Author Topic: Space Track Launch System  (Read 35836 times)

Offline Jerry Fisher

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Space Track Launch System
« on: 12/05/2011 04:35 PM »
      What about an all electric first stage launch system with a conventional liquid propellant second stage? I have been working on such a system called the Space Track Launch System (STLS) for about eight years. The system consist of counterweights attached to ribbons which are attached to a rotating truss mounted on a tall tower. A second stage launch vehicle travels down the ribbon accelerated by gravitational, centrifugal, and Coriolis forces. At a certain point along the ribbon, the second stage launch vehicle separates from the ribbon and proceeds to low earth orbit.

     I believe this system is unique for several reasons. First, the second stage launches from the ribbon instead of from the end of the ribbon which drastically reduces the shock produced from the launch. Second, the launch velocity is the vector addition of the radial velocity down the ribbon and the tangential velocity at the launch point. Third, the counterweights are designed to absorb some of the  shock and dampen the oscillations of the ribbon after launch. Fourth, a second launch vehicle can be launched approximately 210 seconds later, doubling the payload capacity to LEO. Finally, the kinetic energy of rotation can be restored in approximately eight hours, resulting in several launches per day.

     I am relatively new in the space access business with no prior contract experience. Unless I've missed some fundamental physics, the concept should work. However, I am a physicist and not an engineer. Therefore, I humbly submit this concept and invite the forum to critically review the STLS concept at www.fisherspacesystems.com. I look forward to your review, critique, and future collaboration.

Offline Jim

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Re: Space Track Launch System
« Reply #1 on: 12/05/2011 04:51 PM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?

Offline Andrew_W

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Re: Space Track Launch System
« Reply #2 on: 12/05/2011 05:48 PM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?

The "when it is 2 magnitudes taller than anything ever built?" isn't relevant, like all the creative alternative ideas it comes down to: Is it possible, what's the cost, and who's going to foot the bill?

This idea is the opposite of HASTOL, which would use a rocket first stage with a tether second stage, I wonder if combining the two to get a tether to tether system would be possible.
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Offline deltaV

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Re: Space Track Launch System
« Reply #3 on: 12/05/2011 05:52 PM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?
Maybe using a dynamic structure as commonly proposed for tall launch towers? See e.g. http://en.wikipedia.org/wiki/Non-rocket_spacelaunch#Dynamic_structures.

Offline Jim

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Re: Space Track Launch System
« Reply #4 on: 12/05/2011 06:22 PM »

The "when it is 2 magnitudes taller than anything ever built?" isn't relevant,

Nonsense, it is very relevant because it infers "Is it possible or feasible?"  Just because you dont get it has nothing to do with relevance.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #5 on: 12/05/2011 07:23 PM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?

That's a good question. Much, much research and development is required for this to be feasible. For a second generation tower, the tower will be approximately 150 km tall and support an estimated 3,100 metric tons. The tower will precess since it will be located anywhere from 0o to 50o north latitude. (What aerospace company wants to operate out of the north pole?) IMO, a tower under tension is the only possibility. Several authors have theorized on the possibility of tall support towers (references below).

The analysis for the support tower relies heavily on the work presented in "Feasibility of a 20 km Free-Standing Inflatable Space Tower" by R. K. Seth, B. M. Quine, and Z. H. Zhu. For the case of a second generation system, the material of choice is a carbon nanotube material with a working tensile strength of 25 GPa. The tower would be filled with hydrogen from 20 km to 150 km and helium from 0 km to 20 km. The top 10 km of tower will have to be pressurized to 4.8 x 105 N/m2. The pressure will increase as more mass is added to the tower. The initial design of the tower is in 10 km increments for the hydrogen fill and 5 km increments for the helium fill. Guy wires will be attached to retard the precession. Unfortunately, due to the elasticity of the CNT cable, the tower will sway an estimated 10 km southward with a period of 4.4 minutes. Strong stomachs are advised.

References

Fisher, J.F., 2011, Space Track Launch System - Tower, www.fisherspacesystems.com

Smitherman Jr., D.V., 2000, Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium, MASA/CP-2000-210429

Seth, R.K., Quine, B.M., and Zhu, Z.H., 2009, Feasibility of 20 Km Free-Standing Inflatable Space Tower, JBIS, Vol. 62. pp. 342-353, 2009

Bolonkin, A.A., 2003, Optimal Inflatable Space Towers with 3-100 km Height, JBIS, Vol. 56, pp. 87-97, 2003

Offline Jim

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Re: Space Track Launch System
« Reply #6 on: 12/05/2011 07:52 PM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?

That's a good question. Much, much research and development is required for this to be feasible. For a second generation tower, the tower will be approximately 150 km tall and support an estimated 3,100 metric tons. The tower will precess since it will be located anywhere from 0o to 50o north latitude. (What aerospace company wants to operate out of the north pole?) IMO, a tower under tension is the only possibility. Several authors have theorized on the possibility of tall support towers (references below).

The analysis for the support tower relies heavily on the work presented in "Feasibility of a 20 km Free-Standing Inflatable Space Tower" by R. K. Seth, B. M. Quine, and Z. H. Zhu. For the case of a second generation system, the material of choice is a carbon nanotube material with a working tensile strength of 25 GPa. The tower would be filled with hydrogen from 20 km to 150 km and helium from 0 km to 20 km. The top 10 km of tower will have to be pressurized to 4.8 x 105 N/m2. The pressure will increase as more mass is added to the tower. The initial design of the tower is in 10 km increments for the hydrogen fill and 5 km increments for the helium fill. Guy wires will be attached to retard the precession. Unfortunately, due to the elasticity of the CNT cable, the tower will sway an estimated 10 km southward with a period of 4.4 minutes. Strong stomachs are advised.

References

Fisher, J.F., 2011, Space Track Launch System - Tower, www.fisherspacesystems.com

Smitherman Jr., D.V., 2000, Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium, MASA/CP-2000-210429

Seth, R.K., Quine, B.M., and Zhu, Z.H., 2009, Feasibility of 20 Km Free-Standing Inflatable Space Tower, JBIS, Vol. 62. pp. 342-353, 2009

Bolonkin, A.A., 2003, Optimal Inflatable Space Towers with 3-100 km Height, JBIS, Vol. 56, pp. 87-97, 2003

And how are the huge costs of this infrastructure going to make spacelaunch cheaper?

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #7 on: 12/05/2011 08:18 PM »
Quote: "And how are the huge costs of this infrastructure going to make spacelaunch cheaper? "

     A detailed cost analysis has not been done. The first task is to determine if the STLS is technically feasible. As I have said in a previous post, I am a physicist not an engineer. I have had no technical review of this concept from my peers. This forum is the concepts debut.

     Having said all that, let's review the possibilities. I see this as a government owned contractor operated facility. The GOCO approach will hopefully keep the launch cost to a minimum. It will be up to the aerospace companies to fund, operate, and maintain their second stage launch vehicles.

     Why GOCO? Because of the tax revenue generated with having approximately 6 metric tons of cargo and/or people launched into space everyday. Imagine the number of aerospace companies required to meet that launch demand not to mention all of the support facilities (machine shops, fuel depots, restaurants, hotels, maids, janitors, etc.) required to keep the aerospace engineers happy. Is there a demand for 6 metric tons of cargo and/or people per day? Not today. It is a chicken and egg problem (catch 22 or whatever you want to call it). I do see launch cost several orders of magnitude less than today. But, that is just me. As I've said, a detailed cost analysis has yet to be done.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #8 on: 12/05/2011 08:34 PM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?

The "when it is 2 magnitudes taller than anything ever built?" isn't relevant, like all the creative alternative ideas it comes down to: Is it possible, what's the cost, and who's going to foot the bill?

This idea is the opposite of HASTOL, which would use a rocket first stage with a tether second stage, I wonder if combining the two to get a tether to tether system would be possible.

I have looked into catching up with MXER, docking, and transferring momentum to the launch vehicle. Launching from the tower and attaching to a tether in LEO will greatly reduce the deltaV required from the launch vehicle. It turns out that the payload capability is about doubled.

Offline RanulfC

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Re: Space Track Launch System
« Reply #9 on: 12/07/2011 02:12 PM »
This idea is the opposite of HASTOL, which would use a rocket first stage with a tether second stage, I wonder if combining the two to get a tether to tether system would be possible.
Just a slight correction Andrew but the HASTOL first stage is NOT a "rocket" it's a hypersonic-aircraft, hence the "HA" in the acronym :)

It has a small set of rockets to allow it to arc slightly  out of the atmosphere to meet the tether but the main engines are air-breathing.

Quote: "And how are the huge costs of this infrastructure going to make spacelaunch cheaper? "

     A detailed cost analysis has not been done. The first task is to determine if the STLS is technically feasible. As I have said in a previous post, I am a physicist not an engineer. I have had no technical review of this concept from my peers. This forum is the concepts debut.
Ok, the point that Jim is making doesn't really need a "detailed" cost analysis a very basic one will tell you this concept is going to cost a LOT to build due to the amount of infrastructure required.

