Author Topic: Space Track Launch System  (Read 37640 times)

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #60 on: 12/31/2011 05:51 PM »
Jerry: I'd "suggest" at this point you do NOT let yourself get "side-tracked" with answering issues of "justification" (ie: Space Colonization, Resource Mining, etc) because there currently IS no "justification" that can stand up in logical discussion. And it doesn't directly apply to the feasability of the concept in any case. I'd also defer any questions on financial feasabilty to a later date for the reason cited above; You're not far enough along yet to do more than SWAG those details at this point.

   Thanks Randy and I agree. I've let myself get distracted. So, let me reiterate the main purpose behind this thread. It is to present an idea, a concept, for routine and economical access to space. Is it technically feasible? Can you as a reviewer on this thread find an engineering and/or physics flaw in the concept? If so and I can't resolve the issue, then I can abandon the effort. But so far I've seen no compelling argument against the technical feasibility of the concept.

   Please keep in mind that this is a second generation system. Some of the material technology is in the very early research phase of development (e.g. carbon nanotube ribbons, solid state lasers, GaAs photovoltaic cells, etc.). I wanted to conceptualize and debate the second generation system first. This will help me to define the technology development for the first generation system. I am presently working on a conceptual design of the first generation system. Since it will be based on currently available technology, I will include a rudimentary cost vs benefit analysis.

Quote from: RanulfC
Jerry: Dont' get pulled into a "location" argument either at this point, simply state that it COULD be located just about anywhere and leave it at that. As an FYI though, an island near the equator would have many advantages as you could tap Ocean Thermal Energy (OTEC) for power production AND cooling water for the laser arrays. The location also offers fewer weather related issues.

As far as location goes, I prefer a location in the continental US. There are several sparsely populated areas in the US that would be ideal. However, they are sparsely populated because of lack of water and other utilities. I'm looking into generating power from the jet stream (power densities of 12 to 14 kw/m2 between 8 and 10 km) and yes, moisture farming (check out www.aquasciences.com before you laugh). Both could be a source of revenue.

Jerry
P.S. Thanks for the lasermotive link. It may be just what I'm looking for.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #61 on: 12/31/2011 06:09 PM »

1.  How much hydrogen does it take to fill a series of 150-km towers, and how does this requirement compare to the worldwide production of hydrogen?  How much does hydrogen cost?  Just estimating the costs of some of the basic materials will give you some idea of how (wildly) expensive this project might be.

  It will be difficult to estimate the amount of hydrogen required to fill the six tower structures. The number of moles of hydrogen depend on the pressure, volume and temperature all of which vary greatly between 20 km and 150 km.

  As far as the cost of hydrogen, I will most likely produce it on site at my expense. The hydrogen will continuosly diffuse through the material and must be replaced on a periodic basis. I believe it would be more cost effective to produce it on site.

  If the benefits don't out weigh the cost, it won't be done.

Offline MikeAtkinson

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Re: Space Track Launch System
« Reply #62 on: 12/31/2011 06:12 PM »
Maybe I'm being thick, but I don't understand. The ribons hang down when not rotating, don't they? As they are spun up how do they not contact with the guy wires?

Edit:
I'm being thick, presumably the ribons are spooled out as they are rotated.
« Last Edit: 12/31/2011 06:30 PM by MikeAtkinson »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #63 on: 12/31/2011 08:45 PM »
Maybe I'm being thick, but I don't understand. The ribons hang down when not rotating, don't they? As they are spun up how do they not contact with the guy wires?

Edit:
I'm being thick, presumably the ribons are spooled out as they are rotated.

Yes, the ribbons are spooled out as the tower truss rotates. It is a layered approach. The first ribbon is spooled out as the tower truss angular velocity decreases then the remaining ribbons are layered on top of the first. They can be removed from the tower by the reverse process.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #64 on: 12/31/2011 08:51 PM »
The concept is a literal mathematical extrapolation of the forces involved in a rotating tower/slinging device to the scale of the system sketched by Mr. Fisher.  An extrapolation is not a demonstration.

Great! This is the kind of criticism I'm looking for. I believe my equations are based on sound physics and engineering principles. Many equations are taken right out of college text. If there is a literal mathematical extrapolation of any kind, please point it out and lets debate it. By the way, what do you mean by literal mathematical extrapolation?

Jerry

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #65 on: 01/01/2012 01:16 PM »
Since I understand that the equations for a rotating tower ten inches tall are the same as for one 150km tall, I call it a literal mathematical extrapolation.
Sometimes I just flat out don't get it.

Offline MikeAtkinson

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Re: Space Track Launch System
« Reply #66 on: 01/01/2012 02:55 PM »
I don't think you have accounted for the guy wires correctly. To stabalise the structure they must exert a considerable downward force (due to their weight and tension). This force has to be added to that which is countered by the hydrogen/helium in the towers.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #67 on: 01/01/2012 07:32 PM »
Since I understand that the equations for a rotating tower ten inches tall are the same as for one 150km tall, I call it a literal mathematical extrapolation.

