Malfunction Reaction Systems

Expendible vehicles - design to be tolerant to single point failures.

Failure modes analysis
- looks at engine components
- ways it can fail
- how failure affects operation
- identify failure modes

Centaur - when engine start signal given, detection system tells if engine doesn't come up. 
If one fires and the other doesn't, the vehicle tips.
Guidance - asked to detect tip and shuts engines off if vehicle tips.

Trys new start sequence.

AC71 failure occurred several hundred miles downrange. On second attempt, good engine came 
up again, second failed again.
One restart attempt permitted.
With EMA, electronic control - other things can be done. (~what?)

Range Safety Officer - determines what to do with rocket.

Side note - must shut down engines before destroying aircraft.