Author Topic: Space Track Launch System  (Read 35844 times)

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #40 on: 12/23/2011 04:07 PM »
   First, let me thank you for reading and commenting on my concept.

   Second, let me suggest a different approach. The fire hose approach will not work. The STLS, in its pre-preconcept design phase, is like a house of cards. All you need to do is find that one physics flaw and the whole house will come down (metaphorically speaking of course). I know. I've knocked the house down many times over the last eight years. But, manged to find a solution and was able to rebuild.

   Third, I'm to close to my house of cards. I've glued the edges. I need someone else to find that physics flaw. You've given it an honest try but have failed in convincing me that the concept is infeasible. Don't give up. I haven't had this much fun in a technical debate since I retired from the Air Force. So, lets go through your comments one at a time.

Such a tower has never been built in the history of mankind, and is not likely to be built in the near future, without compelling evidence for its necessity.  The above mentioned website does not present this compelling evidence for the necessity of such an engineering effort.

  True. It is not likely to be built in the near future. Maybe, I should start with a small prototype, say 10 km with a 10 km ribbon and build from there. What do you think?

  I'm not building this for some noble cause. I expect to get rich. After all, it is still a free market society (I think). I have a lot of things I want to do when I get into space and I need the money. But, I have to get there first. NASA sure isn't going to give me a ride. They will be to busy trying to survive themselves. The federal government sure isn't going to give me the $10s of billions of dollars. Our country is broke and will be for a long time. So, I have to generate the revenue myself . The rest of you can help me build it (see creative commons license) and share in the wealth ("A rising tide lifts all ships." John Salazar, US House of Representatives) or sit on the sidelines and watch the rest of use get rich.

  I think it is necessary and the compelling evidence has been presented in other documents (Bradley C. Edwards and Eric A. Westling, "The Space Elevator", "Liftport, Opening Space to Everyone", edited by Bill Fawcett, Michael Laine, & Tom Nugent Jr., to name a few). Why repeat what others have so eloquently expressed. I've got my hands full just trying to get there.

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On page 002, the website considers a payload of 530 kg, but here on page 003, the payload is now considered to be as high as 80 tons, not including the mass of the overcarriage nor the counterweight.  There has not been presented a believable method by which the initial capacity of the facility can be expanded to its presumably final capacity.  With regard to the system's hypothetical feasibility, it is immediately apparent that the cost of developing such a growth path would be a major impediment to any such feasibility.

   Page 002 states a first generation system should be able to place a payload of 530 kg into LEO. The second stage mass for the first generation system should be around 20-25 ton. Page 003 states the second stage launch vehicle will have a mass no larger than 80 ton. This is the mass of the second stage launch vehicle for the second generation system. The payload mass is approximately 1,500 kg. Sorry for the confusion.

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As illustrated, it most certainly is not a re-entry vehicle.

   That is just the skeleton. The second paragraph clearly states,

 "It has an aerodynamic shell to protect the structure during reentry, body flaps for attitude control in the atmosphere, reaction control system for attitude control in space, prime power and avionics, landing gear, and a parafoil for landing."

   If I put an aerodynamic shell in the illustration covering the skeleton, it would just be another pretty reentry vehicle. You wouldn't see the air bearings, the tapered rollers, or the composite nitrogen supply tanks. That is the exciting stuff. Because it is a reentry vehicle, it will be the first project for Fisher Space Systems, LLC. I will garner the experience of building a reentry vehicle before I tackle the next project which is building a second stage launch vehicle.

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It is inconceivable to think that 60kW of power can effectively rotate a structure of 400km in diameter.  It is not discussed in any of the articles so far, how the envisioned structural mass and launch mass gets from sea level to 150 km altitude.

   You are correct. Sixty kilowatts of power can not rotate this structure. Four 5 MW superconducting electric motors rotate this structure. The superconducting motors already exist as prototypes to 50 MW superconducting electric motors built for nuclear powered aircraft carriers (see the reference material accompanying the concept paper).