But to your "basic" question of the concepts technical feasiblity; of course it's "feasible" and could "technically" be done. I've actually seen this same idea several times before though your suggestion of counter-weights and launching from the mid-point of the teather is an interesting variant that mitagates some of the difficulties with earlier suggestions, so further work is certainly useful.

The point Jim is trying to make would probably be better stated as asking given the mega-structure of the tower and tethers, the infrastructure, and all the associated overall costs involved how does your concept help get from where we are not to where your concept becomes "cost-effective" in terms of launch capacity and price per-pound-to-orbit?

There have been many proposals for "mega-structure" or large infrastructure scale projects that have a great capacity for putting stuff into orbit for pennies-per-pound. Launch Loops, Laser/Microwave beamed propulsion, MXER, and HASTOL just to name a few and some such as SkyRamp, of EM-Launch assist can possibly be scaled DOWN to meet current needs but they all still require an intitial investment that quite large compared to simply designing a new rocket or modifying a current one.

6 metric tonnes (@13,227lbs) per day to orbit far exceeds current demand and one thing that many advocates of space launch concepts don't seem to understand is that you MUST be able to address CURRENT needs in order to build UP future capacity. I've said it before and I will continue to point out that Space Colonization nor large scale "use" of space are NOT currently a paradigm for any government space program, and they make up a major portion of the payload market. The OTHER percentage of the market is a commercial space utilization business who have evolved to launch large payloads into specific orbits rarely and with little or no need or incentive to subsidies over-capcity or expanded capacity for space launch.

Given the above circumstances there is clearly no government forseen need or interest in a huge investment for such a system unless there can be a case made for increased national interest or dire need in the forseable future, and even less within private industry.

So having said all that, am I saying your concept has no justification and therefore you need to move on and forget about it? Oh HELL no! :)

You've done some good work so far and I say "keep it up!" Because while there is no "need" for it now that does not say that circumstances might not change in the future and even if YOUR specific concept doesn't ever get built you COULD inspire someone who's system does :)

So keep up the work and I'll try and get back after some more review with some semi-technical questions I've got on the system.

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 Jerry Fisher

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Re: Space Track Launch System
« Reply #10 on: 12/09/2011 07:45 PM »
But to your "basic" question of the concepts technical feasiblity; of course it's "feasible" and could "technically" be done. I've actually seen this same idea several times before though your suggestion of counter-weights and launching from the mid-point of the teather is an interesting variant that mitagates some of the difficulties with earlier suggestions, so further work is certainly useful.

  The idea that the second stage launch vehicle is launched from the middle of the ribbon, the idea that the overcarriage remains on the ribbon providing a retarding force, and the idea that the counterweights absorb the shock and dampen the oscillations make this concept possible.

   It is physically impossible to launch an 80 ton spacecraft with a 1.5 ton payload from earth into low earth orbit from the end of a tether more than once. First, you would only be allowed to launch cargo and not people. People would not be able to withstand the continuous 6g acceleration during the ramp up of rotational kinetic energy. Acceleration down the ribbon as in my concept is exponential going from 3g to 6g in the last 15 to 20 seconds. It is more like an impulse in acceleration as opposed to continuous.

   Second, releasing an 80 ton spacecraft from the end of the ribbon produces a compressive shock wave which travels up the ribbon at the speed of sound for the material gather energy as it goes. This energy is above or at the failure energy for the material. If it doesn't destroy the ribbon, you certainly don't want to use it again.

   Finally, when that shock wave strikes the tower, all heck is going to break loose. This is like stretching a rubber band and letting it hit your hand but, much worse. With a counterbalance on the other side, the tower will most likely collapse.

   Therefore, launching from the end of a ribbon or tether from earth to low earth orbit using spacecraft with significant payload capability is out. The tower and the ribbon will have to be replaced after every launch. Kind of like throwing the first stage away after every launch, something I'm trying to get away from.

   In my concept, launch is possible again after eight hours. But is it technically feasible? That is what I hope to answer with intense technical debates on this forum and through my web site at www.fisherspacesystems.com.
« Last Edit: 12/24/2011 02:04 PM by Jerry Fisher »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #11 on: 12/11/2011 08:59 PM »
6 metric tonnes (@13,227lbs) per day to orbit far exceeds current demand and one thing that many advocates of space launch concepts don't seem to understand is that you MUST be able to address CURRENT needs in order to build UP future capacity. I've said it before and I will continue to point out that Space Colonization nor large scale "use" of space are NOT currently a paradigm for any government space program, and they make up a major portion of the payload market. The OTHER percentage of the market is a commercial space utilization business who have evolved to launch large payloads into specific orbits rarely and with little or no need or incentive to subsidies over-capcity or expanded capacity for space launch.

   Webster's dictionary defines paradigm as a philosophical or theoretical framework of any kind. Your comment appears to be philosophical in nature. So let's talk philosophically.

   Many aerospace scientist, engineers, and administrators strongly subscribe to the current philosophy. We must be able to address current needs in order to build up future capacity. Since the government is our majority customer and they demand zero risk and have large sums of money, lets do it the tried and true way with expendable throwaway booster costing $100-$200 million a launch. I understand this paradigm.

   If the government was putting a $1 billion dollar national defense satellite into a geostationary orbit, I'd want zero risk and wouldn't mind if the launch cost $100-$200 million. I think it is great that smaller commercial companies (i.e. SpaceX and Orbital Sciences) are building future capabilities based on current needs. These companies are improving on conventional technology and driving cost down through better management of resources. But, launches still cost between $100-$200 million.

   Here is where we differ in philosophy. My definition of future needs is space based solar power satellites in geostationary orbit, mining helium 3 on the moon, prospecting and mining strategic materials on near earth asteroids and in the asteroid belt, and yes, large scale colonization to support the activities. The future needs as defined above may take a little longer to accomplish but are, in my opinion, none the less important. The planet is running out of strategic materials and energy resources and I foresee a thriving export business from space based assets to earth. And to do that, we need reusable first and second stage launch vehicles with launch cost several orders of magnitude lower than presently available. People and cargo will need to go and come from LEO on a daily basis. What I and other "space advocates" are trying to establish is a new philosophical framework for space access. The mega-structure concepts such as MXER, Space Elevator, Electromagnetic Launch, and others are laying the groundwork for a new philosophical framework for space access and I, for one, am betting on the new paradigm.
« Last Edit: 12/24/2011 02:00 PM by Jerry Fisher »

Offline Rocket Science

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Re: Space Track Launch System
« Reply #12 on: 12/11/2011 09:48 PM »
"The laws of physics are unforgiving"
~Rob, Physics instructor, aviator, vintage auto racer

Offline mboeller

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Re: Space Track Launch System
« Reply #13 on: 12/12/2011 06:01 AM »

Offline Jim

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Re: Space Track Launch System
« Reply #14 on: 12/12/2011 02:02 PM »
My definition of future needs is space based solar power satellites in geostationary orbit, mining helium 3 on the moon, prospecting and mining strategic materials on near earth asteroids and in the asteroid belt, and yes, large scale colonization to support the activities.

None of which may be technically viable or even commercially viable.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #15 on: 12/13/2011 08:11 PM »
My definition of future needs is space based solar power satellites in geostationary orbit, mining helium 3 on the moon, prospecting and mining strategic materials on near earth asteroids and in the asteroid belt, and yes, large scale colonization to support the activities.

None of which may be technically viable or even commercially viable.

On the contrary, I believe, as do many others, that they are technically and commercially viable. Lets take space based solar power satellites for example. Goggle space based solar power. Let me point out a few of the first page topics:

   - Wikipedia, ok it seems like a Wikipedia definition is always a first topic.

   - Dec 13, 2008 - "Hosted by the Space Frontier Foundation to assist the National Security Space Office study on Space-Based Solar Power development." The National Space Society published a report to the Director, National Security Space Office on the national security issues related to SBSP. The report is online at www.nss.org/settlement/ssp/library/nsso.htm.

   - Nov 14, 2011 - "A consortium of the world's leading space scientists believe that it is possible for the world to begin to meet its energy demands..." The International Academy of Astronautics has spent several years studying SBSP. Its report, completed in August, 2011, is online at iaaweb.org/iaa/Studies/sg311_finalreport_solarpower.pdf.

   - May 11, 2011 - "Space Energy seeks to improve the lives of millions of people, provide viable alternatives to polluting energy sources and help abate some of ...."  Space Energy is a space based solar power company. Their main office is in Switzerland with branch offices in California, Florida, United Arab Emirates, and China. They have a bevy of investor and shareholders. It could be just me but, I think they are pretty serious. Maybe, I should talk to them about investing in inexpensive and routine access to space a la the Space Track Launch System. I personally don't think SBSP is the answer but, I'm not going to turn down a paying customer.

   Lets look at mining helium 3 on the moon. Google mining helium 3 on the moon. Let me point out a few of the first page topics:

   - Wikipedia, ditto

   - Dec 7, 2004 - "An Apollo astronaut argues that with its vast stores of nonpolluting nuclear fuel, our lunar neighbor holds the key to Earth's future." This is a Popular Mechanics article. Not generally considered a scientific journal but yet usually very informative on down to earth issues.

