"We've got serious problems here. We're tumbling end over end, and we've disengaged from the Agena."
That ominous message from the two-man spaceship Gemini 8 alarmed a nation grown accustomed to uninterrupted space success. Off Formosa, aboard the tracking ship Coastal Sentry tense NASA technicians followed the approaching capsule by radar and urgently queried Astronauts Neil Armstrong and David Scott for additional information. In the Mission Control Center near Houston, flight controllers huddled over their consoles and studied telemetered data in a desperate effort to track down the trouble. Millions of Americans listened in startled silence as NASA's Paul Haney, his usually calm voice urgent and shaken, announced over television and radio that Gemini 8 was in danger.
What made the pews even more difficult to believe was that the day had begun with almost letter-perfect precision. And now, after the flawless twin launch of the Agena target vehicle and the Gemini, after making space rendezvous seem almost routine, and after the first successful docking of two spaceships, something had gone wrong.
Gemini 8's ordeal began shortly after its docking triumph, when Armstrong and Scott began a program of planned maneuvers to test the stability of the Gemini-Agena system. As they passed within range of the tracking station at Tannanarive, in the Malagasy Republic, Command Pilot Armstrong reported that he had easily swung the Gemini-Agena combination around 90°. "It's gone quite well," he reported, just before he passed out of radio range.
Next, the astronauts sent an electronic signal that was supposed to start the Agena's tape recorder, already programmed to fire the Agena's attitude thrusters and begin a series of gentle maneuvers. Instead, the Gemini-Agena began to gyrate violently through space, yawing and rolling at a rapidly increasing rate. Unable to stabilize the joined spacecraft, Armstrong resorted to a last-ditch maneuver: he undocked.
Once freed though, Gemini began to roll even more rapidly.
"Violent Oscillations." High over Southeast Asia, the tumbling spacecraft came into range of the Coastal Sentry. "It's in a roll, and we can't seem to turn anything off," Armstrong informed the shipboard controller, who reported to Houston that Gemini was now "showing' pretty violent oscillations." It seemed to Armstrong that Gemini's No. 8 thruster -one of the small rockets used to turn or yaw the craft-had stuck open and was pushing the craft into an uncontrollable spin, which at one point reached a critical rate of a complete revolution each second.
Fighting to regain stability, Armstrong took another emergency step. He began firing Gemini's re-entry attitude-control rockets, which are designed to be used only to position the capsule properly as it re-enters the atmosphere on its way back to earth. "We are regaining control of the spacecraft slowly," he reported. By the time Gemini was out over the Pacific, it was getting back on even keel, sailing serenely through space only a few miles away from the Agena, which had been re-stabilized by radioed commands from ground controllers. "O.K., relax," the Coastal Sentry controller advised the astronauts. "Everything is O.K."