   Then you are correct. It is an extrapolation. In the referenced paper, the authors built a 7 m tower in a stairwell out of fibre reinforced polyethylene material, validating their equations on a small scale. The authors then extrapolated their results to 20 km tower using kevlar. Their calculations are based on sound physics and engineering principles. They conclude that it is possible to build a 20 km tower out of Kevlar.

   I've extrapolated their extrapolation to 150 km using carbon nanotube fibers at a much higher internal pressure. If this is what you call a literal mathmatical extrapolation, then I'm guilty. But, it does not invalidate the concept. To my knowledge, no one has built an inflatable tower to 100 m much less 20 km and 150 km. Until we do, it remains a mathmatical extrapolation.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #68 on: 01/01/2012 08:02 PM »
I don't think you have accounted for the guy wires correctly. To stabalise the structure they must exert a considerable downward force (due to their weight and tension). This force has to be added to that which is countered by the hydrogen/helium in the towers.

  Mass loading from the guy wires has been taken into account. But, tension loading due to the precession of the tower has not. I assumed uniform load distribution to determine the mass of the tower interface ring. This is clearly not the case. The precession of the tower introduces a dynamic load of approximately 107 N doubling the load on the northern most tower. A method will have to be devised to distribute that load more uniformly or increase the thickness of the wall which has mass implications down the tower. Thanks, you just brightened my day. :(

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #69 on: 01/02/2012 01:09 PM »
I've extrapolated their extrapolation to 150 km using carbon nanotube fibers at a much higher internal pressure. If this is what you call a literal mathmatical extrapolation, then I'm guilty. But, it does not invalidate the concept.

Although I don't much care for the concept, largely for the same reasons that I don't care for the space elevator concept, it not the concept which is at fault.  The specific implementation that you depict will not work.  To the extent that it appears to depend on this literal extrapolation, it is doomed to failure.

Another way to put this is that your methodology is completely invalid, since it does not acount for the complex physical interactions of the launch system with the Earth, its atmosphere, and the characteristics of LEO, and the actual launch of an 80ton vehicle, for one thing.  Instead, you insist that a particular equation here and there is correct, as if a series of correct equations linked together without a view towards the whole structure somehow results in that whole structure being a correct implementation.  I have pointed out just a few of the many interfaces where problems will most assuredly occur, and where a few literal equations can do little to solve the problems of the interfaces. 

You do not demonstrate an actual solution for these few things which I have mentioned.  You should make an animation, to scale, of this spaghetti structure loading itself up, and spinning off a launch vehicle.  You have overlooked the big picture of the project, lost in the calculation of the diameter of the frangible bolts.
Sometimes I just flat out don't get it.

Offline Andrew_W

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Re: Space Track Launch System
« Reply #70 on: 01/02/2012 05:05 PM »
Just throwing this out there: Could it be stabilized with gyroscopes and gas jets rather than guy wires?

Either way, I'm afraid I agree with John; it sounds like too much of a flying spaghetti monster.
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years.
Wilbur Wright

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #71 on: 01/26/2012 07:37 PM »
Sorry for the absence. I've been plowing through a dissertation by Raj Kumar Seth titled "On the Design and Feasibility of a Pneumatically Supported Actively Guided Space Tower". If your interested in multi-beam inflatable towers, you might want to get a copy at:

http://gradworks.umi.com/NR/68/NR68582.html

The pdf cost $37 but I think it is worth it. You can go the cheap route and get his paper on multi-beam inflatable towers at:

http://pi.library.yorku.ca/dspace/bitstream/handle/10315/4511/JBIS_vol62_pp342-353.pdf

The free version only covers section 7 of the dissertation but the interesting stuff is there anyway.

   After reviewing Dr Seth's dissertation, I've got some good news and bad news. First, the good news. The STLS is the largest gyroscope in the known universe. The angular momentum of the tower will resist any lateral tip displacement of the tower. However, as with all gyroscopes, an unbalanced force will set up an oscillation which could grow out of control if not checked. To keep tip displacement to a minimum, the pressure in the inflated beams can be varied as needed.

  Now, the bad news. Torque appears to be the main design driver, at least at the top of the tower. Torque occurs during start up of the tower and during restoration of the kinetic energy of rotation after launch. Torque forces exceed the critical bending moment of the first 10 km layer of cylinders at the top of the tower as designed.  The torque has to be removed before increasing the length of the cylinders or cylinder height will be limited to 10-15 m which is unacceptable in a 150 km tower.

   To remove the torque, a 100m section of inflated beams called the torque buffer can be inserted between the interface ring at the bottom of the research station and the support towers. The torque buffer is made up of 10 layers. Each layer is connected to six guy wires and is made up of 60, 10m long, 1m diameter inflated beams. The guy wires bleed off the torque produced by the electric motors. Once the torque is removed, the design driver becomes the critical buckling load.

   The critical buckling load is some more bad news. I've had to angle the beams out a half degree (.009 rad) to add more cylinders as the load increases and make it more stable. The first layer has 16 beams at .8 km long, the second layer has 27 beams at 1.5 km long, and so forth. The final layer has 2028 beams at 10 km long. The base diameter is about 3 km. The whole base station can fit under the tower. Still technically feasible but much more expensive and harder to maintain (not impossible, just harder).