  The counterweight is a counterweight. It doesn't rotate anything. However, as the ribbon is being deployed from the rotating tower, the motor generators on the counterweight are used in the generator mode for braking and control much the same way as the motor generators in an electric car charge up batteries during braking. The motor generators generate 60 kW of power which must be dissipated through the nichrome wires. Incidentally, it is nichrome wires that heat your toast in the toaster (that is where I got the idea on how to dissipate the energy generated by the motors). Some of that energy will be stored in lithium batteries on board the counterweight. The batteries will provide the power to adjust the counterweights along the ribbon during launch. Movement of the counterweights up and down the ribbon will help absorb some of the shock from launch and dampen the oscillations of the ribbon.

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Power is delivered to the counterweights by ground based high powered solid state lasers. Solar panels made of Aluminum Gallium Arsenide photovoltaic cells receive the energy from the lasers.

This is not believable.  Earlier in the thread, the author has rejected out of hand any discussion of costs as being pertinent to the idea of feasibility.  Here is a new power transmission scheme which has not been considered sufficiently.

  On the contrary, Lawrence Livermore National Laboratory has done lethality testing and modeling using a high-power solid-state laser (Abbott, R.P. et el, 2006, “High-Power Solid-State Laser: Lethality Testing and Modeling”, 25th Annual Army Science Conference, UCRL-CONF-224732, September 26, 2006). The laser is meant for tactical battlefield applications and can be scaled to approximately 150 kW. It is compatible with the AlGaAs photovoltaic cells and has a transmission efficiency of 90% through the lower atmosphere.

   The AlGaAs photovoltaic cells respond to a wavelength of 0.84 microns and are based on the research done by F.X. D’Amato (Abbott, R.P. et el, 2006, “High-Power Solid-State Laser: Lethality Testing and Modeling”, 25th Annual Army Science Conference, UCRL-CONF-224732, September 26, 2006). The efficiency is 59% at a maximum intensity of 54 kW/m2. To deliver 80 kW of power to the motors at 59% efficiency would require an intensity of 136 kW/m2, which is slightly below the maximum intensity delivered to the test cells described in the paper. Accounting for any additional losses, a 4.0 m2 area should be enough to deliver the required energy to the 4 motors.

   Will it cost a lot? You betcha. But the cost of not rolling in the ribbons for maintenance, repair, and/or replacement will be greater (i.e. catastrophic to say the least). Have I rejected cost? No. But, I refuse to do a cost/benefit analysis until I have a feasible concept. Costing at this time is way premature and meaningless.

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    The tower is from 100-150 km high and supports an estimated 3,100 tons of passenger elevators, cargo elevators, research station, rotating truss and ribbons.

This launch scheme is completely infeasible.

   On the contrary, nothing you've said above backs up this claim. The only thing your comments show is that you've tried to disprove my concept by skimming the introductory remarks covering each subsystem and you didn't even get to the tower. Without reading the detailed technical information in the concept papers, you can not give a true technical evaluation of this concept.

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The following are a few excerpts from the backup PDF's used to support the contentions.

    Joseph A. Carroll (Carroll, J.A.,1986). Carroll suggested that a rotating sling on the surface of an airless body such as the moon might accelerate 10-20 kg payloads to orbital velocity.

   This is an application in a low gravity vacuum, proposing to send very small payloads into orbit.  Part of this idea was intended as an alternative to a linear mass driver.  The concept of a mass driver is for "dumb" masses to be fired in the general direction of an orbital catching device, with the expectation that the masses will then be processed by an unspecified mechanism.  Perhaps the masses are propellant, perhaps they are ore for refining.  Here, there is a thread called "Sling me to (or from) the Moon" which addresses some of these concepts.

   Merely to show similar applications. The masses are smaller but the physics is the same. About 10-20 kg is all you can launch from the end of a ribbon. Not big enough for my purpose. Besides, you have to get to the moon first, build a tower, deploy a ribbon, get some moon shovels, load the dirt in a bucket, sling it into space, and hit the target. I have my own ideas on mining the moon which I intend to do once I get rich. Maybe, I'll start another thread.

