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Space access through pumping fuel or reaction mass up a long pipeline.

  1. Apr 17, 2005 #1
    Hello. The contributors to this forum seem pretty knowledgeable so I would like some feedback on the idea proposed in this post to sci.astro:

    Newsgroups: sci.astro, sci.physics, sci.mech.fluids, sci.engr.mech,
    From: "Robert Clark" <rgregorycl...@yahoo.com>
    Date: 28 Mar 2005 12:52:00 -0800
    Subject: "Rockets not carrying fuel" and the space tower.

    The idea is to pump the fuel or reaction mass up to a rocket rather than carrying it all with the rocket.
    If the mass of the pipeline had to be supported by the thrust from an engine on the rocket at the top of the pipeline, this would require quite a large amount of thrust. So a key facet of the proposal is to have exhaust vents along the entire length of the pipeline that would support each section of the pipeline.

    Thank You,

    Bob Clark
  2. jcsd
  3. Apr 17, 2005 #2
    Wouldn't you require energy to pump the fuel upto the rocket?

    How far would you be able to take the cable? Not very far.

    How will you manage the high pumping speed required?
  4. Apr 17, 2005 #3


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    Thanks Bob for being so kind. It is for that reason that people in this forum try to answer practical issues and not such dreams of imagination. It hasn't got any engineering base and it is only science fiction.

    I have another possibility. Why not build a serie of 500 oil stations till the stratosphere? Thus the rocket will open the reservoir pipe to recharge the fuel with a pipeline each time it passes in front of one oil station. The astronaut would also get out the rocket and pay the bill.
  5. Apr 17, 2005 #4
    Good question. There are pumps that can pump water arbitrarily high by just using the power of flowing water (no external energy input required):

    Contents for the pulser pump section of Gaiatech.
    http://members.tripod.com/~nxt [Broken] wave/gaiatech/pulser/index.htm

    Designing a Hydraulic Ram Pump.

    These pumps use the momentum of a large amount of water falling a short distance to pump a small amount of water a large distance. There are some ram pumps in commercial use that can pump 200 times higher than the fall distance of the water. Then you would locate the pipeline near a source of a large amount of flowing water such as a river or stream. By using the high pressures produced by these pumps you can also pump gases instead of liquid, which is probably how you want to implement the idea.

    There are also electrical or diesel powered pumps that can pump at the high pressures required:

    Air Driven Liquid Pumps.
    "Haskel air driven pumps offer many advantages over conventional
    electrical driven units as follows:
    Ability to stall at any predetermined pressure and hold this fixed
    pressure without consuming power or generating heat.
    No heat, flame or spark risk.
    Infinitely variable cycling speed output.
    Up to 100,000 psi (7,000 bar) pressure capability with special units to
    150,000 psi (10,000 bar)."
    http://www.flw.com/haskel/1.ht*m [Broken]

    High Pressure Pumps
    "The FC SERIESTM pumps are available for pressures from 10,000 to
    200,000 psi, and 10 to 200 hp."
    http://www.hydropac.com/HTML/F*Cseries.html [Broken]

    Böhler High-Pressure Technology: pumps for tough situations.
    "Apart from these high-pressure and ultra high-pressure pumps with a
    maximum pressure of 10,000 bar, the company, in the Austrian province
    of Styria, also manufactures tube reactors, coolers and valves for
    high-pressure and ultra high-pressure applications in the chemical
    process engineering sector."
    http://www.parker.waaps.com/li*t_page.php?page=743&id=99 [Broken]

    These could easily be scaled to provide 100's of liters per second
    rather than the liters per minute they now provide. (Or you could use a
    whole lot of the little ones.)
    For a liquid at least, you could get the required extra pressure out
    at the top of the tube by adding this amount to the pressure provided
    by the pumps. So if 100,000 psi on the ground gave you the liquid
    reaching the top of the tube, 106,000 psi on the ground gives you the
    liquid at 6000 psi reaching the top of the tube.

    Bob Clark
    Last edited by a moderator: May 2, 2017
  6. Apr 17, 2005 #5
    The way you show an idea is unfeasible is by providing the numbers for it.
    Just stating an idea is impossible without investigating the principles behind it is what led to embarrassing quotes like this:


    BTW, in one implementation of the proposal the pipeline or tower would stay permanently in place when supplied by a continuosly flowing supply of water as from a river. In that case you could have way stations for recreation or scientific study.

    Bob Clark
  7. Apr 17, 2005 #6


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    Great. Another crack-pot. How ironic that not a single link of yours provided actually works.

