Rick - the thing to keep in mind about 747 or Dreamliner development is
that each in its time was a refinement of an existing mature transport
vehicle type. As such, they had to apply a great deal of development
effort/expense to incremental improvements at the steep end of all sorts
of diminishing-returns curves in order to eke out the few percent
performance improvements they required to be economically competitive.
The first SSTO transport able to do the job at all will derive most of
its competitive advantage from a difference in kind. The developers
will not have to pursue every last technical aspect far up the steep
part of the cost/performance curve to be competitive. They will be able
to pick and choose which diminishing-returns curves they must push hard
to fly usefully, and which they can save some development time and money
on, for the initial revenue-service version.
Put another way, DC-3 development costs are a more appropriate yardstick
here. The DC-3 didn't have to be perfect, it just had to fly safely and
reliably with the new all-metal high-power monoplane technologies. DC-3
structure was in fact significantly overbuilt and overweight, as witness
its near-infinite fatigue life.
Would it have made sense to spend significantly more development time
and money to shave DC-3 weights to the competitive standards of ten
years later? No. Being first to be Good Enough mattered far more.
Henry V
On 2/15/2018 1:42 PM, Rick Wills wrote:
Henry
I'll throw my 2 cents in here.
$20B should be an upper limit for spaceplane/launch vehicle development. My
estimate is $14B to $17B. A reusable orbital launch vehicle may or not be an
SSTO but it needs to be 100% reusable. My rational for the estimate is Boeing
spent $1 Billion to develop the 747 with first flight in 1969. Today, that's
roughly $7B. Rough order of magnitude is double Boeing's cost; than add 20%
for cost overruns. I can see why some people might argue $20B to $40B; Boeing
Dreamliner is reported to have cost $30B to develop. However, SpaceX could hit
100% reusable with a reusable upper stage.
On Monday afternoon, I spoke to freshman mechanical and aerospace engineering students at the University of Dayton on the
subject of the Engineering Profession. In my "lessons learned" section, I discussed bias. Yep, we all got them.
As an example, I discussed my bias about what a reusable orbital launch vehicle would like. My long held view was a
reusable launch vehicle would be "aircraft like": wings, landing gear, etc, and of course a pilot. (full
disclosure, I hold a commercial pilot rating and am engineer). In preparing for the talk, I realize this bias when as far
back as my childhood looking at Pratt & Coggins book "By Spaceship to the Moon". It's 1950 technology but
the science is solid for the time. In it, there is a nice drawing of a large winged vehicle, they called it a supply
ship. The vehicle was taking off horizontally with a rocket powered sled. My five year old self looked at that and
thought, "that's neat". I now understand the technical, developmental, political, and financial issues with
these sorts of system configurations but the bias was implanted. Now Space X comes along and shows how recovering an
intact undamaged first stage can return a profit. Biases do die hard, but it's hard to argue with success.
Take Care and Be Safe,
Rick Wills
Still waiting for Buck Rogers
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On ;
Behalf Of Henry Vanderbilt
Sent: Thursday, February 15, 2018 1:54 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: SSTO fuels (was Re: SSTO)
On 2/13/2018 7:14 PM, William Claybaugh wrote:
I have seen that paper. For something as technically (much less
economically) difficult as SSTO it seems a little light: even much
more detailed analysis doesn’t often lead to much confidence that I
ought to recommend dropping $20 or $40 billion on one solution over another.
My two cents worth: If fielding a useful SSTO space transport is costing you
$20 to $40 billion, you're doing something very wrong.
That's the sort of price tag you get by farming it out to the existing cost-plus
government aerospace houses, supervised by an existing high-overhead government
R&D bureaucracy.
At the end of that process you may or may not get a useful space transport, but
lots of people will have had decades of low-stress white-collar job security.
Fine if that's your objective - typically if you're a Congressman and they're
your constituents - if you actually care about building useful space
transportation, not so much.
Done as previously described, build your own private team up doing methodical
risk-reduction then development (as with SpaceX and Blue) it should be perhaps
a tenth of that.
Henry V