Cost of launch and laws of physics

On Wed, 06 Aug 2003 00:24:36 GMT, in a place far, far away, "Greg D.
Moore \(Strider\)" made the phosphor on my
monitor glow in such a way as to indicate that:


The flip side of this is that many of the CATS/RLV/X-Prize believers
don't seem to take the laws of physics very seriously. For example,
another Wired article quotes Gary Hudson as follows: "That leaves the most
frequently asked question about the Roton: wouldn't the rotor blades burn
off in the atmosphere? The remarkable - and counterintuitive - answer
is No." Given what happened to the space shuttle Columbia,
that is a fair question. Just calling the answer counterintuitive and
remarkable doesn't make it right.


No, but it IS right. The answer IS counterintuitive and remarkable. I
don't see where you argument is other than he didn't explain WHY it's
counterintuitive and remarkable. Which, given the context, he appears to
have done.

So, I have no clue what point you're making here.

Sadly, I suspect that he doesn't either. He should perhaps expand his
expertise beyond mathematics before embarassing himself further.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

"Greg Kuperberg" wrote:
Think how much harder it is to build a car that goes 120 mph than a
bicycle that goes 12 mph. Now think how much harder it is build a jet
that goes 1,200 mph than a car. Now take it one step further and you've
got the difficulty of manned spaceflight. Of course doing any of these
in expendable, unmanned form is much easier, which is part of the reason
that most space rockets are expendable and unmanned.

Pffft. It costs next to nothing to build a car that can go
120 mph, probably only about the same cost as a decent
bicycle (few hundred dollars). It costs a lot of money to
make a nice car though, and by the standards of "physics",
all modern cars are nice. A simple engine powered vehicle
with 4 wheels is a far cry from today's automobiles. And,
for example, building a model-T type car (let alone
something simpler) would be much cheaper than any car now on
the market. When was the last time you saw a new car
without an upholstered interior, power brakes, power
steering, a windshield, windows, full suspension, a heater,
a speedometer, headlights, signaling lights, brake lights,
an automatic starter, a battery, or an alternator? Not
recently I'd bet. But none of those things are strictly
required to go 120 mph or even 40 mph. Cars are cheap
now because we've had so much experience building them
and we know how to do it very well, and also because the
market has grown so large that overhead costs in the
billions (a typical cost range for design and production
line setup for a modern car) are amortized to near nothing
per car among so many buyers. If we'd started off in the
late 1800s thinking that the only way to make a car was to
festoon it with fancy, expensive googaws then we'd have
never had the cost breakthrough that led to automobile
ownership being widespread and fairly inexpensive.

The same thing is the case for spaceflight, I believe.
We have these one of a kind, custom built luxury vehicles
which are too expensive to open up the spaceflight market
much (manned or unmanned). What we need is a simple
model-T that does the job and is cheap, though not
necessarily the finest of its class. But, once lots of
people or companies buy the model-T and use it that will
create the more broad based market which will be capable
of pushing development at a much faster pace than the
hand-buil, custom model production lines can, and thus we
will end up with better, less expensive launch vehicles
in the long run, due to expansion of the market.

As I said, it happened with automobiles; it also happened
with computers and audio/video electronics, and much
else.

"Rand Simberg" wrote in message
...

Launching a rocket into orbit
takes talented engineers, special materials, and painstaking inspections,
because usefully travelling at 12,000 miles an hour is really hard.

Which isn't what drives the high cost.

Think how much harder it is to build a car that goes 120 mph than a
bicycle that goes 12 mph. Now think how much harder it is build a jet
that goes 1,200 mph than a car. Now take it one step further and you've
got the difficulty of manned spaceflight.

Funny thing is, it doesn't cost much more to to fly across country
than it does to drive, especially when one takes the full costs
(depreciation, etc.) into account.

That's a bit of an apples and oranges comparison though. It doesn't cost
more more to fly across the country with other people to help with the cost
than it does to drive yourself.

If you paid to be the only passenger on an entire 737 and had to made

Physics might account for one order of magnitude difference between
air transport costs and space transport costs, but not two, or three,
which is where it is right now.

Well, no surprise I disagree with you here.

But, what interests me more is the basis you use for this claim?

The challenge is getting it down to where the only difference *is*
accountable to the difference in velocity (which would make it
affordable for many things that people here want to do). That's not a
problem that's solved by changing laws of physics--just changing
public perception and building markets and businesses.

The flip side of this is that many of the CATS/RLV/X-Prize believers
don't seem to take the laws of physics very seriously. For example,
another Wired article quotes Gary Hudson as follows: "That leaves the
most
frequently asked question about the Roton: wouldn't the rotor blades burn
off in the atmosphere? The remarkable - and counterintuitive - answer
is No." Given what happened to the space shuttle Columbia,
that is a fair question. Just calling the answer counterintuitive and
remarkable doesn't make it right.

Okay, I imagine that someone will tell me that I'm quoting out of
context.

No, just that you don't seem to understand the physics. Heating is a
function of many things besides velocity per se (e.g., physical
loading).

I was at a talk by an ESA physicist who's got money to study "alternative"
re-entry dynamics - he's in favour of big slow re-entry.

"Christopher M. Jones" wrote in message
...


The same thing is the case for spaceflight, I believe.
We have these one of a kind, custom built luxury vehicles
which are too expensive to open up the spaceflight market
much (manned or unmanned). What we need is a simple
model-T that does the job and is cheap, though not
necessarily the finest of its class. But, once lots of
people or companies buy the model-T and use it that will
create the more broad based market which will be capable
of pushing development at a much faster pace than the
hand-buil, custom model production lines can, and thus we
will end up with better, less expensive launch vehicles
in the long run, due to expansion of the market.

