Cost of launch and laws of physics

A couple of months ago Wired Magazine quoted John Pike as saying,
"It costs $10,000 a pound to get into space, and the reason isn't the
government - it's physics." A lot of people here devoted many postings
to ridiculing this comment. Some were not content to refute the statement
and also questioned Pike's credentials, political ideology, and intellect.

The comment was an off-the-cuff exaggeration, but one interpretation
of it is true enough. Of course there is no physics equation that
produces $10,000 per pound or any other value for the cost of launch.
What is true is that the organization that actually launch things into
space (NASA, Boeing, the Russians, etc.) don't just spend tons of money
on bureaucracy. Rather, they also spend tons of money coping with laws
of physics. It's not like Coca-Cola, which could be 20 times cheaper if
it were just the syrup and no marketing. 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.

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.

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.
So here is the context:

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. During the long climb into orbit,
the atmosphere steadily decreases in density. The Roton starts out at
very low speeds in the high-density atmosphere. As it picks up speed
and climbs higher, the atmosphere thins out. The "dynamic pressure"
(think wind) would actually be lower for the Roton than for many
high-performance aircraft, including fighters.

During reentry, the Roton would encounter a pretty benign environment
as well. The Roton would start out at high speeds, but the atmosphere
would be very thin. As the atmosphere becomes more dense at lower
altitudes, the rotor would slow the vehicle down. Also, the load on
the blades would be rather small because most of the propellant would
have been consumed - meaning more than 90 percent of the overall
weight would be gone. Wind tunnel tests have shown the heating
would be no worse than that experienced by the space shuttle or
other reentry vehicles.

The heating would be "no worse" than that experienced by the space
shuttle? Hmm...
--
/\ Greg Kuperberg (UC Davis)
/ \
\ / Visit the Math ArXiv Front at http://front.math.ucdavis.edu/
\/ * All the math that's fit to e-print *

(Greg Kuperberg) writes:

A couple of months ago Wired Magazine quoted John Pike as saying,
"It costs $10,000 a pound to get into space, and the reason isn't the
government - it's physics." A lot of people here devoted many postings
to ridiculing this comment. Some were not content to refute the statement
and also questioned Pike's credentials, political ideology, and intellect.

John Pike has no qualifications to make this claim. Note that even on
his own, self promoting, web page, he makes no mention of any degrees
or any real experience that would qualify him to make such a claim.

http://www.globalsecurity.org/org/staff/pike.htm

Others on John Pike's staff
(http://www.globalsecurity.org/org/staff/index.html) hold degrees in:

1. Masters Degree (D.E.A.) in Political Studies
2. Bachelors Degree in International Studies (Masters Candidate Security
Policy Studies )
3. Bachelor of Arts degree
4. degree in International Service
5. Ph.D. in chemistry from Lehigh University in 1984 for the study of
tissue lytic proteins produced by the human pathogen Vibrio
vulnificus, a microorganism responsible for a type of "flesh-eating"
disease in those with compromised immune systems
6. Associate of Applied Science degree in Mechanical Engineering
Technology
7. Masters Degree in History

None of these people has a background that would qualify them to make
the statement that Pike made.

The comment was an off-the-cuff exaggeration, but one interpretation
of it is true enough.

I don't think so. There was nothing in the statement that indicated
that he was exaggerating.

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.

Anyone with any qualifications would know that what Gary said is true.
Roton would have been mostly empty tankage. As such, the heating it
experiences on re-entry would be much less than the much more dense
shuttle (which drops its large, empty tank before reaching orbit).
Roton would do much of its decelleration very high in the atmosphere
where the dynamic pressure is low. The shuttle, being very dense,
simply can't. It's apples and oranges to anyone who understands a bit
of the physics (something that Pike clearly does not understand).

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

Greg, it's mostly nothing to do with physics; it's economics. It's more
to do with the low market size right now; which in turn is to do with
the current high cost.

It's catch 22. The price is too high, so practically nobody goes.
Because nobody goes, the costs stay high (development costs don't
amortise away, unit costs stay high, production costs stay high.) It's
not that you don't need 10,000 people to go into space, it's just that
if you only send 4 rockets into space with those 10,000 people, then it
costs 2.7x more than if you send 16 rockets into space with, say, 15,000
people.

