"Kim Keller" wrote in
:


"Rand Simberg" wrote in message
.. .
I think that their consensus preference is a single solid (SRB
based).

Marshall is pitching that idea pretty hard. I hope it goes the way of
all Marshall projects.

There was an NASA-internal study performed last year which concluded
that segmented solids are more dangerous than monolithic solids. The
study examined US launch failures over the past twenty years and
evaluated the potential for a safe crew abort in each case, had a
vehicle health monitoring/abort system been installed. Even the Delta
II which suffered an SRM failure at about 1100' was judged to have
been an abortable event.

If I recall correctly, that was a GPS launch and the main explosion
was touched off by the ruptured solid motor that lit off the
detonation cord, which proceeded to unzip the rest of the Delta
on extremely short notice. Range safety was just as surprised as
everyone else. And I believe the GPS hit the beach essentially
intact along with the Star-something solid third stage.

That's a problem with safety systems; sometimes they are TOO
effective. But I'm not sure if a different system on a manned
launcher could have given enough time for an escape system to save
the crew, under the same circumstances.

How lucky do you feel, eh? Solids work well, but when they
go bad, they almost always go very badly, very uncontrollaby.

--Damon