Gemini VIII Neil Armstrong Agena Docking & Abort: “Gemini 8, This is Houston Flight” 1966 NASA

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“The historic first docking in space with the Agena is completed. Camaras record the harrowing experiences of the astronauts as Gemini VIII wildly gyrates through space following a malfunction. The spacecraft is separated from the Agena, brought under control and reentry is achieved.”

Public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and 1-pass exposure & color correction applied (cannot be ideal in all scenes).
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

Gemini 8 (officially Gemini VIII) was the sixth manned spaceflight in NASA’s Gemini program. The mission conducted the first docking of two spacecraft in orbit, but suffered the first critical in-space system failure of a U.S. spacecraft which threatened the lives of the astronauts and required immediate abort of the mission. The crew was returned to Earth safely. The only other time this happened was on the flight of Apollo 13.

It was the twelfth manned American flight and the twenty-second manned spaceflight of all time (including X-15 flights over 100 kilometres (62 mi)). Command pilot Neil Armstrong’s flight marked the second time a U.S. civilian flew into space (Joseph Albert Walker became the first US civilian on X-15 Flight 90). Armstrong had retired from the United States Navy in 1960. The Soviet Union had launched the first civilian, Valentina Tereshkova (also the first woman) aboard Vostok 6 on June 16, 1963…

Agena

Five months earlier, NASA had tried to launch an Agena along with Gemini 6, but the Agena blew up on launch and the Gemini launch was postponed. This time everything worked perfectly. The Agena put itself into a 298-kilometer circular orbit and oriented itself to the correct attitude for the docking. The Gemini spacecraft itself was launched into a 160 by 272 kilometer orbit by a modified Titan II at 10:41:02 a.m. EST…

They found at 332 kilometres (206 mi) from the Agena that the radar had acquired the target…

After several small burns they were 46 meters away and with no relative velocity. After 30 minutes of visually inspecting the Agena to make sure that it had not been damaged by the launch, they were given the go for docking… In a matter of minutes, the Agena’s docking latches clicked and a green light indicated that the docking had been successfully completed. “Flight, we are docked! Yes, it’s really a smoothie,” Armstrong radioed to the ground.

Emergency

There was some suspicion on the ground that the Agena attitude system was acting up and might not have the correct program stored in it (this suspicion was subsequently found to be incorrect). Just before they went off contact with the ground, the crew of Gemini 8 were informed that if anything strange were to happen, they were to turn off the Agena.

After the Agena began execution of its stored command program, which instructed the Agena to turn the combined spacecraft 90° to the right, Scott noticed that they were in a roll. Armstrong used the Gemini’s Orbit Attitude and Maneuvering System (OAMS) to stop the roll, but the moment he stopped using the thrusters, it started again. They immediately turned off the Agena and this seemed to stop the problem for a few minutes. Then suddenly it started again.

Scott noticed that the Gemini attitude fuel had dropped to 30% indicating that it was a problem on their own spacecraft. They would have to undock. After transferring control of the Agena back to the ground they undocked and with a long burst of translation thrusters moved away from the Agena.

It was at that point that the Gemini spacecraft began to roll even faster, and approached one revolution per second. The astronauts were now in danger of impaired vision and loss of consciousness due to the violent motion. At this point Armstrong shut down the OAMS and used the Re-entry Control System reaction control system (RCS) to stop the spin. After steadying the spacecraft, they tested each OAMS thruster in turn and found that Number 8 had stuck on. Mission rules dictated that the flight be terminated once the RCS had been fired for any reason, so Gemini VIII prepared for an emergency landing…

The original plan was for Gemini 8 to land in the Atlantic, but that was supposed to be three days later. So USS Leonard F. Mason started to steam towards the new landing site 800 kilometers east of Okinawa and 1,000 kilometers south of Yokosuka, Japan…

Planes were also dispatched and the pilot of one (Captain Les Schneider, USAF), managed to see the spacecraft as it descended precisely on time and target…

No conclusive reason for the thruster malfunction was found. The most probable cause was determined to be an electrical short…