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Small, cheap, reusable rocket launcher



 
 
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  #1  
Old July 5th 06, 02:57 PM posted to sci.space.tech
Andrew Nowicki
external usenet poster
 
Posts: 43
Default Small, cheap, reusable rocket launcher

The rocket launchers are not economical because they
are not reusable. When they reenter the atmosphere,
their slender bodies soak up so much heat from the
ambient atmosphere that they burn up. The Space
Shuttle is somewhat reusable, but its slender body
has to be protected with a thermal protection system
that is expensive (because it covers large surface)
and unreliable (because it has to be lightweight despite
its large size). A rocket launcher shaped like a big
conical reentry capsule would be more reusable than the
Space Shuttle because its thermal protection system
would be smaller (because it would cover only the bottom
surface of the cone) and cheaper.

The conventional rocket launchers are shaped like a
pencil to minimize aerodynamic drag during the first
minute of the flight. A cone-shaped rocket launcher
would generate too much drag unless it was slowly lifted
above the dense part of the atmosphere (to the altitude
of about 30 kilometers) with a balloon or a helicopter.
Hydrogen balloons are cheap, but not reusable. Helicopters
are reusable, but they need special engines that can
operate at the altitude of 30 kilometers. There are
three such engines:
1. Hydrogen peroxide monopropellant turbine has simple
design, but the monopropellant is rather expensive
and its catalyst bed can be contaminated with commercial
grade monopropellant.
2. Steamjet engine is described in U.S. patent 6,202,404.
Its most practicable implementation, called mass injection
precompressor cooling (MIPCC) is a turbojet cooled with
copious amounts of water and liquid oxygen. The cooling
enables the turbojet to generate thrust up to the altitude
of about 30 km. More info: http://tinyurl.com/msqra
3. Electric motors are cheap and can operate at the altitude
of 30 km. Their energy source can be either a battery or a
generator standing on the ground. The motors and the
batteries need a cooling system when they operate at high
altitude.
3a.Magnesium hydride battery with Ni catalyst has the highest
energy density (http://www.energyadvocate.com/batts.htm)
but it is not yet mature technology. Li-ion batteries have
energy density of only 534 kJ/kg, but they are very reliable
and reusable. (They provide auxiliary power for my laptop
computer.) The Li-ion batteries can be used as the power
source if used up batteries are discarded during the flight.
It takes about 300 watts of helicopter power to lift 1 kg
of weight. At the beginning of the flight the total weight
of the batteries is about one half of the launcher weight.
During 15 minutes of vertical flight the helicopter reaches
its maximum altitude of 30 km, drops off nearly all its
batteries on parachutes, and finally drops off the launcher.
When the helicopter descends, most of its propellers (rotors)
are used as wind turbines which provide power for the
remaining propellers. The last batteries are used up during
landing.
My laptop batteries cost $418/kg. Assuming payload fraction
of 6 percent and total battery weight of one half the
launcher weight, the batteries cost 418/0.06/2 = $3483 per
kilogram of payload. The capital cost of the batteries may
seem rather high, but the batteries are reusable and very
easy to use.
3b.Aluminum wires linking the motors with a high voltage generator
standing on the ground are expensive and difficult to use.
High voltage generators are available from many sources, for
example: http://www.kato-eng.com/hacgen.html They cost about
$0.1/W. At the payload fraction of 6 percent, the generator
cost is about 0.1*300/0.06 = $5556 per kilogram of payload.
In the absence of the generator, the power is provided by
the grid. The cost of connecting to the grid depends on the
distance; electrical utilities charge between $10,000 and
$50,000 per kilometer of transmission line.
The wires must be reinforced with strong (Zylon) rope and
suspended on balloons so that they do not touch the ground. The
design of such helicopter is similar to the design of airborne
wind turbine generator: http://www.skywindpower.com
The helicopter is vulnerable to lightenings and strong winds,
so it must fly near the equator (away from the jet streams):
http://www.skywindpower.com/ww/page010.htm.