   -  "Mining the Moon. Lab experiments suggest that future fusion reactors could use helium-3 gathered from the moon. Thursday, August 23, 2007; By Mark Williams ..." This is a Technology Review article at www.technologyreview.com/Energy/19296/.

   - Dec 15, 2006 – "The Council is chaired by Apollo 17 astronaut Harrison Hagan "Jack" Schmitt, a leading proponent of mining the moon for helium 3. Schmitt ..." The quote is from Wired at www.wired.com/science/space/news/2006/12/72276?currentPage...

   - Mar 22, 2006 – "Russia To Mine Helium-3 on the Moon by 2020. According to an official statement released in January, the mining of helium-3 on the Moon will ..." The quote is from www.ufodigest.com/helium3.html. If Russia is going to do it, we better do it to.

   I don't want to go through it here but you might check out inertial electrostatic confinement fusion research at the University of Wisconsin and MIT. Their primary choice of fusion material is helium-3 which does not exist in a free state on earth. Also, I believe the University of Wisconsin is working on extraction techniques. The concentration of helium-3 on the moon is so small, you need hundreds of processors massing several metric tons each. I think they will be happy with economical and routine access to space a la Space Track Launch System.

   Is it commercially viable? It is estimated that helium-3 has a market value of over $15 trillion per metric ton (1997, J.S.Lewis, Mining the Sky). This is not only a noble cause but more importantly a high profit margin even for commercial launch systems.

   The near earth asteroid Amun is about 2 km in diameter and has a mass of approximately 30 billion tons (1997, J.S. Lewis, Mining the Sky). Assuming a typical iron composition, the asteroid has an iron and nickle content worth $8 trillion, a cobalt content worth $6 trillion, a platinum group content worth $6 trillion, and together with its nonmetallic components, the total market value of Amun is well over $20 trillion. I like John Lewis' idea of turning the asteroid into Swiss cheese by mining out the strategic metals, getting rich, and saving the planet at the same time. Is this a great country or what?

   There is a great many opportunities in space. Getting there is the problem and that is why I'm working on the Space Track Launch System.
« Last Edit: 01/10/2012 12:35 AM by Jerry Fisher »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #16 on: 12/13/2011 08:20 PM »
Have a look at this...

http://www.infoblog.us/2010/12/nasa-adds-turbojets-and-rockets-to-its.html

Thanks for the link. It's nice to keep up with the competition. Competition is good.

Jerry

Offline Jim

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Re: Space Track Launch System
« Reply #17 on: 12/13/2011 08:28 PM »

   I could go on about space colonization but I'm getting writers cramp. Google it yourself and you will find that you are in the minority concerning your comment on technical and commercial viability. There is a great many opportunities in space. Getting there is the problem and that is why I'm working on the Space Track Launch System.



No, not true. 
A.  You can always get more hits on pros for subject vs cons
b.  Science fantasy even gets more hits that all of yours combined.

1.  Terrestrial solar power will always be cheaper and more viable than SBSP.  There will never be an economic justification for SBSP.  There is enough barren land on the earth.
This is the majority opinion.

2.  helium-3 is still useless on earth.  They are no closer to fusion with it now as they were 30 years ago

3.  mining asteroids for terrestrial use is not viable either.  Getting the material to the surface is where is fails.  Mining asteroids is for ISRU and building hardware not intended to go back to the earth's surface.





« Last Edit: 12/13/2011 08:30 PM by Jim »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #18 on: 12/13/2011 08:42 PM »
how about this:

http://electrictakeoff.com/
Again, thanks for the link. I've done a few back of the envelope calculations based on the information in the article and it seems that at the point where the payload is removed from the hardness and attached to the ribbon, the resulting acceleration (i.e. the square root of the sums of the square of gravitational acc. and centrifugal acc.) retards the motion up the ribbon. In other words, the payload will begin to come back down the ribbon. I'll need more info to be sure. Its nice to keep up with the competition.

Jerry

Offline johncarpinelli

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Re: Space Track Launch System
« Reply #19 on: 12/14/2011 05:25 AM »
Hi Jerry,

I like the Space Track Launch System proposal. I hope the concept gains traction and the technical feasibility can be proven. I think a flying prototype is a good way to publicize the idea and prove some of the principles.

I am an engineer working on the electric takeoff project. The payload is an aircraft with wings. The payload should generate lift as it releases from the harness and transitions to the climb on the ribbon. At the transition point, it will be travelling as fast as the tow aircraft (e.g. Mach 0.4). Our initial goal is point-to-point transport so the glide ratio for the payload should be high.

As the payload climbs to higher altitudes the aerodynamic lift from the wings will be reduced due to lower atmospheric density, but the angle of climb on the ribbon should be lower to compensate. The ribbon flies as a wing at the highest possible altitude supported by its lift.

Both the velocity of the payload and the centripetal force will increase with greater radius. The system parameters are flexible and should be adjusted to allow a continuous climb up the ribbon using a combination of forces. To calculate the net forces on the payload, you need to consider the following:
-centripetal force
-gravity
-drag
-aerodynamic lift
-the reactive force from the ribbon

It's not an easy system to model. Let's continue the discussion and hopefully collaborate on some of the technical work.

Coincidentally, I published a short piece on inflatable space towers a few days ago on our site (http://electrictakeoff.com/blog). Would it be possible to build a space tower using a pyramid of inflatable spheres strapped together? Would that reduce the strength requirements for the construction material?

John

Offline RanulfC

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Re: Space Track Launch System
« Reply #20 on: 12/14/2011 04:17 PM »
But to your "basic" question of the concepts technical feasiblity; of course it's "feasible" and could "technically" be done. I've actually seen this same idea several times before though your suggestion of counter-weights and launching from the mid-point of the teather is an interesting variant that mitagates some of the difficulties with earlier suggestions, so further work is certainly useful.

First, let me apologize for my Randy rant. That is not the way I would like this topic to go.
What "Randy-rant"? I've been "schorched" worse by off-handed commments on these boards! Your fine :)

Quote
However, to so cavalierly dismiss my concept as an interesting variant on an earlier idea is condescending. The fact that the second stage launch vehicle is launched from the middle of the ribbon, the fact that the overcarriage remains on the ribbon providing a retarding force, and the fact that the counterweights absorb the shock and dampen the oscillations make this concept possible.
I did NOT mean to "demean" or act "condescending" in the aforementioned statements and I apologize for any such misconception, I was mearly pointing out that I'd seen similar proposals before and that yours at least seems to try an address some of the concerns with the system :)

I'll note that the majority of "previous" concepts I'd seen were more similar to "pellet" mass-driver concepts in opertion. A LOT of 'handwaving" was apparent given how they didn't really address how you got your "payload" from a position within a non-rotating town into a rotating section , aligned with the "launch-tube" and then launched.

At least you address these points :)
Quote
In my concept, launch is possible again after eight hours. But is it technically feasible? That is what I hope to answer with intense technical debates on this forum and through my web site at www.fisherspacesystems.com.
I'm hoping to see that myself. Hopefully instead of one or two sentenc "answers" simply  stating "it won't work" or "It will cost to much" etc... :)

As for our philosphical differences I'll only say I'm not pointing out the current situation as an example of FUTURE expectations but I'm saying that this is the point we are at, and the difference between now and future needs isn't really something that simply can be assumed.

You (as do all folks coming up with launch concepts, me included) have to keep in mind that while you have an "optimized" payload ability that makes your system economic and efficent, there is going to have to be a method or plan for getting up to that level from our current levels and THAT particularly is a very tricky situation to address.

Finally, "my" particular and often semi-obsesive (being nice about it :) )"peeve" as an ex-Air Force maintainer is operations and maintenance of the concept. Now I'm NOT going to ask for an in-depth study and planning of how someone would change a light-bulb on the tip of the teather while it's rotating or anything like that. At this stage overall functionality and technical feasability are of course more important. However consider this your "warning" of sorts that "I might actually come back at some later point and actually ask for some more details :)

Currently I'm still working on reading through the materials given.

Thanks for listening,

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 Jerry Fisher

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Re: Space Track Launch System
« Reply #21 on: 12/15/2011 08:25 PM »

I am an engineer working on the electric takeoff project. The payload is an aircraft with wings. The payload should generate lift as it releases from the harness and transitions to the climb on the ribbon. At the transition point, it will be travelling as fast as the tow aircraft (e.g. Mach 0.4). Our initial goal is point-to-point transport so the glide ratio for the payload should be high.

It's not an easy system to model. Let's continue the discussion and hopefully collaborate on some of the technical work.

   A payload with wings. That explains the extra acceleration component. Mach 0.4 is about 121 m/s at 30,000 ft. That is a reasonable speed. Military turbo props can do a maximum of 260 m/s but that is at a lower altitude.

   The modeling sounds like a nightmare. I tried integration but there are just to many variables. I initially did the modeling with a spreadsheet but, had to assume a rigid ribbon. That is okay for a second generation tower with a CNT ribbon and a 200 ton counterweight but not okay for a first generation tower with a Spectra ribbon and a 25 ton counterweight. I have to use a flexible ribbon model. So, I've resorted to numerical analysis with a FORTRAN program in 100m steps. I'm still working on it. I've had to put it aside as other things have come up. I'm updating my concept paper on second stage requirements. Do you assume a rigid ribbon from the hub to the tow aircraft? If so, what is the angle the ribbon makes with the horizontal and the angular velocity?