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As illustrated the overcarriage is not a re-entry vehicle, and cannot return to the launch site, because it is too delicate to survive the forces of re-entry.  In addition,  unmanned flyback  for a 20 ton vehicle from the altitude envisioned, 150 or so km, has not been demonstrated at all, which would necessitate the development costs of proving this concept.  It is an unfeasible concept in its entirety.

   Delicate? I'm insulted. The structure is made out of M5 (There is a chemical name but I can't pronounce it. Maybe, some of you chemical engineers can. I'll just use its trade name). This material is the Army's replacement for battlefield armor. It has a demonstrated tensile strength of 5.5 GPa and a compressive strength of 2 GPa. It is the greatest thing since sliced bread. If they reach their goal of 10 GPa during production, I'll use it as my ribbon material instead of Spectra 2000. Both are resistant to UV radiation. A bonus feature in the upper atmosphere. Dupont and Magellan are building a pilot production plant in Richmond, VA as we speak. Although, it was suppose to be finished by now. Must be some production problems. I'm sure they will work it out.

   Besides, this is just the skeleton. I'm sure I'll work it out during the prototype phase at 10 km, preliminary operations at 25, 50, 100, and full operations at 150 km. Don't worry, the development cost will be mine.

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This is an example of taking the facts of an ultimate strength and modulus of elasticity of a single material and simple geometry, and incorrectly applying these values to the vastly more complex materials and geometry of the 80 ton craft being envisioned.  This paper goes on to discuss the four frangible nuts necessary for holding the LV to the launch structure until the proper speed has been obtained.  This is an example of improper attention to detail.  The entire scheme is unrealistic; that the bolt strength is calculated to the extent that it is, does not bolster the feasibility of the entire scheme.

   Once again you are skimming the concept paper, not getting the full picture, and drawing the wrong conclusion. Allow me to explain. The ejector segment is 1 m2. I'm no engineer and don't claim to be one but, the strength of the ejector segment is 3 orders of magnitude greater than the load (that's 1,000 times the load). So, where's the problem? When the ultimate tensile strength is 3 orders of magnitude greater than the load, a safety factor of 6 is meaningless.

  Besides, I was just getting a mass estimate for the ejector. The final mass estimate for the entire overcarriage is approximately 8 ton. I will have to add mass to bring it up to 20 tons (probably with water tanks which can be emptied on reentry to lighten the load for landing or maybe I'll let some space divers go for a ride, at cost of course. They can jump out after reentry). A 20 ton overcarriage for an 80 ton launch vehicle is required for the ribbon dynamics. If I need a more robust ejector, I'll make a more robust ejector and subtract the mass from the mass budget. If I need stronger frangible nuts, I'll make stronger frangible nuts and subtract the mass from the mass budget. Nothing in your argument shows that it is unrealistic.

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The air bearings are intended to provide a lifting force to support the launch loads, presumably.  However, at the intended launch altitude, air resistance is thought to be virtually negligible.  It is not clear to me how these devices are thought to work.

   Oh, come on. This is one of my greatest innovations (a house of cards thingy). The air resistance or lack of it in this case has nothing to do with the air bearings. In fact, the vacuum helps the flow of air. Actually nitrogen is the working fluid. Air bearings is just a generic term. The support strut is stationary. The wheel rotates at approximately 300,000 rpm. The friction generated by direct contact would destroy the entire structure. Magnetic or air bearings are required. I chose air bearings.

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As illustrated, there are no "conventional" aspects to the fuselage design.

   Stop looking at the pretty picture and read the concept paper.

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An assumption without justification.

   Well you got me there? I really don't need a hydraulic system since the surface control and actuators use pneumatic actuators? I'll have to scratch that from the design.

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This is an inadequate foundation analysis.

