Re: Fill'R'Up

On Sep 27, 8:51 am, Fred J. McCall <fmcc...@xxxxxxxxxxxxx> wrote:
Len <l...@xxxxxxxxxxxxxx> wrote:

:On Sep 25, 4:18 pm, simberg.interglo...@xxxxxxxxx (Rand Simberg)
:wrote:
:> On Tue, 25 Sep 2007 11:56:51 -0700, in a place far, far away, Hop
:> David <h...@xxxxxxxxxxx> made the phosphor on my monitor glow in such
:> a way as to indicate that:
:>:> >Rand Simberg wrote:

:>
:> >> A piece in Popular Mechanics on propellant depots, and their benefits:
:>
:> >>http://www.popularmechanics.com/science/air_space/4224660.html?series=35
:>
:> >In a recent discussion on atmospheric drag and gravity penalty you
:> >linked to Jon Goff's blog. Evidently you have a high regard for his
:> >opinions.
:>
:> On some subjects, yes. ;-)
:>
:> In fact, I linked to him in the post last night in which I linked to
:> the Popular Mechanics piece:
:>
:>http://www.transterrestrial.com/archives/009761.html#009761
:>
:> There's a lot of discussion over there.
:>
:> I like the comment that one person had analogizing it to a B-52. If
:> NASA ran the Air Force, it (and Fred McCall) would launch a B-52 with
:> tanks fully loaded, to deliver a few hand grenades over the enemy.
:>
:
:I like it.
:

See my statements elsewhere about what a stupidly ignorant remark it
is that you 'like'.

:
:Another analogy that seems to fit:
:We took a wrong turn at a fork in the road
:45 years ago. Fred seems even more
:reluctant than NASA to go back to the fork
:to try it the right way.
:

You have yet to demonstrate that your way is "the right way" any more
than NASA's was.

I have posted elswhere in this thread that I
think the reason we seem to have such a
complete disconnect on this subject, Fred,
is that oribtal propellant depots and other
on-orbit operations enable a completely
different architecture. This architecture
potentially, at least, can result in an entirely
different economic realm. True enough,
the difficulty and cost of on-orbit operations
with frequent, reliable, low-cost access to
LEO is yet to be proven. However, many of
us do not feel that this should be too difficult
a leap of faith. Moreover, proving that on-orbit
operations become much simpler and less
costly could be a good initial business for a
space transport.

Assuming for the moment that on-orbit operations
with a good space transport to give frequent,
reliable, low-cost access to space is not the
killer you suggest, then the availability of
propellants, filled tanks, and/or propulsion
modules in LEO for a transport cost of $500/kg
is clearly less costly than the differential cost
of direct flight versus depot-assisted flight. IMO,
our design for a space transport can make such
costs attainable without any need for exotic
technology or even new engines.

:
:Traffic level is perhaps the main factor for a
:radical reduction in the cost of LEO access is
:traffic level.
:

Well, this is kind of a given, but you have a real chicken/egg problem
with regard to your 'frequent flights' being fuel lifts to support a
market that isn't there yet. Do your numbers include cost of money
and inventory and such, holding all that fuel until the users
materialize (if they do)?

The chicken/egg problem is real. The
market does have to be ready pretty much
when the vehicle is. That is why we don't
count exclusively on the propellant-depot
market. However, the "experimenting on-orbit
market" could reasonably be there when the
vehicle is ready.

:
:I firmly believe that closure
:is quite possible with respect to: 1) a profit-
:making capability for delivering, e.g., a billion
:dollars per year worth of propellant (or filled
:tanks or filled propulsion modules) to LEO
:in 3000-kg chunks for $500/kg or less; and
:2) a greatly expanded, yet far less costly,
:deep-space exploration program.
:

I don't see how you can make the preceding claim when you haven't even
figured out just what it is you're going to be putting up there.
Rather difficult to do the cost trade-offs when you don't know if you
need fuel storage and transfer facilities or on-orbit assembly of a
bunch of relatively small fuel tanks or propulsion modules.

Yes, there are a lot of tradeoffs. However, the
basic assumption is that when the tradeoffs are
done, there will be a market for one approach or
another--or perhaps several approaches. We
really don't care too much what type of cargo
we carry aside from hazard and legal problems.
Even density/volume problems can be handled
with appropriate premiums for low-density transport.
That's generally the way commercial tranporation
works.
:
:Sure, there are procedures to prove. I also
:firmly believe that an experimental operational
:program in LEO would quickly establish the
:reliability of one or more "filling station"
:strategies.
:

I don't believe anyone is claiming technical infeasibility. The
question to my mind is cost effectiveness once you include total
costs.

I agree that there is much left to prove with respect
to on-orbit operations. I just don't see it as a likely
show-stopper the way you do.
:
:The key is frequent, reliable,
:low-cost access to LEO. IMO, this "no -brainer"
:has been ignored for too long. [That's
:an opinion, Fred, not an unsubstantiated
:statement :-) ].
:

It's not so much a case of this having been ignored as it being a
question of just how you get there.

First we build a good space transport. I believe
that this can be justified on a purely commercial
basis. And this justification does not depend
soley on the feasibility of large-scale on-orbit
operations.

Once we have a good space transport, then a
modest amount of money can demonstrate the
feasibility and economics of large-scale on-orbit
operations.

Len

That's the handwavium part.

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw


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