poor man's rocket

Peter Fairbrother wrote:
Actually they would be utterly stupid to spend $100M on the sat. The only
reason why a sat that has a few $100k of functionality can cost $100M is
that the overall mission cost is lower bounded by the launch cost.

Um, no. a good sized chunk of the cost is in the engineering needed
to make it last for years in a hazardous environment. Even with
launch costs drastically reduced, it's not clear how much satellite
costs can fall for commercial birds. (Few of them can tolerate
extended outages, as such outages can cost millions of dollars a day.)

Even if costs fall, and lead time falls, (and the two are not
unrelated), you have the non trivial task of storing the spare, and
you have the time it takes to reach geosync for commo birds.

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:
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Corrections, comments, and additions should be
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discussion.

"Paul E. Black" wrote:

Joann Evans wrote:

Peter Fairbrother wrote:
Remember, we make no such distinctions with aeronautical or maritime
transportation....

We do in postage. I usually do not pay more for invitations, bill
payments, etc. because the US postal system is good enough. Once
in a while I do pay more to have a lower chance of problems (like
when I sent our family's 120-yr old Bible across the county back
to my Aunt).

With postage, you usually pay more for faster delivery times, and/or
confirmed delivery to a specific individual, not an increased certainty
that it will be delivered *at all.* Even at book and magazine bulk
rates, you're making the assumption that it *will* eventually reach the
addressee.

The mail rides the same 'man-rated' planes that you or I do.

I think there would be a market for very high reliability launch
and high reliability launch.

If I couldn't afford a 'high-reliability' launch outright, I'd try to
share a launch with one that's going essentially where I want to go.
Amateur Radio satellites generally get launched like this.

"Derek Lyons" wrote:
Peter Fairbrother wrote:
Actually they would be utterly stupid to spend $100M on the sat. The only
reason why a sat that has a few $100k of functionality can cost $100M is
that the overall mission cost is lower bounded by the launch cost.

Um, no. a good sized chunk of the cost is in the engineering needed
to make it last for years in a hazardous environment. Even with
launch costs drastically reduced, it's not clear how much satellite
costs can fall for commercial birds. (Few of them can tolerate
extended outages, as such outages can cost millions of dollars a day.)

Even if costs fall, and lead time falls, (and the two are not
unrelated), you have the non trivial task of storing the spare, and
you have the time it takes to reach geosync for commo birds.

That's somewhat questionable. Most likely, cheaper launches
and less robust satellites would result in different satellite
designs which allowed them to more easily hand off services to
each other (think about the last time you noticed passing from
one cellular phone cell to another). In that case "spares"
aren't quite the right way to look at it, more like "excess
capacity". And then you just have to worry about having enough
excess capacity to guarantee service until you can launch more
satellites (which, with cheap launchers might not be a long wait).

Even so, there are some pretty fundamental economic reasons
behind short-lifespan capital assets. Not the least of which is
the tax code, which frowns on such things, more or less. An
economists, which I'm not and never plan on being, could
probably tell you about the interplay between asset lifespan
and various other costs. But my gut tells me that lifespans
for expensive capital equipment is almost always best kept at
above several years rather than only a few years or less than a
year.

Now, on the other, other hand, I am unconvinced that cheaper
satellites need necessarily be shorter lifespan satellites.
And I can imagine especially that greater mass bugets and
more frequent full-up design testing (both of which depend on
cheaper launch) could quite easily make up for more expensive
design, construction, and components.


And, on the other, other, other hand! Most of the cost of a
satellite is in the design and testing phase. Motorolla
showed how to build satellites, state of the art satellites,
in production line fashion at fairly low unit cost. In such
cases the unit cost approaches the unit incremental cost
(actual construction labor and component cost) as the
design and testing overhead costs get amortized over much
larger numbers of units. Today with only a few satellites
sold or launched a year those overhead costs make up
sizeable chunks of the unit cost. Now, if a satellite line
is set up for mass production (and that's a big if) then
it's possible to take advantage of low cost yet low
reliability launchers by building more satellites than you
need, knowing that some will not be launched successfully.
Now, the disadvantage of this is that it only really pays
off for bulk satellite purchases, and then it mostly pays
off in the reverse direction (more satellites per dollar,
rather than fewer dollars per satellite, yes, there is a
difference). For a network of satellites this is a no-
brainer (and it is more or less *exactly* what Iridium and
Globalstar did) but for launching a single commsat or even
a few commsats, it's too risky to make sense.



I think that's enough hands for now.

(Karl Gallagher) wrote:
Derek Lyons wrote:
a good sized chunk of the cost is in the engineering needed
to make it last for years in a hazardous environment.

To make it last for years *without* *maintenance*. If we can
get access cheap enough to routinely send up techs to do
preventive and corrective maintenance satellites will get a
lot cheaper. Possibly by an order of magnitude.

For geosynch, that's a long, long stretch away to be cheap enough I
suspect. The core problem isn't CATS, (which is seemingly doable in
the near term), but being able to launch the transtage and capsule the
tech will need to reach GEO. Current CATS thinking is centered around
fairly modest payloads to LEO.

Even so, high reliability will always continue to be a design driver.
Maintenance costs money, as does downtime.

IIRC a cell phone tech telling me that the average tower unit is
designed for a lifetime of 5+ years. In a good sized city with
hundreds of those units installed, that a goodly amount of maintenance
even considering only the units that last their full life without
requiring the services of a tech.

Which brings up another item that drives reliability issues; If a
company only owns a small number of GEO birds, high (and costly)
reliability may still be preferable over the costs of maintaining a
maintenance capability.

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.