Coincidentally, I published a short piece on inflatable space towers a few days ago on our site (http://electrictakeoff.com/blog). Would it be possible to build a space tower using a pyramid of inflatable spheres strapped together? Would that reduce the strength requirements for the construction material?

   It looks like a good approach. I like the individual cell approach as opposed to my 10 km long gas bag approach. I like the fact that it is free standing as opposed to guy wires. It could be made safe with redundant spheres. But, eventually you'll have to replace some or bring down the tower for maintenance. Thanks to Airman Basic Murphy, if a sphere fails it will probably be 50 km up and in the middle. So, my question is how will you maintain the tower? As far as the strength requirements go, I think no matter what approach we take the strength requirements will be stretched to their limits (pun intended).

   I've tried to keep maintenance and repair in mind as I designed my concept. For example, my tower is designed such that five of the six towers can support the load. If one section of one tower is leaking hydrogen excessively, I'll cease operations and take the cargo elevator up to the leaking gas bag, collapse it, take it out of the sleeves, replace it with a new bag, inflate it, and resume operations. In fact, I'll probably do that remotely (my daughter is going into bio-mechanics). However, if we put gas cells in each 10 km section (a la 5 m spheres), it sounds like a more stable tower. What do you think?

   I am ready to collaborate. Collaboration is good but, mass collaboration is better. Hopefully, we can draw a few more people into the technical discussions.


Offline krytek

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Re: Space Track Launch System
« Reply #22 on: 12/15/2011 09:01 PM »

   I could go on about space colonization but I'm getting writers cramp. Google it yourself and you will find that you are in the minority concerning your comment on technical and commercial viability. There is a great many opportunities in space. Getting there is the problem and that is why I'm working on the Space Track Launch System.



No, not true. 
A.  You can always get more hits on pros for subject vs cons
b.  Science fantasy even gets more hits that all of yours combined.

1.  Terrestrial solar power will always be cheaper and more viable than SBSP.  There will never be an economic justification for SBSP.  There is enough barren land on the earth.
This is the majority opinion.

2.  helium-3 is still useless on earth.  They are no closer to fusion with it now as they were 30 years ago

3.  mining asteroids for terrestrial use is not viable either.  Getting the material to the surface is where is fails.  Mining asteroids is for ISRU and building hardware not intended to go back to the earth's surface.






Be careful, you might end up on this list Jim
http://listverse.com/2007/10/28/top-30-failed-technology-predictions/

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #23 on: 12/15/2011 09:02 PM »
No, not true. 
A.  You can always get more hits on pros for subject vs cons
b.  Science fantasy even gets more hits that all of yours combined.

1.  Terrestrial solar power will always be cheaper and more viable than SBSP.  There will never be an economic justification for SBSP.  There is enough barren land on the earth.
This is the majority opinion.

2.  helium-3 is still useless on earth.  They are no closer to fusion with it now as they were 30 years ago

3.  mining asteroids for terrestrial use is not viable either.  Getting the material to the surface is where is fails.  Mining asteroids is for ISRU and building hardware not intended to go back to the earth's surface.

  Science fantasy has given us a lot of good ideas. 1945 Clarke, geostationary satellites, flip up cell phones and medical scanners, Star Trek, Space Elevators, Clarke again.

  By the way, if anyone has read a science fiction or science fantasy book covering my concept, I would be interested in reading it. I've been looking for 8 years and haven't found anything.

  You might want to talk to Donald Trump about terrestrial solar power. He has looked into powering some of his buildings with solar power. It takes 20 years to recover the cost and they fail in 10. How is that justifiable.

  ITER is a political bureaucratic nightmare and that is where all of the research money goes. Magnetic confinement fusion is very complicated. Every time they add a magnetic coil to take care of a plasma instability, two more instabilities take its place. Kind of like a hydra. And yes, they have been promising fusion in 50 years for the past 50 years.

  Inertial Electrostatic Confinement is the way to go. Many universities are experimenting, University of Wisconsin and MIT to name a few. Research budgets are low but you can build one in your basement and demonstrate fusion. If it is cheap to do research, then a lot of researcher will do it if only for the education and fun (I want to build one in the basement but my wife won't let me). Someone, someday will have an a ha moment and cheap reliable table top fusion will be born. I'll stake my reputation on it (I don't really have much of a reputation so don't quote me). Besides, once I get into space, I'm going to tackle IEC fusion. Space is a perfect place and besides it is out of the basement.

  Granted most of the materials mined from asteroids will be ISRU. But, that makes it commercially viable doesn't it? However, finding and processing strategic materials on earth is getting harder. The only other option is to process the minerals from the sea. So a more appropriate comparison for economically viability would be to compare in space mined and processed strategic materials leftover from ISRU at a substantially marked up value to filtered and processed strategic materials from the sea. Wouldn't that make it commercially viable?
« Last Edit: 12/24/2011 02:13 PM by Jerry Fisher »

Online Robotbeat

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Re: Space Track Launch System
« Reply #24 on: 12/15/2011 09:34 PM »
Helium 3 isn't useless. It's used for neutron detection and medical lung imaging today and can fetch prices of up to $2000/liter, which (at He3's low density of ~13.5 grams/liter) means up to $150,000 per kg. Then again, the total US consumption is only for about 800kg per year.

But I hear ya. Fusion is a neat idea, but I actually think fission is a lot easier and cheaper and can be made basically just as clean as He3 fusion. And we're decades away from usable extra power from fusion, anyway (I'm rooting for laser-induced inertial confinement fusion these days). I don't really think mining it from the Moon will make sense in my lifetime. Seriously, just think about how much regolith you'd have to sift in order to get a usable amount of helium-3...
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #25 on: 12/15/2011 09:47 PM »
Finally, "my" particular and often semi-obsesive (being nice about it :) )"peeve" as an ex-Air Force maintainer is operations and maintenance of the concept. Now I'm NOT going to ask for an in-depth study and planning of how someone would change a light-bulb on the tip of the teather while it's rotating or anything like that. At this stage overall functionality and technical feasability are of course more important. However consider this your "warning" of sorts that "I might actually come back at some later point and actually ask for some more details :)

  Bring it on Randy :) I'm an ex-Air Force maintainer as well, Strategic Air Command. So, lets talk maintainability. There are 160 counterweights (80 on each side). Not only do the counterweights deploy the ribbon and actively dampen shock and oscillations, they can roll up the ribbon for replacement. Don't get me started on the 160 high powered solid state lasers plus spares on the ground and the high efficiency Gallium Arsenide photovoltaic cells on the counterweights required to do this.

  The beams, columns, and struts on the turntable can be inspected on a regular basis and repaired as required. Unfortunately, composites fail differently than metals and often castrophically. Thus a safety factor of 8 in the design.

  The 20 gear sets act independently and can be replaced if there are excessive teeth missing. The super conducting electric motor is assessable and can be removed and replaced. Elevators, no problem.

  There are six inflatable towers. The interface ring is designed to support the load with only three inflatable towers. However, if two adjacent towers fail there could be a problem. The inflatable supports come in 10 km sections. If one section shows excessive hydrogen leaks, I'll cease operations, take the elevator to the appropriate section, deflate it, remove it, replace it, and re-inflate it, and go back operational.

  All this takes time and money of course. The details can be worked out but, I believe it is possible.

Jerry
« Last Edit: 12/24/2011 05:28 PM by Jerry Fisher »

Offline johncarpinelli

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Re: Space Track Launch System
« Reply #26 on: 12/17/2011 04:22 PM »
Jerry,

The reference design for electric takeoff system uses a 10km altitude and 4km radius for the tow aircraft. This gives an angle of 68 degrees for the initial climb. You can look at the economics of the system for aviation at the link below.

https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0ArN3BBRS37YcdHVkTGN0dl81NWFFSDdWcDBaTDd0MlE&single=true&gid=0&output=html

I confidently predict that 99% of the readers of this forum will never fly to space in a rocket. Even if Stratolaunch, Virgin Galactic and SpaceX succeed with their technology development, it will still be too expensive for the middle class to fly. Optimistically, sub-orbital flights might sell for $30k in 2020, but most middle class tourists cannot justify that expense for five minutes of space flight.

I predict that 99% of forum readers will ride an electric elevator to the top of a tall building and look out the window. This is a low cost tourist activity. I have been to the top of the Space Needle in Seattle and enjoyed the experience. Inflatable space towers are an extension of this concept.

So if you are a skeptical space enthusiast then think realistically about  your future options for visiting space. If you want to see the curvature of the Earth first hand and experience a weightless re-entry back to Earth, your best hope is a space tower.

John

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #27 on: 12/19/2011 01:52 AM »
John

  Thanks for the info and the link. I'll look the economics over and get back to you.


