Re: Instant Shuttle turnaround ?


"Damon Hill" <damon1SIX1@xxxxxxxxxxxxxx> wrote in message
news:Xns9B6985C9C51F4damon161attbicom@xxxxxxxxxxxx
My preferred idea for a "new Shuttle" would be along the lines of two
essentially identical airframes; one a kero-lox booster with minimal
TPS if any at all, and the other a hydrogen-lox orbiter with metallic
shingles instead of ceramic tiles. They'd launch in tandem and the
booster would return to launch site. No solids and no linear aerospike
engines; conventional RD-180 or RD-191 and SSMEs/RL-10 engines, and
alcohol/LOX/peroxide thrusters. Otherwise it's just a scaled up
X-33-like 'Bimese' concept as has been proposed several times over the
decades.

A friend at work had a co-worker at another job that used to say, "Things
that are different, just aren't the same." That applies here. Your two
stages may *look* the same, but they will end up being vastly different
because of the different flight regimes, fuels, engines, and etc. Beyond
that, there is the temptation for engineers to "tweak" the stages to be even
more different than they absolutely need to be, most likely to save weight
since traditional aerospace engineers get caught up in thinking that
minimizing weight (or minimizing the dry mass to payload ratio) is THE
variable to optimize in a design.

In the end, you'll have to pay to develop two completely different reusable
stages that only appear to be the same to the untrained eye.

Of course no one's developing such a system; any new launch systems are
conventional derivatives of known technology such as SpaceX is doing
with Falcon and Dragon--because it's probably cheaper to develop.

And they're proving that there is room for improvement even for expendable
designs.

But I think we're really going to miss Shuttle's capabilities, and that
will eventually drive development of new Shuttle-like systems.

Perhaps, or we'll adapt and start placing much of the shuttle's capabilities
elsewhere, like on a space station (e.g. the ISS has *two* airlocks, the
SSRMS, and etc.), or perhaps even a manned reusable tug once we finally get
off our behinds and develop in orbit refueling.

Barring ISS, reuse of hardware that's already been launched is something
NASA has not done enough of. Spacelab is a perfect example of this. That
hardware supported a mission of less than two weeks followed by months or
years of sitting on the ground. While that's hardly the best use of such
hardware, it was the only use that the shuttle would support due to its
infrequent flights.

Jeff
--
beb - To paraphrase Stephen Colbert, reality has an anti-Ares I bias.



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