   True. It is only the beginning. Most text books on structures approach an initial design by designing for a static load first, throw in a large safety factor, and then analyze the dynamic load. The dynamic load analysis has not been done. But, lets look at the static load of 921 psi. That is miniscule when you consider that the high pressure concrete used in the footers for the Hoover Dam bridge project can withstand static loads of 10,000 psi. Plenty of safety factor when I start the dynamic loading analysis. 
« Last Edit: 01/10/2012 12:50 AM by Jerry Fisher »

Offline Chris Bergin

Re: Space Track Launch System
« Reply #41 on: 12/23/2011 07:33 PM »
Right, thread cleaned, and it's future civility will be upheld without exception.

If civility is breached, do not post a reaction!! Report to moderator.

Jerry, learn how to deal with critics, because reading through this thread, you're opening yourself up for being tagged as confrontational.

Thread will be pulled if it doesn't improve.

Offline Andrew_W

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Re: Space Track Launch System
« Reply #42 on: 12/23/2011 07:36 PM »
Jerry, I'm afraid I'm not qualified to offer an opinion on the engineering of your concept, all I can say is that you do need to recognize that even if there are no, zero, zip, technical obstacles to the construction of a STLS, it still has to make sense in financial terms, there have been a lot of alternatives to current methods used to get to orbit proposed, many of which could work in technical terms, all have so far failed to get finance.

Why, from a financial perspective, is your system a better bet than laser/microwave launch or super guns or space fountains/launch loops?
« Last Edit: 12/23/2011 07:55 PM by Andrew_W »
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Offline Jim

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Re: Space Track Launch System
« Reply #43 on: 12/23/2011 08:20 PM »

Why, from a financial perspective, is your system a better bet than laser/microwave launch or super guns or space fountains/launch loops?

Why compare it to three concepts that are also not proven?

It is like comparing unicorns to fairies, dragons and leprechauns.

Offline mmeijeri

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Re: Space Track Launch System
« Reply #44 on: 12/23/2011 08:21 PM »
It is like comparing unicorns to fairies, dragons and leprechauns.

Easy now, Dragons do exist!  :P
We will be vic-toooooo-ri-ous!!!

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #45 on: 12/24/2011 12:51 AM »
Martijn: 2 points.
Sometimes I just flat out don't get it.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #46 on: 12/24/2011 01:20 AM »
Jerry, I'm afraid I'm not qualified to offer an opinion on the engineering of your concept, all I can say is that you do need to recognize that even if there are no, zero, zip, technical obstacles to the construction of a STLS, it still has to make sense in financial terms, there have been a lot of alternatives to current methods used to get to orbit proposed, many of which could work in technical terms, all have so far failed to get finance.

Why, from a financial perspective, is your system a better bet than laser/microwave launch or super guns or space fountains/launch loops?

   I can answer your question from a technical perspective but not from a financial perspective. It is way to early to do a cost vs benefit analysis. But, I do agree with you. The STLS will make sense from a financial perspective or it won't be built. It has to make sense or I won't get rich. That may sound greedy but, that is the bottom line.

  The second generation system is where I want to go with my concept. The first generation system is how I will get there. I'm still defining where I want to go. There has been some good input here but, I would like to continue the technical debate.

Offline Andrew_W

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Re: Space Track Launch System
« Reply #47 on: 12/24/2011 03:55 AM »

Why, from a financial perspective, is your system a better bet than laser/microwave launch or super guns or space fountains/launch loops?

Why compare it to three concepts that are also not proven?

It is like comparing unicorns to fairies, dragons and leprechauns.

I'm pretty sure that unicorns, fairies, dragons and leprechauns are somewhere out past oogie boogie science and not appropriate to this forum.