Electric motors powered by batteries are the best choice because
they are cheap, reliable, safe, and easy to use. If the helicopter
lifts the rocket launcher above the dense part of the atmosphere,
the launcher can transport payloads that have low density and large
size, for example large space telescope or large greenhouse. THE
LAUNCHER SCALES DOWN VERY WELL BECAUSE IT IS REUSABLE AND BECAUSE
ITS ATMOSPHERIC DRAG IS NEGLIGABLE. ITS TRUNCATED CONICAL SHAPE
LEAVES PLENTY OF ROOM FOR A VERY LARGE EXHAUST NOZZLE WHICH IMPROVES
THE EXPANSION RATIO AND SPECIFIC IMPULSE. LAST, BUT NOT LEAST, THE
SHAPE OF THE EXHAUST NOZZLE IS OPTIMIZED FOR FLIGHT IN THE VACUUM,
BECAUSE IT IS NOT USED IN THE DENSE ATMOSPHERE. This means that a
little guy can cobble together a little rocket launcher that has high
specific impulse despite its primitive, low-pressure design, and
that he can compete on launch cost with the giants of the industry
(if he can afford the legal expenses). If the launcher has three
stages, only the last stage has to be protected with the expensive
composite called reinforced carbon-carbon. The second stage can be
protected with a thick coating of silicone rubber. The first stage
does not need any thermal protection.
  #2  
Old July 18th 06, 10:29 AM posted to sci.space.tech
Mike Swift
external usenet poster
 
Posts: 8
Default Small, cheap, reusable rocket launcher

In article ,
Andrew Nowicki wrote:

The rocket launchers are not economical because they
are not reusable. When they reenter the atmosphere,
their slender bodies soak up so much heat from the
ambient atmosphere that they burn up. The Space
Shuttle is somewhat reusable, but its slender body
has to be protected with a thermal protection system
that is expensive (because it covers large surface)
and unreliable (because it has to be lightweight despite
its large size). A rocket launcher shaped like a big
conical reentry capsule would be more reusable than the
Space Shuttle because its thermal protection system
would be smaller (because it would cover only the bottom
surface of the cone) and cheaper.

The conventional rocket launchers are shaped like a
pencil to minimize aerodynamic drag during the first
minute of the flight. A cone-shaped rocket launcher
would generate too much drag unless it was slowly lifted
above the dense part of the atmosphere (to the altitude
of about 30 kilometers) with a balloon or a helicopter.
Hydrogen balloons are cheap, but not reusable. Helicopters
are reusable, but they need special engines that can
operate at the altitude of 30 kilometers. There are
three such engines:
1. Hydrogen peroxide monopropellant turbine has simple
design, but the monopropellant is rather expensive
and its catalyst bed can be contaminated with commercial
grade monopropellant.
2. Steamjet engine is described in U.S. patent 6,202,404.
Its most practicable implementation, called mass injection
precompressor cooling (MIPCC) is a turbojet cooled with
copious amounts of water and liquid oxygen. The cooling
enables the turbojet to generate thrust up to the altitude
of about 30 km. More info: http://tinyurl.com/msqra
3. Electric motors are cheap and can operate at the altitude
of 30 km. Their energy source can be either a battery or a
generator standing on the ground. The motors and the
batteries need a cooling system when they operate at high
altitude.
3a.Magnesium hydride battery with Ni catalyst has the highest
energy density (http://www.energyadvocate.com/batts.htm)
but it is not yet mature technology. Li-ion batteries have
energy density of only 534 kJ/kg, but they are very reliable
and reusable. (They provide auxiliary power for my laptop
computer.) The Li-ion batteries can be used as the power
source if used up batteries are discarded during the flight.
It takes about 300 watts of helicopter power to lift 1 kg
of weight. At the beginning of the flight the total weight
of the batteries is about one half of the launcher weight.
During 15 minutes of vertical flight the helicopter reaches
its maximum altitude of 30 km, drops off nearly all its
batteries on parachutes, and finally drops off the launcher.
When the helicopter descends, most of its propellers (rotors)
are used as wind turbines which provide power for the
remaining propellers. The last batteries are used up during
landing.
My laptop batteries cost $418/kg. Assuming payload fraction
of 6 percent and total battery weight of one half the
launcher weight, the batteries cost 418/0.06/2 = $3483 per
kilogram of payload. The capital cost of the batteries may
seem rather high, but the batteries are reusable and very
easy to use.
3b.Aluminum wires linking the motors with a high voltage generator
standing on the ground are expensive and difficult to use.
High voltage generators are available from many sources, for
example: http://www.kato-eng.com/hacgen.html They cost about
$0.1/W. At the payload fraction of 6 percent, the generator
cost is about 0.1*300/0.06 = $5556 per kilogram of payload.
In the absence of the generator, the power is provided by
the grid. The cost of connecting to the grid depends on the
distance; electrical utilities charge between $10,000 and
$50,000 per kilometer of transmission line.
The wires must be reinforced with strong (Zylon) rope and
suspended on balloons so that they do not touch the ground. The
design of such helicopter is similar to the design of airborne
wind turbine generator: http://www.skywindpower.com
The helicopter is vulnerable to lightenings and strong winds,
so it must fly near the equator (away from the jet streams):
http://www.skywindpower.com/ww/page010.htm.

