Re: How many times?
Well the shuttle engines themselves NEVER failed
Yes, they did. STS-51-F had to abort-to-orbit because of an SSME shut down. STS-93 lost a small pin that was violently ejected into the engine nozzle and punctured the cooling lines, which led to a below-target orbit, and almost lost two engines with a separate digital control unit failure. There were also five pad aborts because of SSME misbehavior.
Biting the hand that feeds IT
