Agena target vehicle

The Agena Target Vehicle was an uncrewed spacecraft used by NASA during its Gemini program. Its main job was to help astronauts learn how to meet and connect with another spacecraft in space. This was very important because it helped get ready for the Apollo program moon missions.

The spacecraft was built using a part of Lockheed Aircraft's Agena-D rocket, with a special connecting part made by McDonnell Aircraft. It was about 26 feet long and 5 feet wide, and it flew into space using the Atlas-Agena rocket. It carried a lot of fuel to move around in orbit.

Sadly, one of these spacecraft failed to launch for the Gemini 6 mission. Because of this, NASA made a smaller backup called the Augmented Target Docking Adapter. This was used for Gemini 9A after another launch failed, but it also had some problems during the mission.

Operations

Each ATV was made up of a special upper rocket stage built by Lockheed Aircraft and a docking part built by McDonnell Aircraft. The Agena was launched from Cape Kennedy's Launch Complex 14 on top of an Atlas booster made by General Dynamics. After launch, the Agena would fire its engine to enter orbit.

The Gemini spacecraft would then be launched and would meet up with and connect to the Agena. Once connected, the astronauts could control the Agena's engines and thrusters. They used this to do several experiments, such as stabilizing the combined spacecraft, practicing spacewalks, and changing the spacecraft's orbit. They also tested flying the spacecraft in a special way using a tether between them to see how gravity would affect it. After undocking, the Agena would continue to operate on its own, performing more tests and moving to different orbits.

The first launch of an Agena Target Vehicle happened in October 1965, but the engine exploded, so the planned Gemini mission was changed to meet up with another Gemini spacecraft instead. The problem was found to be with how the engine was started, and fixes were made for future launches.

Augmented Target Docking Adapter

After the first problem with the Gemini spacecraft, NASA asked McDonnell to create a new docking target without the Lockheed Agena rocket. This new target was called the Augmented Target Docking Adapter (ATDA). It included parts from the Gemini spacecraft and was 10.9 feet long and weighed 1,750 pounds.

When the Gemini 9 mission was getting ready to launch, there was a problem with the rocket. The rocket began to turn and fall back to Earth, so it could not reach space. Later, another mission called Gemini 9A used the ATDA. However, a cover that should have opened did not fully come off, making docking impossible. The astronauts practiced moving close to the spacecraft instead.

Flight statistics

Target	Gemini mission	Launched	Reentered	NSSDC ID	Gross mass in orbit	Comments	Photo
GATV-5002	Gemini 6	October 25, 1965 15:00:04 UTC	October 25, 1965 15:06:20 UTC	GEM6T	N/A	Atlas-Agena exploded during launch. Gemini 6A achieved first rendezvous with Gemini 7 instead.
GATV-5003	Gemini 8	March 16, 1966 15:00:03 UTC	September 15, 1967	1966-019A	7,117 pounds (3,228 kg)	Achieved first docking, but mission soon aborted due to stuck Gemini thruster. ATV later used as secondary target on Gemini 10.
GATV-5004	Gemini 9	May 17, 1966 15:12:00 UTC	May 17, 1966 15:19:00 UTC	GEM9TA	N/A	Failed to orbit.
ATDA No. 02186	Gemini 9A	June 1, 1966 15:00:02 UTC	June 11, 1966	1966-046A	1,750 pounds (794 kg)	No Agena rocket. Successful rendezvous, but no docking due to shroud separation failure.
GATV-5005	Gemini 10	July 18, 1966 20:39:46 UTC	December 29, 1966	1966-065A	7,236 pounds (3,282 kg)	Boosted Gemini 10 to 412-nautical-mile (763 km) apogee.
GATV-5006	Gemini 11	September 12, 1966 13:05:01 UTC	December 30, 1966	1966-080A	7,271 pounds (3,298 kg)	Boosted Gemini 11 to record 739.2-nautical-mile (1,369.0 km) apogee. First demonstration of artificial gravity created in microgravity.
GATV-5001A	Gemini 12	November 11, 1966 19:07:58 UTC	December 23, 1966	1966-103A	7,117 pounds (3,228 kg)	No apogee boost due to defective Agena engine. Performed tether experiment.

In popular culture

The docking of Gemini 8 with the Agena spacecraft was shown in the first episode of the 1998 HBO miniseries From the Earth to the Moon, and in the 2018 movie First Man about Neil Armstrong.

This event was also part of a short science fiction film called DARKSIDE, made for a film festival in London in 2020.