    - I did find the Haskel site. You present pumps that have very high output pressure capabilities and very low flowrate capacity. What is your point. How long would it take to pump a rocket full's worth of fuel, LOx or what have you at 3 GPM? Have you the intent to scale these up to somehow get more flow? How much energy then will be involved to compress the amount of air to drive these pumps. No data presented by you. Just a pressure number.

    - The FC series pumps you reference are used in non continuous operations that like pressing operations, formings, injection moldings etc..., Once again, requiring low, non continuous flow and high pressures. But again, you state a really high pressure number. That must mean something...

    You say that these pumps could be "adapted" like you just wave a magic wand, to provide 100's of L/s. How? Please enlighten us.

    That's where you're wrong. You are the one that has to prove that it is feasable. Tell me, what is the expected pressure drop going to be for a single pipeline of that length (for any fluid or gas)? How does one propose supporting a pipeline that would extend to that height? How would one assemble it? How economically feasable is it? What if a leak formed in the pipeline? How would this be protected from the elements? How would it be maintained? What will this pipeline be made out of? Should I keep going? I bet you can not answer one of these questions with pure engineering numbers to support your theory.

    Your post reeks of basic crack-pot methodology: Present an insane idea. Post multiple links with information you don't understand hoping to overwhelm the people into supporting you.

    I have a challenge for you. You decide what it will be made out of then figure out just how massive it would have to be to support it's own weight, not taking into account wind loadings and other details.
    Last edited: Apr 17, 2005
  8. Apr 17, 2005 #7


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    Enormous, Excellent sentence. You deserve an award, an Oscar or so. Congratulations. :approve: :biggrin:
  9. Apr 17, 2005 #8


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    But how about looking at it the other way: the way you show an idea is feasible is by providing the numbers for it.

    What you have gotten here is the gut reaction of a number of practicing engineers. Could their gut reactions be wrong? Sure, but it'll take some real engineering to convince them (us). Have you (or anyone else looking into this idea) actually done any calculations to determine its feasiblity?

    If you search this site, you'll actually find that we have discussed this idea in the past. It has two independent, but equally fatal flaws: first, there is no such pump that can do what is required. Sure, you can pump as high as you wish, given enough pumping stations along the way. But how many pumps and how much energy would that require? (A: too much to make it worth doing). Second, how do you build a pipeline/structure 300 miles high? Its far beyond existing technology.

    We have a low tolerance for crackpottery here, RGClark - this discussion needs to be scientific if its going to continue.
  10. Apr 17, 2005 #9
    Alright here are the corrected links:

    Contents for the pulser pump section of Gaiatech.

    This board strangely put asterisks in others:

    Air Driven Liquid Pumps.
    http://www.flw.com/haskel/1.htm [Broken]

    http://www.hydropac.com/HTML/F*Cseries.html [Broken]

    Böhler High-Pressure Technology: pumps for tough situations.
    http://www.parker.waaps.com/li*t_page.php?page=743&id=99 [Broken]

    These are pumps that require extra energy such electrical power or diesel power to operate. The very highest pressure ones provide flow rates on the order of liters per minute. The design of these pumps is quite simple, little more than that used in a hydraulic lift. They are used for example to create high velocity waterjets for cutting parts. They would scale according to size just as easily as hydraulic lifts according to size from lifting cars in auto shops to lifting 70 ton locomotives. And as I said you could combine alot of the already existing ones to provide as much fluid delivered as you needed.
    However, as I said the overwhelmingly easiest way to do it would be just to use a pulser pump or ram pump that does not need an external source of power, just a source of flowing water. There are commercial ram pumps that can pump 200 times the fall height of the water. So to pump to 100 km height you would a water flow that fell 500 meters. Note these pumps could already pump to the required height. The amount delivered at the top of the tube for these pumps would be small compared to the amount flowing into the tube but they would demonstrate the feasibility of the method. Here's an example of one that gives the water delivery rate for different heights:

    Glockemann Pump Specifications.

    The pressure numbers I quoted were because of the pressure required to raise water to the height of 100km, ca. 140,000 psi. But this is for water, quite likely you want to use gases because they are much lighter and therefore the required pressures would be much less.