So if you are a skeptical space enthusiast then think realistically about  your future options for visiting space. If you want to see the curvature of the Earth first hand and experience a weightless re-entry back to Earth, your best hope is a space tower.

   I think of myself as an optimistic space enthusiast. I prefer to think of the glass as 1% full as opposed to 99% empty. There are over 300 million people in the US today. Lets say 1% are wealthy Americans. That is 3 million people. Lets say that 1% of those are extreme adventurers and would pay for a trip into space. That is 30,000 people. Launching 12 people a day (1 pilot and 5 paying customers and 2 launches) would take 3,000 days. At 5 days a week and 50 weeks a year (excluding weekends and holidays, of course), that is 12 years to satisfy the customer demand. That does not include any down time for the tower and repeat customers. I may need two towers to meet the demand.

   Now some of those extreme adventurers may want to stay in space for more than 3 or 4 orbits (approximately 8 hrs). There has to be a place to go and guess what, Bigelow Aerospace has just launched a nice hotel and convention center on a Falcon Heavy Lifter and the accommodations are reasonably priced. The staff must rotate every month or so to avoid any potential health problems associated with long term weightlessness (new OSHA standards). Fuel and supplies have to be taken to the hotel on a periodic basis. All provided by the Space Track Launch System and Fisher Space Systems, LLC at a reasonable cost (TBD).

   With the exception of satellite launches, I believe that tourism will lead commercial industry into space. Throughout history, commercial industry lead tourism. Tourism came after there was a place to go, something to see, and a place to stay. Take Ft. Lauderdale for example. I lived in Ft. Lauderdale, FL when I was in kindergarten in 1960. A day at the beach was with family and friends. A barbecue and beach volleyball. The beach was virtually empty. Maybe a few other families. We lived in Ft. Lauderdale for the weather (my mother's health) and the jobs (my dad was a jet engine technician). We maybe saw a few tourist. You could always pick them out because no one knew them. The weather and jobs were the big attraction. Now, you can't even walk on the beach without stepping on some beach bum or beach bunny sunning himself or herself and don't even try to drive down Rt 1 on a Saturday afternoon. In the past, tourism always followed commercial industry. I believe the opposite is true for space. Tourism (with the exception of satellite launches) will be the industry for the immediate future then commercial industry will take hold.

   Lets get more enthusiastic here. The glass is 1% full not 99% empty.

Jerry
« Last Edit: 12/24/2011 05:33 PM by Jerry Fisher »

Offline Jim

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Re: Space Track Launch System
« Reply #28 on: 12/19/2011 02:32 AM »

   I think of myself as an optimistic space enthusiast. I prefer to think of the glass as 1% full as opposed to 99% empty. There are over 300 million people in the US today. Lets say 1% are wealthy Americans. That is 3 million people. Lets say that 1% of those are extreme adventurers and would pay for a trip into space. That is 30,000 people.

Both assumptions are too high.    People who want to and can afford are less than 5000.

Offline Jim

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Re: Space Track Launch System
« Reply #29 on: 12/19/2011 01:12 PM »

Both assumptions are too high.    People who want to and can afford are less than 5000.

  Maybe. Maybe not. I haven't done a detailed cost analysis. If I don't achieve at least an order of magnitude reduction in launch cost at the start, then I can't justify even building the Space Track Launch System. If I do achieve an order of magnitude or better, than I would expect the 5000 number to go up.

  By the way, I showed you my assumptions. I'd like to see yours. Where did you get that number and what is it based on? Surely, it is not a WAG.

Jerry

Look at SpaceShip2 reservation list length

Offline JohnFornaro

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Re: Space Track Launch System
« Reply #30 on: 12/19/2011 02:36 PM »
Quote from: OP
The system consist of counterweights attached to ribbons which are attached to a rotating truss mounted on a tall tower...

I almost stopped reading, but I'll bite:

Too complicated.  Save your limited future time, and learn to finesse chemical rocketry.

Quote from: Andrew
The "when it is 2 magnitudes taller than anything ever built?" isn't relevant, like all the creative alternative ideas it comes down to: Is it possible, what's the cost, and who's going to foot the bill?

You answered your own question:  What's the cost when the structure would be about a hundred times taller than any static structure ever built?  I know, with God, all things are possible; but this one's on Jerry.  Just because you don't get it... Oh.  I see.

Quote from: Jerry
What aerospace company wants to operate out of the north pole?

A practical consideration of little pertinance.  Before it was known for sure that there was water ice on the Moon, it was known that water would be crucial for a lunar base.  For about a paragraph or two, I suggested using boom boom Orion to launch water ice up to the base.  From Antarctica.

Quote from: Jerry
The material of choice is a carbon nanotube material with a working tensile strength of 25 GPa....

... the manufacturing of which has not been demonstrated for anything of this size and complexity.  Further, compressive and torsional loads at the foundation are equally as important, tho not nearly as glamorous, and have not been considered sufficiently.

Quote from: Jerry
A detailed cost analysis has not been done. The first task is to determine if the STLS is technically feasible.

You have not demonstrated anything on your website about feasibility, although you have demonstrated some 3D CAD skills which are greater than mine.  The only technical feasibility you have given shrift is that of the carbon nanotube.  Using perhaps ten or so 8 1/2 x 11 pieces of paper, you could consider a more well rounded assessment of the necessary sub-systems involved.  To suggest a  GOCO arrangement is to demonstrate that you are writing contracts before you even know where the horse and the cart are.

Regarding the chicken and egg aspects of the problem you have set for yourself, when you suggest six tons a day each day of the year, it is evidence that you have not considered DDT&E, of which time is of crucial importance.  In the case of your proposal, perhaps a hundred years to that capacity, should you convince Congress, might be a place to start.  Taking six tons at face value, you must also acknowledge that the passenger load in a fully functioning system would be maybe two a day, at best, and presupposes sufficient waiting facilities for those passengers.

In addition, this thread is an informal peer review, FWIW.

Quote from:  Jerry
I have looked into ... transferring momentum to the launch vehicle. Launching from the tower and attaching to a tether in LEO will greatly reduce the deltaV required from the launch vehicle. It turns out that the payload capability is about doubled.

You have now introduced a tether, which does not simplify anything except for a simple calculation of angular momentum.  There is no demonstration of doubling anything, except a series of numbers on a page.

Quote from: Randy
The point ... would probably be better stated as asking:  Given the mega-structure of the tower and tethers, the infrastructure, and all the associated overall costs involved how does your concept help get from where we are not to where your concept becomes "cost-effective" in terms of launch capacity and price per-pound-to-orbit?

That is correct, young Paduan.

Quote from: Jerry
I've seen the government uhhhh.... taxpayer get screwed so many times on cost plus fixed fee contracts it ain't funny...


Little typo there.

Quote from: Jerry
However, I don't have $25 million for a few days on the ISS.

Being the modest, hi-flyin' trillionaire playboy that I am, I sympathize with the 99%.  Truly, I say unto you.

Quote from: Jerry
Otherwise, I don't have the time or the patience to listen to age old arguments about cost. We will get to that point if the concept is feasible and we have a better handle on the technology.

I always use the UBS myself.  Cost must be considered in broad brush terms at least.  That is part of feasibility; the concept is not feasible.  I've mentioned several ways already.

Quote from: Jerry
The fact tentative suggestion that the second stage launch vehicle is launched from the middle of the ribbon, the fact tentative suggestion that the overcarriage remains on the ribbon providing a retarding force, and the fact tentative suggestion that the counterweights absorb the shock and dampen the oscillations make this concept theoretically possible.

If I were writing the sentence, that is.

Quote from: Jerry
Webster's dictionary defines paradigm as a philosophical or theoretical framework of any kind. Your comment is definitely not theoretical so it must be philosophical in nature. So let's talk philosophically.

Webster's Seventh New Collegiate, here.  You are spot on philosophically about the need for American society to seriously consider what it wants to do when it grows up.  But your system still cannot be made to work, and cannot therefore work to change the nation's philosophical bent.  You are talking about the journey of a thousand miles, but you haven't yet demonstrated taking the first step.

Quote from: Jerry
Lets take space based solar power satellites for example. Goggle space based solar power. You will get approximately 217 thousand hits.

Absolutely not.  Space based solar power, from an orbiting lunar constellation, directed at the base, might work.  But not at all thru Earth's atmo.  In addition, He3 has absolutely no market for the next hundred years here.  Finally, the number of hits from the game based googol network, is simply a count created by computer system with virtually no intelligence; the statistic is virtually meaningless per the Shannon definition.  Jim is not "denigrating science fantasy", he is saying that the statistic has no value; if you think it does, then your project will certainly fail, since physics is not a gamed popularity contest.

However, you are absolutely correct in that, "Getting there is the problem".  And also about the glass being 1% full.
Sometimes I just flat out don't get it.

Offline johncarpinelli

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Re: Space Track Launch System
« Reply #31 on: 12/19/2011 10:34 PM »
We taxpayers have spent sixty years and hundreds of billions trying to "finesse chemical rocketry". As a result, we can now purchase $35m tickets to orbit on a foreign rocket. It is not an ideal situation. We have been told that mass market space travel is always a decade or two into the future. Perhaps rockets are the wrong solution?  They are great for billion dollar flags and footprints missions, but maybe they are not suitable for mass transportation.