"Christopher M. Jones" wrote:
I think that's enough hands for now.

I've run out of fingers to keep track of the hands...

But you pretty much got a synopsis of a summary of a condensed version
of the issues right. It's far more complex than most people think,
and the financial and hardware tradeoffs are interrelated in a variety
of complex ways. (And that's without the additional complexity of
trying to project the costs and other issues into the future.)

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.

"Christopher M. Jones" wrote:
My second point is actually more important with regard to
the satellite industry in the present and near future and
relates to insurance.

There's more in your message I'll address later (how much later, I
dunno, I have a reunion of my submarine crew this weekend), but one I
want to toss out first;

Insurance is *not* a panacea. Even with insurance, a failed launch
(whether rapid disassembly or failure to reach a useful orbit), can
leave you in a lurch. Insurance money in hand can't replace a lost
bird in the short term (modulo mass produced birds). A bird in hand
can't replace a bird in orbit in the short term (modulo launch delay
decreasing). Therefore, even with insurance, a company with few birds
can be caught in a bad corner if one of them fails to launch.

There are no 'loaner cars' in the space business currently or in the
foreseeable future.

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.

toby peers wrote in message
...


I've posted an idea for a peroxide powered turbo-prop vtol spaceplane on
the
halfbakery website at:

http://www.halfbakery.com/idea/prope...rocket_20plane



I've included a link to an aerobatic plane that can fly vertically in
sustained flight (someone else has included a link to a biplane
equivalent),
a link to Glen Olson's pogo page and a link to Armadillo Aerospace but i
couldn't find a link to a self standing, simple explanation of a 'walter
style' peroxide turbine. Does anyone know of a site which I could include
a
link to?

I found a link to a rocket-turbine car. The engine was a gas-generator
powered turbine drive called a turbonique.

http://www.almar.easynet.be/turbonique.htm

Does anyone know if anyone ever tried puting one of these engines in a
plane (either to power a propeller or a ducted fan)?


Toby

Penguinista wrote

Still, a jet powered first stage dropping of ~mach 3 could
make sense.

Been looking at this a bit more, and it seems to me that a jet/rocket first
stage might be even better for a reuseable TSTO.

A back-of-an-envelope design:

Suppose you have a 50 ton OEW (operating empty weight) plus ten tons flyback
fuel piloted jet/rocket "Lifter", and a 60 ton lox/LH2 second stage with a
MR of 4.4. It makes sense to use lox for the first stage rocket as we have
it on-hand, and we'll use "hydrocarbon" as the fuel.

If we take a MR of 2.45 for the lifter rockets, that's 295 tons, and add 45
tons "hydrocarbon" jet fuel for the first stage, giving a MTOW (max take-off
weight) of 340 tons. That gives us 16,000 lb payload to LEO.



The only problem is the dry weight of the lifter. Typically airliners have a
MTOW/OEW of about 2-3 as opposed to our 6.8. Could it be done?

The fuselage is only about half the diameter and half the length of a
comparable jet. The wings can have a higher loading, and we can sneak in a
bit of rocket power for takeoffs. The jet engines can be lighter than normal
(no fans, lower performance and power) and we don't need floors, windows,
loo's, seats etc.


Everything else is well within modern technological limits, I've allowed
good margins and double the usual mass for the second stage engine, so we
can really develop an immediately reuseable engine with a long lifespan. The
lifter rocket engines are a bit unusual, but I won't go into that here, save
to say that they are initially cheap and mostly reuseable, later becoming
totally reuseable.






Second stages come in two types, an unmanned satellite-launch "Cargo" stage
and a manned "Spacebus", both using the same wholly-reuseable engine. They
are both 3.5 m diameter, the Cargo is the usual cylinder and the Spacebus
orbiter is a cylinder with wings that fit into the wings of the lifter. Both
are totally enclosed by the lifter until separation.

The lifter is piloted, and man-rated initially as an experimental vehicle.
We start off just using the unmanned Cargo, giving sat launch income and
paid-for test flights, before developing and flight rating a manned arbiter.

The Cargo stages return the engine and other expensive bits (by using an
ablative heatshield/ parachute, and discarding the empty tanks) so we can
reuse the engines, and use the inspection data to develop our second stage
engine into a really reliable reuseable before risking a manned flight. The
tanks burn up on (separate) re-entry.


It's about as safe as a jet. If the lifter rockets fail, we dump fuel and
land. If an unmanned second stage fails then we lose the sat in the ocean
If a manned second stage fails it returns to base and lands. Even a
catastrophic engine failure need not be fatal, depending on design and
magnitude of catastrophe.


Looking at the flight path,

Stage iMass oMass dVhor Vhor Height
tons tons m/s m/s km

Taxi 340 340 0 250 0 (Earth's rotation)

Lifter jet 340 295 250 500 10
Lifter rocket 295 120 1500 2000 160
Cargo 60 13.6 5800 7800 180



the jets take us to 10 km and ~250 m/s, pretty much at a dawdle. The lifter
rockets start at 10 km high so the bells can be optimised for vacuum
operation, giving better overall isp. They are back on the ground within
hours for the engineers to work on them. No real speed is reached before we
get high, decreasing max q on the Lifter

The Lifter takes us to 160 km with a coast, during which separation occurs
in near-vacuum. The entire second stage is enclosed inside the first stage
until then, so the second stages experience no aerodynamic forces on ascent,
meaning lighter weight, no shroud is needed for Cargo, and a manned second
stage orbiter only has to withstand re-entry forces. Cryogenic insulation
can be in the lifter, not on the Cargo or orbiter.



Required investment would be around $700 million, but there are some WAG's
in there.


--
Peter Fairbrother