activity, or EVA. EVA proved more difficult than expected. Astronauts became overheated and exhausted. It took NASA until the last Gemini mission to refine the techniques and equipment to make spacewalking effective. 

An astronaut floating in space. The Earth can be seen below in the bottom half of the frame. The astronaut holds out a long metal rod in one hand.
On June 3, 1965, Edward White became the first American to walk in space. (Soviet cosmonaut Aleksei Leonov was the first person to do so.) Note the maneuvering gun in his right hand and his Gemini IV spacecraft reflected in his visor. Image courtesy of NASA.
Hand-Held Maneuvering Unit
White used this device to perform simple maneuvers while outside the spacecraft during his historic spacewalk. The two tanks produced less than 20 seconds of maneuvering gas. Image courtesy of the Smithsonian Institution.

The Gemini program was an essential step for NASA in getting humans to the Moon. See a short summary of each of the 10 missions below.  

Name Launch Date Astronauts Duration Mission
Gemini 3 Mar. 23, 1965  Virgil “Gus” Grissom,
John Young 		 4:53 hours  3-orbit spacecraft test 
Gemini IV June 3, 1965  James McDivitt,
Edward White 		 4 days  EVA, medical 
Gemini V Aug. 21, 1965  Gordon Cooper,
Charles Conrad 		 8 days  Medical, rendezvous test 
Gemini VII Dec. 4, 1965  Frank Borman,
James Lovell 		 14 days  Medical, rendezvous with G VI-A 
Gemini VI-A Dec. 15, 1965  Walter Schirra,
Thomas Stafford 		 1 day Rendezvous with G VII
Gemini VIII Mar. 16, 1966  Neil Armstrong,
David Scott 		 10:41 hours Dock w/ Agena; emergency return
Gemini IX-A June 3, 1966  Thomas Stafford,
Eugene Cernan 		 3 days Rendezvous, EVA 
Gemini X July 18, 1966  John Young,
Michael Collins 		 3 days Rendezvous and dock, EVA 
Gemini XI Sept. 12, 1966  Charles Conrad,
Richard Gordon 		 3 days Rendezvous and dock, EVA 
Gemini XII Nov. 11, 1966  James Lovell,
Edwin “Buzz” Aldrin 		 4 days Rendezvous and dock, EVA 

 

Related Topics Spaceflight Gemini program Human spaceflight Records and Firsts
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