A few days ago the anniversary of a space milestone was remembered. It was starred by Neil Armstrong, the same as later would reach the Moon. It was the first spatial coupling between two ships. But it was not easy, and it had dramatic episodes. But it was still a memorable milestone, worth remembering.
Armstrong and David Scott were launched on a Gemini 8 ship on March 16, 1966. They left aboard a Titan III rocket from Cape Canaveral. Three hours earlier, their target, an Agena unmanned vehicle, took off on an Atlas rocket.
The Gemini 8 mission was planned for three days. In them, Armstrong and Scott would meet with the target vehicle Agena-D and perform four connection tests. There were six hours of flight, with five orbits and nine encounter maneuvers. Armstrong closed the distance between the Gemini and Agena and proceeded to dock. Within minutes, the Agena's connecting latches closed. A green light indicated that the pairing was completed successfully.
Soon after, the problems began. The Agena vehicle began executing its attitude control program, which maneuvered the linked ships to turn 90 degrees to the right. Scott realized that Gemini 8 was already spinning. Armstrong used his ship's thrusters to stop him. But after stopping, the process immediately started again.
Armstrong reported that the fuel in the powertrain had been reduced to 30 percent. That indicated that the problem could occur in his own spaceship. They decided to decouple from Agena so they could analyze the situation. Scott switched Agena's control to ground command, while Armstrong struggled to stabilize the vehicle. At least enough to allow decoupling. Scott then pressed the undock button, and Armstrong fired a long burst of travel thrusters to get away from Agena.
Without the added mass of the Agena, the Gemini's turning speed began to accelerate rapidly. It reached one revolution per second. That caused the astronauts to have blurred vision, putting them in danger of unconsciousness. Armstrong used the Reentry Control System (RCS) thrusters to stop the turn.
After stabilizing the spacecraft, they tested each propeller one by one. Number 8 was found to have been left on. Nearly 75 percent of the reentry maneuver fuel had been used to stop the turn. Under the mission rules, the flight would be canceled once the RCS was used for any reason. Gemini 8 immediately prepared for an emergency landing.
It was decided to allow the ship to continue one more orbit so that it could moor where the recovery forces reach it. The original plan was that Gemini 8 would land in the Atlantic. But it ended up being in the Pacific, 800 kilometers east of Okinawa, Japan. The astronauts were recovered safe and sound. Even with problems, they had achieved the first spatial coupling.