Rockets not carrying fuel.

"Doug Ellison" wrote in message
...

"Robert Clark" wrote in message
om...
From this web page, the weight of the shuttle external tank with the
liquid oxygen and hydrogen is 1.6 million pounds:

EXTERNAL TANK
http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

But the amount of liquid oxygen that is burned is only 2,787 pounds
per second and the amount of hydrogen 465 pounds per second.

Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long. Could fuel be pumped up to a rocket accelerating to
orbital velocity?

I believe it's only possible to pump fluids to a certain height - after
which you just cant push any more

You can always push, but there is a limit to how high you can pull.

Robert Clark wrote:

From this web page, the weight of the shuttle external tank with the
liquid oxygen and hydrogen is 1.6 million pounds:

EXTERNAL TANK
http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

But the amount of liquid oxygen that is burned is only 2,787 pounds
per second and the amount of hydrogen 465 pounds per second.

Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long. Could fuel be pumped up to a rocket accelerating to
orbital velocity?

Intensely stooopid idea. The rocket still lifts most of the fuel,
plus the pipe, plus the ice on the pipe. Friction with the piping
wall prevents flow. Expel your breath, then expel it through a soda
straw. Compare flow rates

What would be the fuel requirements for a rocket that did not carry
its own fuel? Say a rocket with the payload capacity of the shuttle
and with engines of the efficiency of the shuttle main engines?

Why don't you beam a laser at it to blast the air underneath into
plasma and push the thing up? That was deeply supported by NASA
despite the obvious square-cube contradiction.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!

Uncle Al wrote in message ...
Robert Clark wrote:

What would be the fuel requirements for a rocket that did not carry
its own fuel? Say a rocket with the payload capacity of the shuttle
and with engines of the efficiency of the shuttle main engines?

Why don't you beam a laser at it to blast the air underneath into
plasma and push the thing up? That was deeply supported by NASA
despite the obvious square-cube contradiction.

A problem with the Leik Myrabo "light craft" is that the lasers have
to be very powerful to maintain the concentrated energy at the
distance of the spacecraft and to overcome dispersion by the
atmosphere.
If large scale carbon nanotubes do become available it might work to
form a 100km long electrical power cable to power a laser carried on
board the ship. Then that would eliminate the atmospheric dispersion
and attenuation problems.

Riding Laser Beams to Space
By Leonard David
Senior Space Writer
posted: 06:58 am ET
05 July 2000
http://www.space.com/businesstechnol...on_000705.html


Bob Clark

(Robert Clark) wrote in message . com...
[snip]
Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long.

Listen. If you could build a tube that could carry the fuel, why
would you need the shuttle? Why not just climb up the tube?

Could fuel be pumped up to a rocket accelerating to
orbital velocity?

Nope! If you are going to push the fuel into the shuttle at
the speed the shuttle is moving, you've got still the same
energy requirements. You've moved them onto the tube, but
you still have to push the fuel just as hard. So, effectively,
you are climbing up the tube. Once again, what use is the
shuttle in this scenario? Why not just climb up the tube?
Socks

In article ,
Robert Clark wrote:
From this web page, the weight of the shuttle external tank with the
liquid oxygen and hydrogen is 1.6 million pounds:

EXTERNAL TANK
http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

But the amount of liquid oxygen that is burned is only 2,787 pounds
per second and the amount of hydrogen 465 pounds per second.

Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long. Could fuel be pumped up to a rocket accelerating to
orbital velocity?
What would be the fuel requirements for a rocket that did not carry
its own fuel? Say a rocket with the payload capacity of the shuttle
and with engines of the efficiency of the shuttle main engines?



Bob Clark

Practical considerations aside, I think it's a neat idea.

--
"A good plan executed right now is far better than a perfect plan
executed next week."
-Gen. George S. Patton

In article , (Gregory L. Hansen) writes:
In article ,
Robert Clark wrote:
From this web page, the weight of the shuttle external tank with the
liquid oxygen and hydrogen is 1.6 million pounds:

EXTERNAL TANK
http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

But the amount of liquid oxygen that is burned is only 2,787 pounds
per second and the amount of hydrogen 465 pounds per second.

Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long. Could fuel be pumped up to a rocket accelerating to
orbital velocity?
What would be the fuel requirements for a rocket that did not carry
its own fuel? Say a rocket with the payload capacity of the shuttle
and with engines of the efficiency of the shuttle main engines?



Bob Clark

Practical considerations aside, I think it's a neat idea.

Practical considerations aside, I think that teleportation is a neater
idea:-)

Mati Meron | "When you argue with a fool,
| chances are he is doing just the same"

In article ,
wrote:
In article ,
(Gregory L. Hansen) writes:
In article ,
Robert Clark wrote:
From this web page, the weight of the shuttle external tank with the
liquid oxygen and hydrogen is 1.6 million pounds:

EXTERNAL TANK
http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

But the amount of liquid oxygen that is burned is only 2,787 pounds
per second and the amount of hydrogen 465 pounds per second.

Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long. Could fuel be pumped up to a rocket accelerating to
orbital velocity?
What would be the fuel requirements for a rocket that did not carry
its own fuel? Say a rocket with the payload capacity of the shuttle
and with engines of the efficiency of the shuttle main engines?



Bob Clark

Practical considerations aside, I think it's a neat idea.

Practical considerations aside, I think that teleportation is a neater
idea:-)

Nah... the hose to the gas tank has sort of a Jules Verne quality to it.
It's cute, it's quaint. It has sort of the same quality as a torpedo
powered by an internal combustion engine.


--
"A good plan executed right now is far better than a perfect plan
executed next week."
-Gen. George S. Patton

(Robert Clark) wrote:
From this web page, the weight of the shuttle external tank with the
liquid oxygen and hydrogen is 1.6 million pounds:

EXTERNAL TANK
http://science.ksc.nasa.gov/shuttle/...ewsref/et.html

But the amount of liquid oxygen that is burned is only 2,787 pounds
per second and the amount of hydrogen 465 pounds per second.

Nanotube productions methods are advancing quickly. Suppose it is
possible to make a fuel line of carbon nanotube material hundreds of
kilometers long. Could fuel be pumped up to a rocket accelerating to
orbital velocity?
What would be the fuel requirements for a rocket that did not carry
its own fuel? Say a rocket with the payload capacity of the shuttle
and with engines of the efficiency of the shuttle main engines?

In addition to the problems others have mentioned, if you somehow
did manage to pump fuel up to the shuttle fast enough through a hose of
manageable size (assuming that you could keep the hose from getting burned
up by the exhaust and air friction), pretty soon you will get to the point
at which the kinetic energy of the fuel exceeds any chemical energy it could
possibly have (same reason as why you need to carry so much chemical fuel for
each little bit of payload in the first place). At this point, you might as
well select what you send up the hose for optimum pumping characteristics and
never mind about its fuel characteristics, because at this point the shuttle
has become an Orbital Water Wiggle(tm).

--
Lucius Chiaraviglio
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