If you're going to invest in, lets say, the first manned flight to the Moon, you're going to be comparing many unproven concepts to select the best (safest, most cost competitive) options, if you're going to invest in the worlds first reusable launch vehicle, again you need to select the best of the (unproven) options, if you're going to do anything new, you'll end up disposing of some of the options before you start cutting metal.

you can argue that any new concept should first be compared to existing methods, and if it's not economically competitive with those existing methods argue that it's not viable, but that reasoning ignores the fact that the economic viability of different options changes with time, building 747's would not have been viable in 1950, and the industry consensus was that it wasn't viable in the '60's either, but Boeing built it any way. Your logic says they should have compared it's viability to what already existed (the 707, the DC8), rather than to what was to come.
« Last Edit: 12/24/2011 03:57 AM by Andrew_W »
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years.
Wilbur Wright

Offline johncarpinelli

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Re: Space Track Launch System
« Reply #48 on: 12/24/2011 06:12 AM »
I agree that some economic analysis is needed upfront.  The economics are one of the biggest selling points of this system.  You need to look at costs and revenue.  Revenue from aviation may be considerably higher than space launch. 

This system could be built for less than one tenth the cost of the ISS in my opinion.  Remember we are talking about inflatable towers, not concrete skyscrapers.  A 10km tower would be a very cheap source of air transport. Mining companies could fund one to ship ore from a remote mine for example.  After riding an electric lift, aircraft would have a gliding range of 200km or more without burning any fuel. 

The 10km tower has been analyzed in peer reviewed studies and found to be feasible. 

Offline Jim

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Re: Space Track Launch System
« Reply #49 on: 12/24/2011 11:50 AM »
building 747's would not have been viable in 1950,

Not possible

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #50 on: 12/24/2011 12:38 PM »
I agree that some economic analysis is needed upfront.  The economics are one of the biggest selling points of this system.  You need to look at costs and revenue.  Revenue from aviation may be considerably higher than space launch. 

The 10km tower has been analyzed in peer reviewed studies and found to be feasible. 

   "Resistance is futile" - John Lauc Pachard, Borg Mother Ship.

   :-[ I'll need some guidance. I'm much better with the physics than I am with the finances.

  The revenue from aviation is something I haven't considered. The downrange distance for the overcarriage is approximately 2,000 km and that is just a ballistic trajectory. If we replace the second stage launch vehicle with a glider, we could launch cargo over the north pole. In fact, we could even launch people. Maybe we could reconfigure the overcarriage into a glider and launch cargo in the overcarriage and people in the glider. After all, the tower has a 360 degree launching window.

  The 10 km tower studies, I have them somewhere. I moved last year and most of my raw material is still packed away. Thanks for reminding me. I'll dig them out and start there.

   :) This could be fun.

   After Christmas, of course. Merry Christmas!!!
« Last Edit: 12/24/2011 12:43 PM by Jerry Fisher »

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #51 on: 12/24/2011 02:24 PM »
I'm pretty sure that unicorns, fairies, dragons and leprechauns are somewhere out past oogie boogie science and not appropriate to this forum.

And a point to Andrew for judicious use of the strikeout feature.  I continue to insist that ponies are appropriate in some of these discussions.
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #52 on: 12/24/2011 02:25 PM »
Quote from: JF
Such a tower has never been built...

It is not likely to be built in the near future...

Put your considerable talents to some other use. 

I include a scan of your tower concept drawn to scale, with the tower located somewhere in the center of Florida.  You have not specified a location for this system, so I did.  It would be infeasible to clear the real estate in Florida to implement the tower/ribbon system.  Perhaps it would be more feasible to consider an island somewhere, but even so, there would have to be negotiated significant changes in global airspace, to allow clearance for such a continually operating system.  Without doing any further calculations, the scale of the enterprise is too large to be realistic.

Quote from: JF
As illustrated, it most certainly is not a re-entry vehicle.

It has an aerodynamic shell to protect the structure during reentry, body flaps for attitude control in the atmosphere, reaction control system for attitude control in space, prime power and avionics, landing gear, and a parafoil for landing.

You are free to maintain that this is a feasible design, based only upon this description.

Quote from: JF
It is inconceivable to think that 60kW of power can effectively rotate a structure of 400km in diameter.

Four 5 MW superconducting electric motors rotate this structure. The superconducting motors already exist as prototypes to 50 MW superconducting electric motors built for nuclear powered aircraft carriers (see the reference material accompanying the concept paper).