Electric motors powered by batteries are the best choice because
they are cheap, reliable, safe, and easy to use. If the helicopter
lifts the rocket launcher above the dense part of the atmosphere,
the launcher can transport payloads that have low density and large
size, for example large space telescope or large greenhouse. THE
LAUNCHER SCALES DOWN VERY WELL BECAUSE IT IS REUSABLE AND BECAUSE
ITS ATMOSPHERIC DRAG IS NEGLIGABLE. ITS TRUNCATED CONICAL SHAPE
LEAVES PLENTY OF ROOM FOR A VERY LARGE EXHAUST NOZZLE WHICH IMPROVES
THE EXPANSION RATIO AND SPECIFIC IMPULSE. LAST, BUT NOT LEAST, THE
SHAPE OF THE EXHAUST NOZZLE IS OPTIMIZED FOR FLIGHT IN THE VACUUM,
BECAUSE IT IS NOT USED IN THE DENSE ATMOSPHERE. This means that a
little guy can cobble together a little rocket launcher that has high
specific impulse despite its primitive, low-pressure design, and
that he can compete on launch cost with the giants of the industry
(if he can afford the legal expenses). If the launcher has three
stages, only the last stage has to be protected with the expensive
composite called reinforced carbon-carbon. The second stage can be
protected with a thick coating of silicone rubber. The first stage
does not need any thermal protection.


Ideas similar to this have been proposed in the past. The reason you do
not see anyone with money pushing them is that there is at least one
element in the plan that has no physical or economic solution. Until a
solution to that element is found there is no need to even consider any
of the other elements.

In your idea the helicopter seems to me to be one of those difficult
elements. You should lookup information on how lift is generated in
helicopters, and wing theory. Note that you are especially interested
in flight in the very low density air at 30 km. Start with your rocket
weight say 40,000 kg and you assume the helicopter, motors, and wires
etc are made from that miracle material engineers like to specify,
unobtainium. :-) You may find that the blades of the helicopter must be
several hundred meters in length before you add the weight of the weight
of the other items.

Now go hit the books and report back what you find about the rotor
diameter and RPM needed to support the assumed weight of the rocket at
the altitude you pick to start the rocket launch at.

--
Mike Swift

Two things only the people anxiously desire, bread and circuses.
Decimus Junius Juvenalls
  #3  
Old July 18th 06, 10:30 AM posted to sci.space.tech
Joe Strout
external usenet poster
 
Posts: 972
Default Small, cheap, reusable rocket launcher

In article ,
Andrew Nowicki wrote:

The conventional rocket launchers are shaped like a
pencil to minimize aerodynamic drag during the first
minute of the flight. A cone-shaped rocket launcher
would generate too much drag unless it was slowly lifted
above the dense part of the atmosphere (to the altitude
of about 30 kilometers) with a balloon or a helicopter.
Hydrogen balloons are cheap, but not reusable.


But airships (whether filled with hydrogen or helium) are. Big ones can
have a quite impressive lift capacity, too.

Re. helicopters:

3. Electric motors are cheap and can operate at the altitude
of 30 km. Their energy source can be either a battery or a
generator standing on the ground [connected by wires].


Did you consider a power source on the ground beaming power to the
helicopters in the form of lasers or microwaves?

Electric motors powered by batteries are the best choice because
they are cheap, reliable, safe, and easy to use.


It's an interesting idea, though recovering all those batteries
parachuted from 30 km strikes me as a logistical problem, which will
therefore drive up the costs. An airship might work better.

Best,
- Joe
  #4  
Old July 20th 06, 08:29 PM posted to sci.space.tech
[email protected]
external usenet poster
 
Posts: 18
Default Small, cheap, reusable rocket launcher


Mike Swift wrote:


In your idea the helicopter seems to me to be one of those difficult
elements. You should lookup information on how lift is generated in
helicopters, and wing theory. Note that you are especially interested
in flight in the very low density air at 30 km. Start with your rocket
weight say 40,000 kg and you assume the helicopter, motors, and wires
etc are made from that miracle material engineers like to specify,
unobtainium. :-) You may find that the blades of the helicopter must be
several hundred meters in length before you add the weight of the weight
of the other items.

As I understand it, helicopters are unable to rescue people off Mount
Everest, K2 or other mountains. It seems that the Pakistani army has
special helicopters that can go up over 6,000 metres.

  #5  
Old July 26th 06, 09:41 AM posted to sci.space.tech
Andrew Nowicki
external usenet poster
 
Posts: 43
Default Small, cheap, reusable rocket launcher

Joe Strout wrote:

But airships (whether filled with hydrogen or helium) are.
Big ones can have a quite impressive lift capacity, too.