   I've updated my web site at fisherspacesystems.com with the latest tower concept paper. The major update is in section 2h, 3, and 4.

Online QuantumG

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Re: Space Track Launch System
« Reply #72 on: 02/01/2012 10:31 AM »
Some good work here.
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline RanulfC

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From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #74 on: 02/02/2012 12:31 PM »
Note the spread of the guy wires on the report that Randy posted.
Sometimes I just flat out don't get it.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #75 on: 02/03/2012 01:20 PM »
Some good work here.

  Thanks QuantumG! Technically feasible or not it is nice to hear some good comments about my work as well as all the others that I reference in my work.

  Thanks for the link Randy. I've been looking for a free copy of that paper. I will add the link to my web site.

  It is true. I haven't launched an 80 ton spacecraft from a ribbon. In fact, no one has. That is why I will have a research and development phase. I will not build the system to 150 km and try to launch an 80 ton spacecraft without going through a product development phase.

  As presently conceived, there will be four phases of development. First, a 25 km tower for test and evaluation of the concept. Then a 50 km tower for suborbital flights and further testing. Followed by a first generation tower at 100 km for orbital flights of a single manned spacecraft and cargo delivery of up to 150 kg per launch vehicle. Finally, the second generation system with 5-6 people or 1,500 kg of cargo per launch vehicle. At any point along the way, the whole concept may prove to be impossible.

  In the meantime, this is how I envision a cargo launch to go. The cargo for an unfueled 15 ton spacecraft attached to the overcarriage is prepped and loaded onto the spacecraft in the payload processing facility at Fisher Space Systems, LLC. The spacecraft is towed out of the facility via a composite track system. The spacecraft reaches the main track line, rotates on a turntable, and continues on to the main cargo elevator.

  At the main elevator, the spacecraft is fueled and prepped for launch. The mass of the spacecraft is now 80 ton. The spacecraft is lifted onto the rotating truss at the top of the tower. Travel time is about 5 hours at an average speed 30 km/hr. At the appropriate time, the brake is released and the overcarriage and spacecraft accelerate down the ribbon.

  At the launch point, the ignition sequence begins and the "frangible nuts" fire. The spacecraft is ejected from the overcarriage. The overcarriage returns to the launch site and prepped for the next launch. The 80 ton cargo vehicle rendezvous with the Fisher Space Systems space depot lets say at a 35 degree inclination in a few hours. If you don't think a rendezvous in a few hours is possible, check out the Gemini and Agenda rendezvous.

  After the cargo is off loaded, the OMS fires and the spacecraft reenters the atmosphere. Reentry is Apollo style, i.e. butt first. The heat shield is ablative and the 15 ton spacecraft glides back to the launch site using a para foil wing system. The spacecraft is prepped in a few days for the next cargo launch.

  Now what is so difficult about that. With the exception of lifting onto a rotating truss and launching from the ribbon (which is the uniqueness of the concept I might add), everything else is routine. If the engines don't ignite, blow out the propellants and return home and try again the next day.

  The space depot could be at any inclination. If customers want cheap supplies in LEO, they'll have to come to the space depot and get them. Or, there could be a delivery service at a nominal cost.

  I'm not waiting for the market. I'm creating the market. That is how you generate wealth. That is how Steve Jobs, Bill Gates, and Paul Allen generated wealth. They created the market. Not only did they generate personal wealth, they created a lot of millionaires along the way and provided hundreds of thousands of new jobs.

Onward and Upward,
Jerry

« Last Edit: 02/03/2012 02:26 PM by Jerry Fisher »

Online QuantumG

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Re: Space Track Launch System
« Reply #76 on: 02/03/2012 03:52 PM »
  As presently conceived, there will be four phases of development. First, a 25 km tower for test and evaluation of the concept.

Why not a 25 m tower? Seems you could make a nice model of the whole system and work out a lot of issues before moving on to something huge.
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline Jim

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Re: Space Track Launch System
« Reply #77 on: 02/03/2012 03:56 PM »
, check out the Gemini and Agenda rendezvous.


1 second launch window with a vehicle that had a high T/W for maneuvering thrusters and excess delta V.  Also, the launch window does not repeat for the next day.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #78 on: 02/10/2012 01:52 PM »

Why not a 25 m tower? Seems you could make a nice model of the whole system and work out a lot of issues before moving on to something huge.


Those are just the major milestones. Over the next 2-3 years there will be a lot of small scale testing, a lot of Y-Tube video, and a lot more 3D models and animation. I need to validate my mathematical models with some small scale testing. However, if I go any higher than 10 m, I need to get special permits from the county.

Jerry

Offline dcporter

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Re: Space Track Launch System
« Reply #79 on: 02/11/2012 01:41 PM »
Well I think you're off your rocker, but I hope the permitting goes smoothly and I wish you luck in proving me wrong. Keep us posted!

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