"Alberto Monteiro" <[EMAIL PROTECTED]> wrote:
>
>A reusable rocket is simply a waste of fuel.
>
>This might only be justified if the fuel was much more cheap than the
>circuitry etc.
Is the fuel really that expensive?
The limiting factor doesn't seem to be cost of materials, but cost of labor.
Shuttle takes a team of hundreds several months to get ready. The
100%-reusable SSTO proposals for X-33 both aimed at 2-7 day turnarounds with
a handful of people involved, with materials being the cost of fuel. While
that is probably unrealistic for our first SSTO attempt (maybe 20-70 days
and 50 people?), Shuttle could NEVER have had a turn around that fast - just
getting the orbiter from the landing site to the VAB, mated with the tanks
and boosters and out to the pad takes twice that long (numbers off the top
of my head). Each shuttle flight appears to cost $500 million, and surely
the fuel is only a tiny fraction of that.
>From a purely "energy cost to put cargo in orbit", SSTO is a bad idea. From
a financial motive - especially wanting to drive the price down so that I
can afford to go - SSTO is still a good idea, IMHO.
Given a demand, it seems to me that the production of fuel can be made
cheaper much more easily than manufacturing of disposable components.
> >(Who still is betting on uploading vs. physically getting to orbit.)
> >
>Upload to *what*? Something must be on orbit...
Yes, but if I'm waiting in line for a ticket I'll likely be dead before the
price drops enough for me to afford a ticket. There will also be a few
billion people more able than I am to take the trip physically. If I'm a
light beam, I'm extremely cheap to transmit, and a few billion of us
emigrees can pool our money to send up the hardware the old fashioned way.
Zubrin's "The Case For Mars" points out that any project that will take 20
years and require building up infrastructure and new technologies won't
happen - it's just too long term for governments to pay for. So he proposes
essentially a 5-10 year "let's do it now, cheap" trip to Mars. Great idea -
it could be done using current technology with no build-up. But (A) even it
won't since the current tone of the US government is anti-space, and (B)
even if it did, the lack of infrastructure means it is of no use to *me*,
unless I want to pay for the next Mars Direct mission out of pocket.
Joshua
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