There is no need to dig further into the reference material.  That a prototype of a superconducting motor should exist is insufficient proof that the superconducting motor required for this installation can be fabricated.  You are free to insist otherwise.

Quote from: JF
Here is a new power transmission scheme which has not been considered sufficiently.

Lawrence Livermore National Laboratory has done lethality testing and modeling using a high-power solid-state laser ...

The power needs of the launcher are for useful power, not destructive power.  An intermittently fired tactical weapon is not suited for the constant use needed for the rotating device. 

Quote from: JF
This launch scheme is completely infeasible.

On the contrary, nothing you've said above backs up this claim. The only thing your comments show is that you've tried to disprove my concept by skimming the introductory remarks covering each subsystem and you didn't even get to the tower. Without reading the detailed technical information in the concept papers, you can not give a true technical evaluation of this concept.

I most certainly did get to the tower.  Referring to my sketch below, it is clear that the slenderness ratio of the tower is too high to seriously merit further consideration.  For purposes of casual analysis, a tower of 3100 mt divided by 150 km, is about 20 kg per meter.  There is no way that such a lightweight tower with the functionality required included in the mass estimate can be built.  However, it is possible to calculate in great detail, various statistics about such a tower.  The calculation does not demonstrate feasibility.

This was fun. Lets do it again sometime but pick a subsystem and lets debate it.

The subsystems cannot be integrated into a functioning launch system.  It is simply not a debatable issue, but you are certainly free to reject that analysis.

I agree that some economic analysis is needed upfront.  The economics are one of the biggest selling points of this system.  You need to look at costs and revenue.

The economic analysis for this system is virtually the same analysis as would be gained should one divide by zero.  It is undefined, nor can it be defined as described on the author's website.  The online description is incomplete.

Thread will be pulled if it doesn't improve.

It is unlikely that there should be such a hoped for improvement.
Sometimes I just flat out don't get it.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #53 on: 12/24/2011 04:53 PM »
Put your considerable talents to some other use. 

   I'm retired. This gives me the chance to dream and to pursue a dream. Thanks for the compliment.

Quote from: JohnFornaro
I include a scan of your tower concept drawn to scale, with the tower located somewhere in the center of Florida.  You have not specified a location for this system, so I did.  It would be infeasible to clear the real estate in Florida to implement the tower/ribbon system.  Perhaps it would be more feasible to consider an island somewhere, but even so, there would have to be negotiated significant changes in global airspace, to allow clearance for such a continually operating system.  Without doing any further calculations, the scale of the enterprise is too large to be realistic.

   The scale is daunting. But not impossible. I would prefer continental US for the large volume of traffic I expect but, there is an island in the south pacific near the equator that would be perfect for the STLS, a tropical paradise. It is US territory and has been up for sale for awhile. There are a few islands nearby, so I would have to negotiate airspace issues.

Quote from: JohnFornaro
The power needs of the launcher are for useful power, not destructive power.  An intermittently fired tactical weapon is not suited for the constant use needed for the rotating device.

   I have a 30o arc to fire the solid-state laser. It is not continuous. Although, it will fire longer than it takes to bring down a ballistic missile with the Airborne Laser Lab. Some R&D in cooling the laser will be required. But not impossible.

Quote from: JohnFornaro
I most certainly did get to the tower.  Referring to my sketch below, it is clear that the slenderness ratio of the tower is too high to seriously merit further consideration.  For purposes of casual analysis, a tower of 3100 mt divided by 150 km, is about 20 kg per meter.  There is no way that such a lightweight tower with the functionality required included in the mass estimate can be built.  However, it is possible to calculate in great detail, various statistics about such a tower.  The calculation does not demonstrate feasibility.

   My apologies. You did get to the tower. The slenderness ratio is used for a tower under compression. This is a tower under tension. The hoop stress is more appropriate here.

Quote from: JohnFornaro
The online description is incomplete.

Be patient. I'm working on it.

Quote from: JohnFornaro
Thread will be pulled if it doesn't improve.

It is unlikely that there should be such a hoped for improvement.

