[AR] Re: SpaceX F9 Launch/Update -- Live Link

  • From: David Gregory <david.c.gregory@xxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Tue, 29 Dec 2015 12:48:35 -0800

It was stated that GG engines are lighter than alternatives. At a given
chamber pressure, that's not the case.

On Dec 29, 2015, at 12:40 PM, David Weinshenker <daze39@xxxxxxxxxxxxx> wrote:

On 12/29/2015 12:02 PM, David Gregory wrote:
There is nothing magical about the GG cycle that makes it lighter.

No, there's nothing "magic" about gas generator cycles - they're a
simple, effective solution. There's something a bit "demonic" about
staged combustion cycles (from the engine development point of view),
though; it's much harder to develop such an engine incrementally: you
sort of have to get everything working at once in order to test-run
anything.

I heard that a number of SSME prototypes were consumed in the
process of discovering a safe startup sequence... it wouldn't
surprise me if there were similar experiences "over there",
during the initial development of the RD-180.

-dave w



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