The problem is how to bring the balloon or the airship
back to the earth -- you would have to release lots of
expensive hydrogen. The cost of making hydrogen is about
0.7 $/kg, but the cost of liquefying and transporting hydrogen
from the oil refinery to the user raises the cost to about
3 $/kg. Hydrogen, like chlorine, is a destroyer of the ozone
layer. If the rocket weighs 10 tons, you would spend about
$50,000 on the hydrogen alone. Helium is even more expensive.

Did you consider a power source on the ground beaming power
to the helicopters in the form of lasers or microwaves?


Leik N. Myrabo experimented with this idea some 20 years ago.
It works, and it is not very expensive. The microwave
electronics would cost about $100 per 1kg of the rocket weight.
(Batteries cost about $200 per 1kg of the rocket weight.)
I did not mention microwaves because the safety concerns would
drive up the cost.

The cost of electric motors is only about $30 per 1kg of the
rocket weight.
  #6  
Old July 26th 06, 09:41 AM posted to sci.space.tech
Andrew Nowicki
external usenet poster
 
Posts: 43
Default Small, cheap, reusable rocket launcher

Mike Swift wrote:

Now go hit the books...


The physics, in terms of order of magnitude
estimate, is trivial. If you had been able to
handle high school level physics, you would not
have made this comment.

sci.space.policy is a much better place to ask
high school level questions than sci.space.tech.
  #8  
Old August 12th 06, 10:55 PM posted to sci.space.tech
Joe Strout
external usenet poster
 
Posts: 972
Default Small, cheap, reusable rocket launcher

In article ,
Andrew Nowicki wrote:

Joe Strout wrote:

But airships (whether filled with hydrogen or helium) are.
Big ones can have a quite impressive lift capacity, too.


The problem is how to bring the balloon or the airship
back to the earth -- you would have to release lots of
expensive hydrogen.


Why? Normal airships don't release lifting gas; they compress it, by
inflating internal bladders with air. I don't see why it should be any
different for this application.

Did you consider a power source on the ground beaming power
to the helicopters in the form of lasers or microwaves?


Leik N. Myrabo experimented with this idea some 20 years ago.
It works, and it is not very expensive. The microwave
electronics would cost about $100 per 1kg of the rocket weight.
(Batteries cost about $200 per 1kg of the rocket weight.)
I did not mention microwaves because the safety concerns would
drive up the cost.


But they reduce the logistical issues. I wonder whether the safety
issues can be mitigated by careful selection of the wavelength used.

Best,
- Joe
  #9  
Old August 12th 06, 10:55 PM posted to sci.space.tech
dan
external usenet poster
 
Posts: 1
Default Small, cheap, reusable rocket launcher

Back in the 50's when no one knew if spaceflight was even possible,
several tests were made with sounding rockets launched by balloon at
high altitude. However the payload capability of even very large
balloons declines at extreme altitude, and launching a large balloon is
tricky. Because of the long period climbing to launch altitude
cryogenic propellants were not practical. Ultimately it was not
possible to carry rockets capable of getting into orbit. A similar
problem will occur with rotorcraft.

On the other hand, a fixed-wing aircraft.i.e. the B-70, can indeed be
designed to carry a large payload at high altitude. While a large blunt
cone would have to much drag for external carriage on an aircraft, a
saucer-shaped vehicle could be carried and launched edge first and
re-enter flat side first; this is pretty much what Rutan's SpaceShip
One does with its pivoting tail. This can spread the heating over a
large area as with the Apollo Capsule, reducing thermal loads.

  #10  
Old August 12th 06, 10:56 PM posted to sci.space.tech
Jeff Findley
external usenet poster
 
Posts: 5,012
Default Small, cheap, reusable rocket launcher


"Andrew Nowicki" wrote in message
...
Joe Strout wrote:

But airships (whether filled with hydrogen or helium) are.
Big ones can have a quite impressive lift capacity, too.


The problem is how to bring the balloon or the airship
back to the earth -- you would have to release lots of
expensive hydrogen. The cost of making hydrogen is about
0.7 $/kg, but the cost of liquefying and transporting hydrogen
from the oil refinery to the user raises the cost to about
3 $/kg. Hydrogen, like chlorine, is a destroyer of the ozone
layer. If the rocket weighs 10 tons, you would spend about
$50,000 on the hydrogen alone. Helium is even more expensive.


I'd think it would be cheaper to buy kerosene and build a conventional
LOX/kerosene first stage than it would be to build and operate an airship
big enough to replace said first stage. The airship, after all, is going to
be so huge, it would need some big engines of its own just to maneuver back
to base once it's launch vehicle has been released.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)


 




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