  I believe Chris was referring to civility. It is comments like this that sent me postal in the first place. I've been censored twice and only been posting for 3 weeks. It is very humbling. I've spent most of the morning cleaning up previous post and removing inflammatory language. I'm trying to be nice but it is hard sometime.
« Last Edit: 01/10/2012 01:00 AM by Jerry Fisher »

Offline KristianAndresen

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Re: Space Track Launch System
« Reply #54 on: 12/25/2011 12:31 AM »
Quote
This is a tower under tension.

Where does the tension come from when most of the tower is outside the atmosphere?

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #55 on: 12/25/2011 01:04 AM »
Quote
This is a tower under tension.

Where does the tension come from when most of the tower is outside the atmosphere?

   The tension comes from the fill gas inside of the tower. In this case, the fill gas is hydrogen. Because most of the tower is outside of the atmosphere, there is a vacuum on the outside of the tower wall and hydrogen gas on the inside. The hydrogen gas exerts a pressure on the walls of the tower and keeps the walls rigid. The hydrogen gas also exerts a pressure on the ceiling of the tower which supports the structure. The stronger the material, the higher the gas pressure, and greater the mass which can be supported.
« Last Edit: 12/26/2011 12:17 AM by Jerry Fisher »

Offline RanulfC

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Re: Space Track Launch System
« Reply #56 on: 12/30/2011 08:43 PM »

Why, from a financial perspective, is your system a better bet than laser/microwave launch or super guns or space fountains/launch loops?

Why compare it to three concepts that are also not proven?

It is like comparing unicorns to fairies, dragons and leprechauns.
The basic "question" Andrew_W asks is very valid, and while it should be adressed it would take a lot more detailed design and costing than Jerry has currently devoted to the project. Note that he's looking for feedback vis-a-vis the overall concept feasability. So far the only one I've seen actually tackle that issue is John Forano.

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.

So far the "major" arguments seem to be "it's never been done before" and "my assumptions are different than your assumptions so using my assumptions it won't work" or arguments to those effects....

Jim:
FYI, now where in any of the information presented or being discussed is the requirement that the concept or idea being "proven" prior to being discussed. You state:
Quote
Why compare it to three concepts that are also not proven?

It is like comparing unicorns to fairies, dragons and leprechauns.
"Proven" is not even in the runing here as you then descend into listing FANTASY creatures? Come on, you are FAR better than this and far to smart to have made the simple and basic mistake you did:
ALL of the listed concepts are TECHNICALLY FEASABLE, most having been either prototyped and/or lab-tested (as far as I can find the Space Fountain/Launch Loop is the only concepts mentioned that has not) and while they are not currently considered actually VIABLE (financially or lacking technology) launch systems they technically possible given the needed incentive.

If you don't think the idea is feasable, feel free to get into details that's what Jerry is looking for, but I'm guessing you'd be hard pressed to come to any definative "argument" against the concept except one of the two I cited above...

Quote from: JohnFornaro
The power needs of the launcher are for useful power, not destructive power.  An intermittently fired tactical weapon is not suited for the constant use needed for the rotating device.
Quote from: Jerry Fisher
   I have a 30o arc to fire the solid-state laser. It is not continuous. Although, it will fire longer than it takes to bring down a ballistic missile with the Airborne Laser Lab. Some R&D in cooling the laser will be required. But not impossible.
John; Here's your "answer":
http://lasermotive.com/

-12.5 hours continous flight... With a 5-minute battery on-board :)

Put your considerable talents to some other use. 

   I'm retired. This gives me the chance to dream and to pursue a dream. Thanks for the compliment.

Quote from: JohnFornaro
I include a scan of your tower concept drawn to scale, with the tower located somewhere in the center of Florida.  You have not specified a location for this system, so I did.  It would be infeasible to clear the real estate in Florida to implement the tower/ribbon system.  Perhaps it would be more feasible to consider an island somewhere, but even so, there would have to be negotiated significant changes in global airspace, to allow clearance for such a continually operating system.  Without doing any further calculations, the scale of the enterprise is too large to be realistic.