    Bob Clark

    Last edited by a moderator: May 2, 2017
  11. Apr 17, 2005 #10
    I have no idea why the board puts asterisks in some links and not in others. The only thing I can think of to find these pages is to do a Google search on their titles with the quotation marks:

    "Contents for the pulser pump section of Gaiatech"

    "Air Driven Liquid Pumps"


    "Böhler High-Pressure Technology: pumps for tough situations"

    "Glockemann Pump Specifications"

    Bob Clark
    Last edited by a moderator: May 2, 2017
  12. Apr 17, 2005 #11
    Well, I don't agree here. We DO already have pumps that can pump that high, viz. the ones I cited. The ones that exist now would only deliver small amounts to that height, perhaps liters per minute. But they would demonstrate the feasibility of the method.
    The VERY key aspect of this proposal is that the weight of the tube/pipeline would be supported by the thrust from the exhaust vents along its entire length.
    I would like to see the discussion previously held on this topic on this board if you have the link or the date range it occurred.

    Bob Clark
    Last edited: Apr 17, 2005
  13. Apr 17, 2005 #12


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    RGClark, none of what you just posted is really relevent: none of it addresses the two dealbreaker issues I mentioned.

    For past threads, space elevators and carbon nanotubes are discussed HERE and the pipeline idea is addressed briefly.

    HERE is a thread about a pipeline to orbit, specifically.
  14. Apr 18, 2005 #13
    Thanks for the links. I'll take a look at those. From an initial perusal it looks like they want pumping stations along the way. I'm suggesting all the pumping power stay on the ground to save weight.
    The height that an incompressible liquid can be pumped is purely a matter of pressure; it scales linearly with height. For water the pressure requirement is about 1 bar for every 10 meters. So to get to 100,000 meters you need 10,000 bar, about 147,000 psi. Let's call it 150,000 psi.
    Pumps that can pump at this pressure and above are already in commercial use. Take a look at this companies page of specifications:

    FC SERIESTM High Pressure Pumps Specifications.

    The amount pumped for these is in the liter per minute range, but this is enough to demonstrate the concept.
    Pipelines longer than 100 km already exist of course. The Alaskan pipeline is over a 1000 km long. To produce the pipeline you could extrude the tube continuously or weld together separate sections.
    For getting the tube into the air, the key aspect of this proposal is that exhaust vents are provided along the entire length that produce directional thrust sufficient to raise each portion of the tube into the air.

    Bob Clark
  15. Apr 18, 2005 #14


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    Ok, let's do some number with such pumps. Assume you have to elevate LOx ([tex]\rho_o=1140 kg/m^3[/tex] to a height of [tex] H=100 km[/tex], with a mass flow of 200 Kg/s. Thus, the power required for pumping is the diference of stagnation entalphy, supposing you are pumping from a reservoir of pressure [tex]P_o[/tex]. Also I neglect compressibility assuming a low Mach Number, and I neglect too kinetic energy at the pump intake. If the pipeline has a radius of 25 cm:

    [tex] W=\dot m(h_f-h_o)=\dot m (P_o/\rho_o +g H+v^2/2-P_o/\rho_o)\sim 200(9.8\cdot 100000)\sim 200 MW [/tex]

    First of all, you'll need a medium power gas turbine in order to pump the oxidizer. The cost of pumping (recall I have neglected friction and pressure looses) would be a bit high. In order to maintain the LOx liquid, there will have to cool the pipeline. Don't forget that pumping liquid is more cheap than pumping a gas. So that a cost of coolant must be added.
  16. Apr 18, 2005 #15
    Structural issues aside, pumps and space elevators are among the most efficient methods of getting mass to orbit on a W/kg basis.

    Clausius, you forgot to account for a variation in g.

    Your equation is also missing a few constants.

    Also your assumptions are inconsistent with your equation. If you assumed a pipe diameter, neglected compressibility and the kinetic energy at the pump intake, you can neglect the KE at the pump outlet. These 'follow' each other.

    Really, it looks like you're making a straightforward calculation too complex. If you assume equal end states for a first approximation, it should simply be:
    [tex]P = \int_{r=h1}^{r=h2} m g(r) h dr[/tex]

    I don't support crackpot science, but if you're going to correct him - I'm not saying his idea is/is not crackpot either - at least do it correctly. No pot calling the kettle black please. Also I think some posters could cut down on the sarcasm and be a bit less harsh. Being a frequent poster, PF guru of the year and science advisor means you should set an example in your responses...your job isn't to show people how sarcastic/funny you can be.

    Last edited: Apr 18, 2005
  17. Apr 18, 2005 #16


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    So, do you have a material capable of withstanding several hundred thousand psi of pressure? Either you deal with the column supporting itself or you deal with the massive pressure. Either way, you need to deal with the fact that the pipe needs to be 25,000 miles high (you have to go to geostationary orbit).
    Well, perhaps I missed it: which of those pumps has a rated pump head of 25,000 miles?

