A stuck thruster and an uncontrolled spin

Armstrong tried to stop the roll using the OAMS thrusters, but it immediately resumed. With OAMS fuel dropping toward 30%, the crew suspected the problem might lie with the Agena and decided to undock.

After undocking, the spin actually got worse — confirming the problem was on Gemini itself, not the Agena. The cause was an electrical short (likely a static-electricity discharge) that kept one OAMS thruster firing continuously even when switched off. The spin rate reached 296 degrees per second — more than one full rotation every second.

Armstrong shut down the entire OAMS and used the Reentry Control System (RCS) thrusters on the nose of the spacecraft — originally intended only for reentry — to stop the spin. Regaining control took nearly thirty minutes and consumed almost 75% of the reentry fuel. Under NASA rules, once the RCS had been used, the mission had to end in an immediate emergency landing. Scott later said: "The guy was brilliant. He knew the system so well. He found the solution, he activated the solution, under extreme circumstances ... it was my lucky day to be flying with him."