Basically, rockets are currently mostly built by hand, one off. That's
expensive. Production lines are cheaper. The Russians use more
production line techniques, and their rockets are about 1/4 the cost of
other people. (It has been very, very frequently suggested that low
wages are the reason for this, but people who have gone to Russia report
that it turns out that that only accounts for some, but not all of the
differences; Russian rockets are 1/2 the cost even allowing for this,
strangely enough the laws of physics are the same in Russia as elsewhere).

Physics definitely has a part to play though; it's just that that isn't
the dominant force that keeps the price high as it is right now.

"Greg Kuperberg" wrote in message
...

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.

Build or design? Design can be costly, but once designed, building is just
bending metal.

Compare how much manpower the Russians spend on producing a Soyuz or Proton
compared to say an American Atlas or Delta.

Then compare the infrastructure required to launch it.

Completely comparing salaries (since that's a tough one to compute) you'll
find if we build rockets the way the Russians do, they'd be cheaper by quite
a bit.



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.

Okay, I imagine that someone will tell me that I'm quoting out of context.
So here is the context:
--
/\ Greg Kuperberg (UC Davis)
/ \
\ / Visit the Math ArXiv Front at http://front.math.ucdavis.edu/
\/ * All the math that's fit to e-print *

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:

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 *

(Greg Kuperberg) wrote:
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.

The destruction of the Columbia makes no such thing clear. Columbia
was not destroyed because the entry was not 'benign', but because it
suffered significant damage to it's protective systems. A bathtub
filled with water at body temperature to a one foot depth is an
extremely benign environment, yet you can still slip, or drown.

That being said, Columbia does have a relatively benign re-entry
environment compared to denser vehicles (like Apollo), but less benign
compared to extremely low density vehicles (like Roton). Speed
matters, as does ballistic coefficient, the exact profile flown, and a
host of other variables.

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".

How 'benign' a reentry environment is varies wildly across the body of
a given vehicle. Note carefully how Apollo varied the thickness of
it's shielding, yet it all was the same high temperature material. On
the other hand, the Shuttle uses a larger variety of material because
the environment is so different across the surfaces of the vehicle.

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.

At that point in the re-entry, the blades are deployed from the body,
then positioned at angle where they are 'dragging' behind the vehicle.
In this position they are in the 'wake' of the vehicle and not exposed
to full re-entry heating.

This position was chosen for multiple reasons; firstly, it provides
'shuttlecock' stability to the vehicle. Secondly, as the blades
autorotate, centripetal force will cause the blades to come down to
their normal operating position gradually. Were the blades deployed
later, they would be forced upward by drag and experience much greater
loads and stresses.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

Greg Kuperberg wrote:
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.

Re-entry vehicles other than ballistic missile RVs have a hot side
and a cooler side. Well, even RVs have a cooler spot on the back,
but it's not very big.

The 'front side' of the shuttle has very high temperature exposed
edges (leading edges, RCC panels) and moderately high temperature
large surface areas (black tiles). The 'back side' of the shuttle
has moderately low to fairly low temperature areas. Some of the
areas are protected by essentially flexible quartz fabric blankets,
and experience no more peak temperature or temperature duration
than is seen cooking a posteak on the barbequeue. The insulation is
required primarily because Aluminum's high temperature tolerance
is terrible; if the upper surfaces were made of steel or titanium
you could get away without insulating them, just making sure that
heat leaking in didn't fry wiring or hydraulics inside, etc.

In the Roton vehicle design, the base reenters first, and has the
high heat loading areas. The hypersonic aerodynamics mean that
the hot high temperature gas flows off with the primary shockwave,
and stays well away from the sides of the vehicle. Though the
environment at the sides of the vehicle, and at the top and out
where the rotors would be, is pretty hot, it's like what you see
on the back side of the shuttle. Not 'melt everything not covered
in RCC, tiles, or ablator' hot; cool enough that inconel and
other high temperature alloys will be fine, at least.


-george william herbert

"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.

"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.