    Like I said: you haven't addressed either issue at all. Just saying it can work is not the same as showing it.
    Statements like that make me wonder if you're even serious here. Show you're serious: You tell me what the key difference is between the Alaska pipeline and the one you propose (the difference is obvious and already mentioned) - and then tell me how you think you could overcome it. Otherwise, this thread needs to end.
    Last edited: Apr 18, 2005
  18. Apr 18, 2005 #17


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    OK. I may have been in a bit of a snit when I last posted, so I will apologize for a lack of professionalism in my previous post. I tend to react negatively to persons that present 'ideas' and then leave it to the underlings to actually figure out how to implement the idea realistically. I deal with it on a daily basis.

    That may be true. Along the same vein, warp speed is the most efficient means of interstellar travel. Do I need to elaborate on the huge leap you took in the first three words of your sentence? A w/kg basis is only one measure of efficiency. Also, can you really call it efficient if the means do not exist yet? If an idea is not manufacturable, I would say it is the most inefficient idea of all. There are many more aspects that need to be considered.

    From personal experience I can see the pumping issue as being the easiest of all of the hurdles to overcome (and easy it is not by a long shot). The list of priorities is, as I see it, are:

    1) How would the pipeline be assembled (i.e. technique)?
    2) How would it be supported?
    3) What material would it be made out of?
    4) How would it be protected/maintained?
    5) What would be done in the event of a failure?
    6) What is the cost?

    I have yet to see anyone give any kind of hard facts to back up their theoretical ideas in these areas. I would lay dollars to doughnuts that the cost to attempt to build this pipeline would cost more than 100 space shuttle launches in today's dollars.

    - Continuously extrude 300 miles of pipe?
    - If by welded are you infering that the pipe be made out of a metal?
    - The vents are meant to get the pipe up into position only or they will keep it there as well?
    - How would one control these vents?
  19. Apr 18, 2005 #18


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    I had no idea how high outer space was, but I figured roughly 55 miles. The approximate was close in that a pump would be needed to produce 150,000 psi to pump liquid (S ~ 1.0) that high. However, this would be at 0 flow. In order to produce any reasonable kind of flow, the pressure needed would be substantially higher. In addition to this, 200 ksi is quite a bit of pressure. Assuming a 2' pipe (need to be somewhat big to get higher flows) the thickness of the pipe would need to be at least 40" thick. Now we have massive weight problems in that we have 50 miles of 64" pipe, most of which is solid steel.

    It's a good idea in theory, but as Homer says, "In theory communism should work."
  20. Apr 18, 2005 #19


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    At least I am exposed to this kind of comments like yours, for being PF Eng. gurú. On the other hand you have just come out of nobody knows, by the way saying stupidities like this:

    :confused: What are you? A phisicist?, or an engineer?. I have never taken into account "g" variations unless I am in my physics class. Don't worry, any engineer takes it into account, at least for doing a simple number.

    Sure. It was only an approximation. This comes to demonstrate you are NOT an engineer, or you are a very bad engineer. The difference between an engineer and a guy non engineer is the art of giving approximations to complex problems when examining them at first sight. An engineer MUST know a first approximation in order to reject a project, instead of making ridiculous integrals like that. I assure you very few active professional engineers would know how to do an integral, but they'll know if a project is worthy or not merely looking for some simple numbers. Now we all know you don't know nothing of the art of the engineering.

    Not quite. The kinetic energy behind a compressor is not neglectable at all, in fact it is less neglectable than the kinetic energy just in front of it. This comes to demonstrate you don't know how a compressor works. The transference of stagnation enthalpy to flow increases absolute flow velocity. Read a pair of turbomachinery books before saying nonsenses.

    You are a crackpot by yourself, so maybe you don't support yourself. My example is accurate enough, and gives a number which is below the real value. So the reality is more crude.

    Go home, read some books, and return.
  21. Apr 18, 2005 #20


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    Hey there, haven't been here for a while,

    Couldn't take the time to read the whole thread. Anyway, had an idea once along the lines of what's proposed here. The idea was to place airships or just large balloons along the launch path of a rocket at equak distances - say every 2 or 3 miles. These will support the weight of hoses through which fuel
    will be pumped to the launching rocket. The maximum altitude could be up to
    20 miles. I made a few (very general) calcs and it doesn't add up in terms of the fuel you need to pump - once the rocket is at a few miles per second.

    Live long and prosper.
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