Re: Further on "Rockets not carrying fuel."

From: 'Hobbit's' skull (rolf184_at_yahoo.com)
Date: 10/29/04 

Date: Fri, 29 Oct 2004 13:32:32 -0500

"Robert Clark" <rgregoryclark@yahoo.com> wrote in message
news:832ea96d.0410291006.162fb295@posting.google.com...
> During a web search I came upon a news article
> describing a method of using water pressure at the bottom of the sea to
launch
> rockets (1). I had started a discussion last year on sci.astro about the
> possibility of piping the fuel up to a rocket during ascent rather than
> carrying the entire fuel load from the beginning of the trip (2).
> During this discussion, someone raised the possibility of just using the
> momentum of the moving fuel alone to provide the propulsion (3). I wanted
to get
> some input on the feasibility of this idea.
> I wanted to keep the fuel piped up gaseous to save weight. You can keep
the
> density low at high pressure by making the temperature high. See (4) to
> calculate the density and other physical properties of hydrogen based on
> pressure and temperature. For example, at 500 bars and 3000 K, the density
is
> only 4.1 kg/m^3.
> Carbon fibers already exist of sufficient strength to support their own
> weight over 100 km (5). These fibers are also of high melting temperature.
So
> could probably withstand say 3000 k temperatures.
> As for pumping the gas up to 100 km heights at those pressures, I suggest
> some type of "ram pump" (6). However, note that the Space Shuttle already
uses
> pumps for its liquid hydrogen and oxygen capable of hundreds of bars of
> pressure (7).
> Some of the things I would like some feedback on are the feasibility of
> moving gasous hydrogen through a 100km long pipe at 500 bar and 3000 K,
> assuming we have a carbon fiber material that can withstand the
temperatures,
> and perhaps most importantly, what would be the aerodynamical effects of a
100
> km long tube, say .1 meters wide, moving at hypersonic speeds.
>

That was all figured out with the Space Elevator.
 Just use the Elevator to move it up to where your rocket is and load the
fuel on there.
Googleit

Relevant Pages

  • Further on "Rockets not carrying fuel."
    ... carrying the entire fuel load from the beginning of the trip. ... density low at high pressure by making the temperature high. ... Could fuel be pumped up to a rocket accelerating to ... powerful as the shuttle main engines to send the gases up the pipe. ...
    (sci.astro)
  • Further on "Rockets not carrying fuel."
    ... carrying the entire fuel load from the beginning of the trip. ... density low at high pressure by making the temperature high. ... Could fuel be pumped up to a rocket accelerating to ... powerful as the shuttle main engines to send the gases up the pipe. ...
    (sci.space.policy)
  • Further on "Rockets not carrying fuel."
    ... carrying the entire fuel load from the beginning of the trip. ... density low at high pressure by making the temperature high. ... Could fuel be pumped up to a rocket accelerating to ... powerful as the shuttle main engines to send the gases up the pipe. ...
    (sci.physics)
  • Re: Further on "Rockets not carrying fuel."
    ... > carrying the entire fuel load from the beginning of the trip. ... > density low at high pressure by making the temperature high. ... > could probably withstand say 3000 k temperatures. ... Just use the Elevator to move it up to where your rocket is and load the ...
    (sci.physics)
  • Re: Further on "Rockets not carrying fuel."
    ... > carrying the entire fuel load from the beginning of the trip. ... > density low at high pressure by making the temperature high. ... > could probably withstand say 3000 k temperatures. ... Just use the Elevator to move it up to where your rocket is and load the ...
    (sci.space.policy)