As a taxpayer, I would prefer to fund systems that can take me on safe suborbital space trips for less than $1000 per passenger. My rough cost estimate for a inflatable space tower to 100km is between $650 million and $2 billion based on material costs at $1000 per ton. This is just a ball-park estimate, but it is well within the resources of several government space agencies.

We should restrict space tower research to currently available materials like Spectra. We should not assume that carbon nanotubes will be available in the required lengths any time soon.

Building a prototype tower to 300 feet would be a nice way to gain credibility for this project. Hobbyists have been building rockets for decades and it would be nice to see some amateurs working on towers also.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #32 on: 12/20/2011 02:16 AM »

   Further, compressive and torsional loads at the foundation are equally as important, tho not nearly as glamorous, and have not been considered sufficiently.

   Compressive loads at the base are covered in the concept paper on the tower. Torsional loads at the base are not. Thank you for pointing that out. It is an oversight on my part which I will correct in the next update.

Quote from: JohnFornaro
You have not demonstrated anything on your website about feasibility, although you have demonstrated some 3D CAD skills which are greater than mine.

   True. I have not demonstrated feasibility on my website. That is not the purpose. The purpose is to debate technical feasibility. If you noticed, each page that covers a subsystem has a comment section and an email form. Feel free to add your technical criticisms there and I will strongly debate you. As far as the 3D CAD skills go, you ain't seen nothing yet.

Quote from: JohnFornaro
   Regarding the chicken and egg aspects of the problem you have set for yourself, when you suggest six tons a day each day of the year, it is evidence that you have not considered DDT&E, of which time is of crucial importance.

   Okay, six tons a day each day of the year maybe stretching it a little but, this is a possible operational scenario. By this time, the DT&E has already been done. True. Some downtime will be necessary for upgrading the system and more T&E will be required. By the way, I know DT&E stands for developmental, test, and evaluation but, what is DDT&E? Did someone change the acronym and if so, why wasn't I informed?

Quote from: JohnFornaro

   In addition, this thread is an informal peer review, FWIW.

   True again. But, I gotta start somewhere.

Quote from: JohnFornaro
I've seen the government uhhhh.... taxpayer get screwed so many times on cost plus fixed fee contracts it ain't funny...


  True again. However, as a captain in the Air Force and responsible for the peoples money, I took it personally when the government of the people, by the people, and for the people got screwed.

Quote from: JohnFornaro

   The fact tentative suggestion that the second stage launch vehicle is launched from the middle of the ribbon, the fact tentative suggestion that the overcarriage remains on the ribbon providing a retarding force, and the fact tentative suggestion that the counterweights absorb the shock and dampen the oscillations make this concept theoretically possible.

The idea that the second stage launch vehicle is launched from the middle of the ribbon, the idea that the overcarriage remains on the ribbon providing a retarding force, and the idea that the counterweights absorb the shock and dampen the oscillations make this concept theoretically possible.

Is that better?
« Last Edit: 12/24/2011 02:21 PM by Jerry Fisher »

Offline johncarpinelli

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Re: Space Track Launch System
« Reply #33 on: 12/21/2011 05:19 PM »
We taxpayers have spent sixty years and hundreds of billions trying to "finesse chemical rocketry". As a result, we can now purchase $35m tickets to orbit on a foreign rocket. It is not an ideal situation.

Which is true about the poor, ever suffering taxpayer, but false about the conclusion you draw.  True, in general, that the current status of our HSF program is the result of chemistry, but it is the result caused by political chemistry, not the chemistry of the rocket equation. 

Politics are not the whole explanation for the high launch costs for rockets. Consider the private rocket companies that have tried and failed to deliver on cheap launchers. Kistler, Rocketplane and Rotary Rocket were the last generation of failures. Now, we have a new set of rocket companies that are yet to deliver affordable space transport. No-one is even talking about a $10,000 ticket to orbit that would be accessible to the middle class.

To lower launch costs, we need a system that amortizes its cost over many journeys and can generate revenue from both aviation and space transport. Suitable technologies include laser launch, tether launch and space towers. The system should earn revenue after a modest investment and not require billions of dollars in development upfront. A small space tower or tether launch system could start earning tourist dollars with joy rides to 10,000 feet or lower. The system must have safety and reliability comparable to today's aviation industry also.

In the case of electric takeoff, most revenue would be generated from point-to-point air transport for passengers and freight. Space launch would be supplemental income. This would allow orbital launches to be cheap because the capital costs of the system would be repaid through aviation revenue.

It seems that the space industry is too busy building government funded rockets to bother with these alternative launch schemes. The most likely scenario is that space travel will remain a hobby for billionaires and nationalistic governments, while the rest of us sit on the sidelines and spectate. I am not happy with this future, but there seems to be little interest in developing something better.

Offline Jim

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Re: Space Track Launch System
« Reply #34 on: 12/21/2011 09:35 PM »

To lower launch costs, we need a system that amortizes its cost over many journeys and can generate revenue from both aviation and space transport. Suitable technologies include laser launch, tether launch and space towers

Wrong.  There is nothing that says those technologies are suitable, viable or even possible.

If launch costs are to be lowered, it is not going to be with a system that requires 100's of billions of infrastructure.

Electric takeoff is just another unworkable scheme promoted by the fringe.

« Last Edit: 12/21/2011 09:36 PM by Jim »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #35 on: 12/22/2011 10:14 AM »
   Correct me if I'm wrong but, I believe this is NASASpaceFlight's forum on advance concepts. It appears a few other ideas of advances in propulsion is a .01% increase in chemical propellant efficiency (I believe someone used the term finesse). So, lets get back on topic.

   The basic idea behind the Space Track Launch System is simple. If you take some fishing line (Spectra makes a good high strength line and it's tolerant to UVs), tie a heavy rock at one end, and swing it around your head, you have the tower, ribbon, and counterweight concept.

   Now add a paperclip (spaceship) to the line such that it begins its motion at your hand. Give it a little push and the paperclip will accelerate down the fishing line toward the rock. From your perspective (i.e. looking down the line), it appears that the paperclip moves straight down the line. The acceleration is a result of the gravitational acceleration and centripetal acceleration acting on the paperclip. From an observers perspective (i.e.  looking at the person swinging the rock), the paperclip takes a spiral route.

   Gravitational acceleration is constant. Centripetal acceleration is a function of the radial distance from the axis of rotation. As we all know, an acceleration produces a change in velocity. Therefore, the radial velocity is increasing with radial distance.

   That is not the only velocity changing. As the radial distances from the axis of rotation increases, the tangential velocity increases (i.e. the velocity perpendicular to the line). A change in velocity over time is an acceleration. That acceleration is the acceleration due to the Coriolis force. The vector sum of all the accelerations is the total acceleration experienced by the paperclip (spaceship). If at some point along the line the paperclip comes off (launches), the launch velocity is the vector sum of the radial velocity and tangential velocity at the launch point.

   Now scale this up a gazillion times and you have it. The basic idea behind the Space Track Launch System. By the way, if you try the above experiment, wear gloves. That fishing line will cut through your fingers.

« Last Edit: 12/24/2011 05:37 PM by Jerry Fisher »

Offline Jim

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Re: Space Track Launch System
« Reply #36 on: 12/22/2011 11:46 AM »
If launch costs are to be lowered, it is not going to be with a system that requires 100's of billions of infrastructure.

Electric takeoff is just another unworkable scheme promoted by the fringe.

As with current launch systems like NASA and the Space Shuttle infrastructure.

I'm on the fringe and proud of it. At least I'm trying to do something about the high cost of spaceflight.

Jerry

No, Space Shuttle was not 100's of billions, only 10's of billions and current vehicles are much less.

Trying?  More like just writing science fiction.

1.  anything needing 100's of billions of infrastructure is not going to be built
2.  anything needing 100's of billions of infrastructure is not going to reduce costs.

3.   anything needing 100's of billions of infrastructure is going to have O&M costs in the billions

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Re: Space Track Launch System
« Reply #37 on: 12/22/2011 11:51 AM »
   Sorry folks. It seems I've let a few chemical propellant advocates (I'll call them CPAs from now on) hijack my topic. Correct me if I'm wrong but, I believe this is NASA's forum on advance concepts. It appears the CPA's idea of advances in propulsion is a .01% increase in chemical propellant efficiency (I believe someone used the term finesse). So, lets get back on topic.


A. It will take a new power source to make an advance in space launch, not more infrastructure.

B.  This is not "NASA's" forum.  This is "NASASpaceflight.com" privatly run forum.

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Re: Space Track Launch System
« Reply #38 on: 12/22/2011 03:32 PM »
From:

http://www.fisherspacesystems.com/stlsweb1_002.htm

Quote
The Space Track Launch System (STLS) is a two stage system. The first stage is a tall tower 100-150 km high.

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.

From:

http://www.fisherspacesystems.com/stlsweb1_003.htm

Quote
The second stage is a liquid fueled launch vehicle (LV) designed to launch form the STLS. The launch vehicle attaches to a generic overcarriage.