   The scale is daunting. But not impossible. I would prefer continental US for the large volume of traffic I expect but, there is an island in the south pacific near the equator that would be perfect for the STLS, a tropical paradise. It is US territory and has been up for sale for awhile. There are a few islands nearby, so I would have to negotiate airspace issues.

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.

Randy

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 mrmandias

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Re: Space Track Launch System
« Reply #57 on: 12/30/2011 10:16 PM »
Some thoughts:

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.

2.  Given the area your ribbons will sweep out, your project would require political action at the national level.  Probably true also for the funding.  So this is not a private, get-rich system.  But speaking as a lawyer, even if you had private financing somehow, the level of regulatory, property-rights, treaty, and legal complexity you are talking about here would require that your project be a very high-level government project with specific congressional enabling legislation.

3.  Using this project for point to point transport doesn't sound practical.  You have no real mechanism for landing your second stage craft or returning them once landed.  Getting from the ground to the tower is going to take time, probably enough time that it cancels out any benefit of ballistic flight.  Further there's getting to the tower in the first place, which will be in just one location and will not and cannot be located next to major urban areas.

4.  A project like this, that is hugely radical and untried, should not rely on a number of radical and untried sub-elements.  You should rely on tried and true sub-systems, not prototype government lasers that are not remotely commercially available.  Of course, as a thought experiment there's no harm in designing a systema nd pointing out areas where requirements go beyond the current state of the art.

Offline johncarpinelli

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Re: Space Track Launch System
« Reply #58 on: 12/31/2011 07:11 AM »
There is a good chance that the design is technically feasible with sufficient development funding.  A tougher question is how to make it financially feasible to justify the investment. Smaller scale systems with terrestrial revenue are a good way to get started.

Here is an example project where the Australian government is seeking $6 billion to build a railway to move iron ore 570 km across the outback. They are looking for private investors to support the project. The requirement is to ship 100 million tons of ore to the coast for export.

http://online.wsj.com/article/SB10001424052970203479104577125680222322916.html

This requirement could possibly be met with three inflatable towers built to 10km in altitude. There would be one tower at each end of the freight route and a tower at the mid-point. The ore would be raised in unmanned freight gliders to the top of the tower and then accelerated by rotating tethers. It should be possible to achieve a glide ratio of 25 for the gliders and ship the ore 250 km from the launch tower. After landing at the base of the next tower, it would be hoisted again for the next leg.

If you could build three 10km towers for under $6 billion, there could be an economic case for such a system. You would need to budget for several hundred unmanned freight gliders also. Freight routes with impassable rivers, gorges and mountains would be even better candidates for the system.

A detailed study of the 15km tower was published in 2009. I guess that filling with hydrogen would be considerably cheaper than helium for such a large scale system.

Quote
The tower itself would be 15 kilometers (9.3 miles) tall, 230 meters (754 feet) across, and weigh approximately 800,000 tons, or about twice the weight of the world's largest supertanker when fully inflated with a variety of gasses, including helium.
http://dsc.discovery.com/news/2009/07/02/space-tower.html


The advantage of an aviation project is the immediate revenue and potential for incremental development. After mastering the 10km tower, the industry could move onto the 20km tower and gradually scale up to space. This strategy is nicely summarized on the Space Cynics blog:

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(a) find and develop a technology that both solves a problem on Earth now and can be scaled to solve a problem in space later – a product/service that customers will demand,
(b) make lots of money doing this, and finally
(c) invest a portion of profits from the established terrestrial ventures for the R&D to solve the space problem when the time is right and demand exists.

http://spacecynic.wordpress.com/money-cynics-view/

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #59 on: 12/31/2011 02:53 PM »
Randy:  Going from "TECHNICALLY FEASABLE" to "technically possible" is the mistake in this concept, and in your rendition of the concept.  The feasibility has not been demonstrated in any comprehensive sense of the word.  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.

As I said:

Quote
The calculation does not demonstrate feasibility.
Sometimes I just flat out don't get it.

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