Brian Thorn wrote:
On 5 Nov 2005 10:53:32 -0800, "Ed Kyle" wrote:

Boeing "strike breaking" nonunion workers will process the Pluto New
Horizons Star 48
upper stage, according to:

"http://www.flatoday.com/apps/pbcs.dll/article?AID=/20051105/NEWS02/511050329/1007"

Heads up Florida!

Well, technically it should be "Heads up, Australia" or someplace. The
Star 48 doesn't fire until late in launch...

Brian

Well, it depends on the failure mode postulated for the Star 48. If
the failure occurs after the end of the 2nd Centaur burn, then the
remaining stack (Centaur + Star 48 + New Horizons) is already in an
Earth escape trajectory. If there is no 3rd stage separation, the
stack will end up in solar orbit. Ditto if Star 48 separates but fails
engine start. The only way it might come back to Earth is if the stage
mis-orients and does an "ocean injection burn" a la Landsat 6.

OTOH, if there was a Star 48 processing problem that led to an
inadvertant stage separation or structural breakup during earlier
phases of launch, then it could be "heads up, Florida", or anywhere
along the ground track. The Environmental Impact Statement describes
failure probabilities and consequences for each phase of launch. One
interesting note is that the Star 48 for New Horizons has an additional
flight termination breakup system to prevent an intact stage from doing
a hard crunch of the spacecraft and RTG harder into the ground.