"Kim Keller" wrote in message
...

"Craig Cocca" wrote in message
oups.com...
1) Are there any examples of an expendable rocket shutting its engines
down when a failure mode is detected, or do non-human-rated vehicles
only "fly or explode"? The only recent example I could think of where
the launcher shut itself down when something had gone wrong is on the
maiden launch of Space X's Falcon 1.

Engine shutdown is a range safety option the expendable rocket builder can
use instead of destruct charges. AFAIK, only SpaceX has gone that
direction. I don't know why other builders haven't chosen it.

I was discussing this with some coworkers today. It seems that all US ELVs
execute an engine shutdown command as part of the range safety destruct
command sequence. The engine shutdown command is intended to shut down an
engine that may otherwise continue operating for a brief period after the
rocket comes apart. This was evidently a "lesson learned" from the early
days of the rocket bidness. The destruct charge is necessary to prevent the
rocket from becoming an *intact* powered projectile. SpaceX was able to fly
without a full flight termination system at Kwaj, but will have to use one
when operating out of Vandenberg or CCAFS.