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.

From:

http://www.fisherspacesystems.com/stlsweb1_004.htm

Quote
The overcarriage is itself a reentry vehicle.

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

From:

http://www.fisherspacesystems.com/stlsweb1_005.htm

Quote
The counterweight is designed to deploy a thin layer of ribbon approximately 400 km long. During deployment, the motor produces approximately 60 kW of power which is dissipated through nichrome wires at the base of the counterweight.

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.

Quote
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 pertinant to the idea of feasibility.  Here is a new power transmission scheme which has not been considered sufficiently.

From:

http://www.fisherspacesystems.com/stlsweb1_006.htm

Quote
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.

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

From:

http://www.fisherspacesystems.com/linked/stlsupdated10062011.pdf

Quote
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.

From:

http://www.fisherspacesystems.com/linked/stlsovercarriage.pdf

Quote
Finally, the overcarriage returns to the launch site, making the STLS a completely reusable launch system.

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.

Quote
For an 80 ton launch vehicle under a 6g load, each ejector segment supports a load of 2.4 x 106 N. The ejector segment is made of 60% Carbon Fiber and 40% Epoxy.  This gives an ultimate strength, σu, equal to 1.47 x 109 N/m2 and the modulus of elasticity, E, equal to 1.38 x 1011 N/m2.

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.

Quote
The air bearing must produce a total lifting force of 1.5 x 106 N.

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.

Quote
The fuselage for the overcarriage is of a conventional aircraft design.

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

Quote
It is assumed that the hydraulic system can use the same nitrogen gas that is used for the air bearings.

An assumption without justification.

From:

http://www.fisherspacesystems.com/linked/basic%20tower%20design.pdf

Quote
A base load of 8.0 x 107 N over an area of 12.6 m2 results in a load per unit area of 6.4 x 106 N/m2 or about 921 psi.

This is an inadequate foundation analysis.

Edit:  BTW, I read every page on the website.  I did not check any of the calculations, since there was no need.  The level of detail in the calcs tended to apply to small problems within the scheme in general, while the integration of the many sub-systems needed for the scheme to work were not considered at all. 

The assembly of the system is of crucial importance.  There was no overview at all of how such an enormous system, encompassing the volume of a cylinder 150 km tall and 400km in diameter, would be constructed from the ground up.  The few calculations that I reviewed more than cursorily, particularly the centripetal forces of the rotating device in its final configuration, presupposed a completely erected, fully functional system.  There was no consideration being given to the inevitable windloads and the considerable instabilities that would be imposed on the structure, particularly before it was fully operational.

It appears that literally, the project would never get off the ground.
« Last Edit: 12/23/2011 02:32 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Online spacenut

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Re: Space Track Launch System
« Reply #39 on: 12/22/2011 04:42 PM »
The reason skyscrapers aren't built much taller than they are is because of the weight.  The pressure of the weight produces heat at the base because of molecules being pressed together.  Too much weight will cause the foundation to fail, unless it is built like a pyramid. 

They have already studied a maglev rail propulsion system.  Say about a mile or two long that would launch a SSTO space shuttle.  It only cuts about 20% of the fuel costs getting it to 600 mph at takeoff to avoid breaking the sound barrier at ground level. 

The only reasonable cost effective viable alternative is a TSTO with the first stage as a flyback or parachute back booster.  Launch rates would have to increase dramatically to make this a viable alternative. 

The space shuttle was reusable except for the tank, but refurbishing the boosters, and the orbiter after every flight for only a 20 ton useful payload to orbit was and is expensive unless if flew 10-12 times a year.  Existing 20 ton ELV's are far less expensive for the number of flights a year. 

Now if we built fuel depots in LEO, at L1 and a moon base, that requires constant fueling, maintenance, etc, then reuseable becomes more cost effective.  This is one way NASA could get continuous funding is by using existing rockets to build this infrastructure.  Like the ISS, it will be kept funded for 20 or more years, which gives us time to go to Mars.

While this is being done, Vasmr or Ion propulsion using solar or nuclear could be added to this in-space infrastructure.  Congress wouldn't allow us to abandon it. 
« Last Edit: 12/22/2011 04:45 PM by spacenut »

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.

Quote
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.

Quote
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.

Quote
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.

Quote
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.

Quote
    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.

Quote
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.

Quote
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.

Quote
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.

Quote
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.

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

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

Quote
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.

Quote
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 »

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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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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 »
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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:

Quote
(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.

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.
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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.

Offline 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 »

Offline 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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Re: Space Track Launch System
« Reply #80 on: 02/25/2012 11:04 PM »
Well I think you're off your rocker ....
  Probably, but since no one has convinced me that my physics is wrong, I'll continue on.

  I'm working on a first generation system that uses currently available materials. The ribbon material is either Spectra 2000 or Kevlar 49. Since the ribbon makes up the majority of the mass, I've had to introduce a new flexible ribbon model. Instead of a constant angle with respect to the axis of rotation as with a CNT ribbon, the ribbon has a definite curvature. In other words, each 100 m ribbon segment makes a slightly different angle with respect to the axis of rotation. The angle the ribbon makes with the axis of rotation has an impact on the tension in the ribbon, the mass of each ribbon segment, and the total mass of the ribbon. I've updated my web site. You can review the paper covering the flexible ribbon model by clicking on the concept paper link.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #81 on: 09/04/2012 12:19 AM »
I am proposing a 25 km proof of concept tower. Because of atmospheric heating the ribbon is only 2 km long. It is long enough to demonstrate most of the capabilities of the Space Track Launch System. The counterweight is about 25 metric tons and reels in and out for maintenance, repair, and down time. The second stage is a single place suborbital launch vehicle about the size of the Mercury capsule.  The tower is made of Kevlar inflatable beams 1.5 km long and 2 m in diameter. The beams mass about 10 metric tons each making maintenance, repair, and/or replacement possible. It is stabilized by four sets of guy wires radially out from the base about 14 km. There are 24 beams at the top and 600 beams at the bottom. Ground loading is about 200 psi. I've updated my website. For more details, visit www.fisherspacesystems.com, click on the concept papers button, and review the Proof of Concept pdf. Your comments are welcome.

Offline QuantumG

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Re: Space Track Launch System
« Reply #82 on: 09/04/2012 12:56 AM »
What's your cost estimate?
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 ptolemy1977

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Re: Space Track Launch System
« Reply #83 on: 09/04/2012 07:58 AM »
How do you propose building the tower when it is 2 magnitudes taller than anything ever built?

That's a good question. Much, much research and development is required for this to be feasible. For a second generation tower, the tower will be approximately 150 km tall and support an estimated 3,100 metric tons. The tower will precess since it will be located anywhere from 0o to 50o north latitude. (What aerospace company wants to operate out of the north pole?) IMO, a tower under tension is the only possibility. Several authors have theorized on the possibility of tall support towers (references below).

The analysis for the support tower relies heavily on the work presented in "Feasibility of a 20 km Free-Standing Inflatable Space Tower" by R. K. Seth, B. M. Quine, and Z. H. Zhu. For the case of a second generation system, the material of choice is a carbon nanotube material with a working tensile strength of 25 GPa. The tower would be filled with hydrogen from 20 km to 150 km and helium from 0 km to 20 km. The top 10 km of tower will have to be pressurized to 4.8 x 105 N/m2. The pressure will increase as more mass is added to the tower. The initial design of the tower is in 10 km increments for the hydrogen fill and 5 km increments for the helium fill. Guy wires will be attached to retard the precession. Unfortunately, due to the elasticity of the CNT cable, the tower will sway an estimated 10 km southward with a period of 4.4 minutes. Strong stomachs are advised.

References

Fisher, J.F., 2011, Space Track Launch System - Tower, www.fisherspacesystems.com

Smitherman Jr., D.V., 2000, Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium, MASA/CP-2000-210429

Seth, R.K., Quine, B.M., and Zhu, Z.H., 2009, Feasibility of 20 Km Free-Standing Inflatable Space Tower, JBIS, Vol. 62. pp. 342-353, 2009

Bolonkin, A.A., 2003, Optimal Inflatable Space Towers with 3-100 km Height, JBIS, Vol. 56, pp. 87-97, 2003


I was just reviewing an article on Physicist Robert L. Forward's Space Fountain. This structure does not depend upon material strength to build tall structures but rather is a device which has as its characteristic that it can support a structure of any height! Its function is described in the articles below, essentially however it uses superconducting magnets to keep small conductive particles in constant motion to support the structure via a transfer of momentum, see below.  This should be a much cheaper mechanism to large structures or even a tether.

Please, see the following links for further information:

Space Fountain:

http://en.wikipedia.org/wiki/Space_fountain
http://orbitalvector.com/Orbital%20Travel/Space%20Fountains Space%20Fountains.htm
http://www.strangehorizons.com/2003/20030714/orbital_railroads.shtml

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #84 on: 09/04/2012 12:01 PM »
What's your cost estimate?