As I said, it happened with automobiles; it also happened
with computers and audio/video electronics, and much
else.

But not with supersonic passenger aircraft. :-/

Low costs and mass production are fine if the market exists, I'm personally
very dubious about the space tourism angle and without that the market
opportunities for mass production are relatively limited.

I recently flew Concorde which was full, but mostly of aviation enthusiasts
like me who had had a chance at a low cost ticket, all of us were pretty
much at the limit of what our partners would allow us to spend on a one-off
treat. Still, the low cost approach seems to have worked with Concorde, it
is fully booked pretty much until they stop flying it.

That's not to say that I think Virgin could run it profitably.

I got some incredible pictures out of the window at 58,000 feet which,
sadly, probably about as high as I expect to ever get to fly.

"Greg Kuperberg" wrote in message
...
snip

Caution - unobtainum can degenerate rapidly and unexpectedly into
costoverunium when exposed to the engineering staff.

-kert

Kaido Kert wrote:

Oh i forgot to credit the author of this quote, Mark Goll, who has done some
excellent writing on the launch cost vs. physics subject.
http://web.wt.net/~markgoll/rse0.htm

A short example:

For this analysis I have used the cost and performance specs for the Space

Shuttle Main Engine, NASA's pride and joy, and used on the new Boeing EELV
Delta IV, as the comparison to a very simple pressure fed booster. Costing
about $140 million and weighting 7000 pounds, it produces an ISP of 363 at
lift off.

The SSME is not used on the Delta IV.

Paul

On Wed, 6 Aug 2003 08:51:00 +0000 (UTC), in a place far, far away,
"Dave" made the phosphor on my monitor
glow in such a way as to indicate that:

Physics might account for one order of magnitude difference between
air transport costs and space transport costs, but not two, or three,
which is where it is right now.

Well, no surprise I disagree with you here.

But, what interests me more is the basis you use for this claim?

Any number of studies performed for both NASA and the Air Force. Most
of the current high cost is due to low utilization rates and
diseconomies of scale, not "physics."

As you pointed out yourself, if I chartered a 737 for myself, the cost
for my ticket would go up two orders of magnitude. No change in
physics.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

In article ,
Greg D. Moore \(Strider\) wrote:
Obviously the driver for flight costs is NOT per/mile.

Yes, obviously. Obviously the driver for the cost of supersonic
flight is *velocity*. Which is why it is ludicrous to argue cost "per
transcontinental trip", as if transcontinental relocation, and not
velocity, should drive flight cost.

This is just restating that rocket companies spend money to cope with
laws of physics, in this case very high velocities. I previously implied
a reference velocity of 12,000 mph, but that is an understatement: LEO
orbital velocity is actually 18,000 mph. A space rocket is to a Mach
3 jet as a Mach 3 jet is to a 180 mph race car, or as a race car is to
a 18 mph bicycle.
--
/\ Greg Kuperberg (UC Davis)
/ \
\ / Visit the Math ArXiv Front at http://front.math.ucdavis.edu/
\/ * All the math that's fit to e-print *

In article ,
Greg D. Moore \(Strider\) wrote:
"That leaves the most frequently asked question about the Roton:
wouldn't the rotor blades burn off in the atmosphere? The remarkable
- and counterintuitive - answer is No." Given what happened to the
space shuttle Columbia, that is a fair question. Just calling the
answer counterintuitive and remarkable doesn't make it right.
No, but it IS right. The answer IS counterintuitive and remarkable. I
don't see where you argument is other than he didn't explain WHY it's
counterintuitive and remarkable. Which, given the context, he appears to
have done.

What he said in context was, first, that re-entry would be a "pretty
benign" environment, and second, that it would be "no worse" than what the
shuttle experiences. But as the destruction of STS-107 makes clear, the
shuttle's environment during re-entry is not remotely benign. People in
this thread said something rather different from the Hudson quote:
that the Roton blades would encounter an environment which is much more
benign than shuttle re-entry, not "no worse".

Now STS-107 broke apart at 210,000 feet moving at Mach 18. How fast is
the Roton supposed to go at that altitude, and what are the helicopter
blades supposed to do then? If they are retracted entirely, at what
altitude and velocity are they supposed to deploy? Taking the laws
of physics seriously requires clear answers to questions like this.
Even answers to within a factor of 2 would be a start.
--
/\ Greg Kuperberg (UC Davis)
/ \
\ / Visit the Math ArXiv Front at http://front.math.ucdavis.edu/
\/ * All the math that's fit to e-print *

"Dave" :

But not with supersonic passenger aircraft. :-/

Low costs and mass production are fine if the market exists, I'm personally
very dubious about the space tourism angle and without that the market
opportunities for mass production are relatively limited.

I recently flew Concorde which was full, but mostly of aviation enthusiasts
like me who had had a chance at a low cost ticket, all of us were pretty
much at the limit of what our partners would allow us to spend on a one-off
treat. Still, the low cost approach seems to have worked with Concorde, it
is fully booked pretty much until they stop flying it.

That's not to say that I think Virgin could run it profitably.

I got some incredible pictures out of the window at 58,000 feet which,
sadly, probably about as high as I expect to ever get to fly.

Have you looked at the stupid limits that the Concorde had to follow.

No high speed overland flights for example can double the flight time and
remove the first reason to use a supersonic transport not to mention adds
more wear and tear per flight and more fuel costs.

No large upscaling of the electronics used, atleast 50% of the electronic was
of 1960-70's design. Yes it worked but there is a lot of added weight
(minor) and servicing olded electronic gets more expensive over time (major).

Limit airports, for reasons not clear to me a number of people NIMBY
attitudes blocked the SST landing in thier area, if you don't have a
destination open you can't fly people there.

Earl Colby Pottinger

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