Re: Is Crew Launch Vehicle Too Big?
- From: "Ed Kyle" <edkyle99@xxxxxxxxxxx>
- Date: 27 Oct 2005 12:57:19 -0700
Brian Thorn wrote:
> On 26 Oct 2005 12:05:29 -0700, "Ed Kyle" <edkyle99@xxxxxxxxxxx> wrote:
>
> >Most importantly,
> >the stage could use a less-powerful upper stage engine
> >than the planned SSME that would almost certainly
> >require far fewer man-hours to build and test and fly.
>
> Unless you've already paid for the engines. In which case the cost of
> prepping existing engines must be more than the cost of building *and*
> prepping new engines to make the new engine the better choice. I tend
> to doubt a new J-2S production line, testing, and training on the new
> engine will be cheaper than updating SSME for air-start (changes
> mostly outside the engine, by the way) and using already-trained
> engineers. And by the way, J-2S has never flown, the original J-2 had
> three in-flight failures. SSME failed only once, 20 years ago, and
> requires no infrastructure changes for testing and servicing. You're
> getting a better engine for the cost of a bigger vehicle.
There might be alternatives to J-2S too. Pratt has
done some development work on RL-60, as has Mitsubishi
(Boeing) on MB-60. A cluster of such engines,
especially of the relatively simple RL-60, could be
cheaper than the big single-engine NASA alternatives.
> At this point, NASA needs to start actually building new engines
> again. But they'll need SSME (or RS-68) for the Heavy Lifter anyway,
> so there are economies of scale to go with SSME for the Stick.
This presumes that the heavy lifter will ever be built,
which I think is unlikely. I think it more likely that
Griffin's plan will be truncated into a scaled back
non-shuttle-based LEO/ISS U.S. human space program.
> >The simple scale of the machine also effects costs.
> >A bigger, heavier machine will require bigger, more
> >costly, ground processing facilities for example, which
> >will take more man-hours to build and maintain. And
> >every processing step, including simple steps like
> >lifting the payload, will take fractionally more
> >man-hours that will inexorably add up over time.
>
> The ground processing facilities already exist whether you choose EELV
> or Shuttle-derived. Maintenance will be far more for the VAB than
> either EELV or Falcon, but you're paying for VAB for the Heavy Lifter
> anyway.
Some of the building shells might exist (assuming VAB
was used, etc), but much of the ground infrastructure
does not exist for an SRB-Stick launcher. A completely
new 300 foot tall set of fixed and mobile service towers
will be needed, for example. Entirely new facilities
will be needed to process the second stage and CEV
payload, etc.
If NASA were brave enough to admit now that the heavy
lifter is never going to be built, the Agency could
save gigabucks long-term by scrapping Complex 39 and
starting over with a slimmed down launch site just for
Stick.
- Ed Kyle
.
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