[AR] Re: thinking big once more
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Fri, 30 Sep 2016 12:12:48 -0400 (EDT)
On Fri, 30 Sep 2016, John Dom wrote:
Correct me if I?m wrong, but I do not think there ever was a rocket of
which an engine (cluster or not) exploded which did not become toast. I
said exploded, not malfunctioned / flamed out.
Falcon 9 #4: engine explosion (not a "malfunction", not a "flameout" --
an explosion) followed by successful insertion into orbit.
The SpaceX press releases, and later statements about investigation
results, were cleverly worded to make you think the engine was still
running and shut down on command, but if you read them very carefully,
they do not actually say that. Which is itself quite revealing.
This was in fact a bit surprising. Engine explosions *usually* don't end
well. However, liquid-engine failures are usually not explosions, given a
sensible control system which shuts down the engine when disaster is
clearly imminent. Usually the engine either doesn't start at all, or just
suddenly shuts down.
(There were problems in the early days, on Atlas in particular, with
control systems which assumed that if a weapon built to fight World War 3
couldn't complete its mission, nobody cared what happened to it. The
fallacy in this became evident quickly, when test stands started being
destroyed by explosions that could have been prevented if the control
system had, e.g., shut down an engine whose turbopumps were about to start
sucking air.)
Henry
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