Exploring the Unknown: Selected Documents in ... - The Black Vault

Exploring the Unknown 361
Armstrong:
Shortly after backing off, we noticed that we were essentially losing control
of the spacecraft in roll and yaw and we suspected that we were over
the life-time of these attitude thrusters. The spacecraft was continuing,
however, to accelerate, and we were obtaining rates in roll at least that
approached 200 to 300 degrees per second, or perhaps more.
Scott:
Yes, I would agree with that. It looked like even more to me, and it was by
far more in roll than in yaw. The roll was the most predominate.
Armstrong:
We realized that physiological limits were being approached, and that we
were going to have to do something immediately, in order to salvage the
situation. So, we turned off all the OAMS thruster circuit breakers, closed
the Attitude Control Power Switch, [61] closed the Motor Valves, armed
the RCS, had no effect using the ACME, and went to DIRECT.
Scott:
I might add in there that the rates were high enough that both of us had
trouble seeing the overhead panel due to the vertigo problems and the
centrifugal force as we went around.
Armstrong:
The RCS DIRECT DIRECT was working satisfactorily and as soon as we
determined that we were able to reduce the rates using this mode, we
turned the A-Ring OFF and reduced the rates slowly with the B-Ring,
putting in a pulse to reduce the rate, then waiting awhile, then putting in
another pulse, and so on until the rates were essentially zero in all areas.
At this time we carefully reactivated the OAMS, found some popped or
inadvertently manually actuated circuit breakers, OAMS control and so
forth. Upon reactivating the system we found that the Number 8 thruster
was failed on, so we left that circuit breaker off. We had no other yaw
thrusters with the exception of Number 8 but the pitch was apparently
starting to come back in and we ensured that the roll logic was in pitch.
We stayed in PULSE, controlling the spacecraft with pitch and roll pulses
then to essentially a BEF attitude. [62]
Scott:
Do you want to add in there about the hand controller, in not getting
anything?
Armstrong:
Yes. When I earlier referred to the fact that I’d lost control completely it
appeared to us as though at that time we had no control out of the hand
controller in any axis. I might reiterate that we reactivated the OAMS and
found no roll or yaw control with the Number 8 circuit breaker off but
pitch was slowly coming back then. It was somewhat ineffective at first,
but it was usable after awhile. Sometime later we saw the Agena, approxi-