It is still to soon to say. I'm still defining the system. I don't want a ball park figure. I can pull something out of the air and make it sound competitive but that would be worthless. I want to do a detailed cost analysis and then compare it with the new commercial systems such as SpaceX. The SpaceX system has real cost associated with it. SpaceX and other companies that are competing for the commercial launch business are my real competitors. I first need to convince myself that the Space Track Launch System is cost competitive before I proceed. It may not be.

Offline FinalFrontier

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Re: Space Track Launch System
« Reply #85 on: 09/04/2012 12:22 PM »
Really doubt this would ever work. Seen this sort of thing before.
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Offline JohnFornaro

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Re: Space Track Launch System
« Reply #86 on: 09/04/2012 07:02 PM »
Well I think you're off your rocker .... but I hope the permitting goes smoothly ...
  Probably, but since no one has convinced me that my physics is wrong, I'll continue on.

Unfortunately, you left out part of DCPorter's comment, which I bolded.  There may not be anything wrong with your physics equation.  You can't build it without a permit.  Or a cost estimate.  Or the engineering particulars of how such a tall tower would be constructed.

But hey.  What do I know?
Sometimes I just flat out don't get it.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #87 on: 09/06/2012 12:17 PM »
Really doubt this would ever work. Seen this sort of thing before.
Where? Please post your references. We can debate this further if I know what you are referring to.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #88 on: 03/17/2013 10:12 PM »
     To build a 25 km support tower for the proof of concept system, first I have to build a 1.5 km multi-beam construction tower. I propose using four relatively thick inflated beams evenly spaced around the circumference of the first level, one construction beam (CB) per cluster. The beams will be thicker because of the stress placed on them by climbers. The critical buckling load limits the height of a single inflated beam to about 500 m. The beam is divided into five 100 m air cells. Each cell has an independent air supply. The beam is inflated 100 m at a time. The climber climbs the first 100 m and the beam is stabilized with guy wires and ribbons attached to the climber (atch #1). The second 100 m is inflated, the climber climbs that 100 m, and stabilizes the beam (atch #2). The process is repeated until all five 100 m air cells are inflated and the beam is stabilized. Construction begins on all four clusters at the same time.

     Once stabilized, a beam inspection, maintenance, and equipment repair, robot (BIMERR) ascend the ribbon attached to the climber. The BIMERR carries a monorail section and installs it on top of the 500 m CB. The BIMERR returns to ground level. Two BIMERRs carry a rail car to the top and place it on the monorail section. Ribbons are also attached to the rail car. Two BIMERRs climb the ribbons attached to the rail car guiding the inflation of another CB with a monorail section attached to the top. Once inflated, the monorail sections are connected. The rail car moves over to provide support for the BIMERRs to inflate the next support CB with a monorail section. The process is repeated until all 50 beams on the cluster are inflated. When the four clusters are connected, the CBs become part of a mult-beam structure and the critical buckling load increases by six orders of magnitude.

     The second 500 m layer and the third 500 m layer are completed using the same procedure resulting in a 1.5 km mult-beam construction tower with a critical buckling load of ten to the ninth newtons. BIMERRs bring up sections of the first level interface ring and assemble them over the construction tower. BIMERRs guide the inflation of 1.5 km support beams and attach them to the interface ring (atch #3). The CBs are deflated and moved to ground level. Support beams are inflated to fill the vacancy left by the CBs and the first 1.5 km level of the 25 km support tower for the proof of concept system is complete (atch #4).

     The CBs are moved to the next level to construct the second level of the support tower. The procedure is repeated until all 16 levels of the support tower are completed. BIMERRs bring up sections of the elevator support structure, assemble the structure, and drop elevator ribbons to ground level. Construction crews travel to the top of the tower and assemble the rest of the system and proof of concept begins.

     A more detailed description of the proposed construction technique can be found in the concept papers section of www.fisherspacesystems.com under the title Proof of Concept System - Addendum A - Tower Construction.
« Last Edit: 03/18/2013 10:24 PM by Jerry Fisher »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #89 on: 06/10/2013 12:42 PM »
The Critical buckling load is the main design driver for the 1.5 km support beams of the Space Track Launch System and is the main reason for using 500 m inflated beams for the construction tower. I was using the elastic modulus of Kevlar to design both the support tower and the construction tower. According to the results in Task #1, increasing pressure has a minimal effect on the elastic modulus of the Kevlar/Mylar inflated beam. The elastic modulus was an order of magnitude less than the material modulus of Kevlar. In the Euler equation, the critical buckling load is directly proportional to the material modulus.

In the 1960s, NASA was interested in inflated beams for satellites, space stations, and reentry vehicles. W.B. Fichter, NASA Langley Research Center wrote a NASA technical note titled "A Theory for Inflated Thin-Wall Cylindrical Beams" in which he derived a theory which indicates that the radius of the beam has a more significant impact on the elastic modulus of the Kevlar/Mylar beam than pressure. The radius of the tested beam was 6 cm. The radius of the support tower is 1 m. I'll be exploring this variable in the next research task.

Go to my updated web site at fisherspacesystems.com to review my end of task report (ETR20130510) in more detail.

Offline gbaikie

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Re: Space Track Launch System
« Reply #90 on: 06/11/2013 02:45 AM »
The Critical buckling load is the main design driver for the 1.5 km support beams of the Space Track Launch System and is the main reason for using 500 m inflated beams for the construction tower. I was using the elastic modulus of Kevlar to design both the support tower and the construction tower. According to the results in Task #1, increasing pressure has a minimal effect on the elastic modulus of the Kevlar/Mylar inflated beam. The elastic modulus was an order of magnitude less than the material modulus of Kevlar. In the Euler equation, the critical buckling load is directly proportional to the material modulus.

In the 1960s, NASA was interested in inflated beams for satellites, space stations, and reentry vehicles. W.B. Fichter, NASA Langley Research Center wrote a NASA technical note titled "A Theory for Inflated Thin-Wall Cylindrical Beams" in which he derived a theory which indicates that the radius of the beam has a more significant impact on the elastic modulus of the Kevlar/Mylar beam than pressure. The radius of the tested beam was 6 cm. The radius of the support tower is 1 m. I'll be exploring this variable in the next research task.

I can't say I grasp the details of this concept.

Generally it seems you want to put a rocket at higher elevation.

Also seems like you want to use air pressure with large structures, and for large structures, and 30 psi a quite a significant pressure.

A way I would begin to look at it, is that if dealing with such large structures would be to make them float.

A problem with lighter than vehicle is they must be big- but also if something needs to be bigger it's easier design it to float.

Or if going to go to the trouble to encase entire city in glass, it not much a of leap to go to the floating the entire city- Buckminster Fuller stuff:
http://en.wikipedia.org/wiki/Floating_city_%28science_fiction%29
But encasing a city in dome, isn't cheap or easy, but I mean if going to such extreme it's not much added to it.

So just building an entire city is hard, putting dome on it is hard to do, but in comparison to that scale of difficulty, making a floating city not much harder.
Particularly, if lots of people actually really wanted to live in a floating city [for whatever reasons].

Now, as I said elsewhere, making any structure 5 km high could be desirable as restaurant.
Could make more money selling food than launching rockets. And restaurant business is tough business to be profitable. Though having safe rocket launches and restaurant might be winning combination.

So a structure +5 km high and say less than billion dollars seems like it
could be marketed for various purpose. A 1000 tons is big restaurant- if this mass is mostly customers and kitchen.

Location of such structure is important for restaurant or for launching rockets. So where a 25 km or 150 km tall structure be placed?
For instance, the equator is generally good for rockets to get to GEO.

More specifically I would like to get more information about buckling and thin-walled structures. And without reading the book [which I would like to get] it's not surprising that pressure doesn't help much in terms of buckling and larger diameter [and pressure] is more significant.
Though there seems there some limit in terms very large diameters. By which I mean a very large diameter becomes less curved more similar to a flat structure.
Though I am more interested in metal rather than Mylar.
So thing I am interested in is say 20 meter diameter 1/2 steel thick wall
and 20 meter tall- that would require massive amount of load [far more than 1000 tons] to make it buckle, though much less, if 100 meter tall. Pressure would help a little bit- but I assume not much.
And making the large cylinder from smaller cylinders- one is simply adding more material, but also increasing the curved surfaces- making the large cylinder less like a flat surface.


Online ChrisWilson68

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Re: Space Track Launch System
« Reply #91 on: 06/14/2013 11:46 AM »
What's your cost estimate?
It is still to soon to say. I'm still defining the system. I don't want a ball park figure. I can pull something out of the air and make it sound competitive but that would be worthless. I want to do a detailed cost analysis and then compare it with the new commercial systems such as SpaceX. The SpaceX system has real cost associated with it. SpaceX and other companies that are competing for the commercial launch business are my real competitors. I first need to convince myself that the Space Track Launch System is cost competitive before I proceed. It may not be.

It's never too soon to make a cost estimate.

You can make a rough order-of-magnitude estimate of costs that is neither a detailed cost analysis nor something out of the air.  Then you can continue to refine the cost estimate as you go.

My guess would be you'll find the cost with current technology is at least a thousand times the cost of putting the same payload into orbit with existing expendable launch vehicles, even assuming there's a market for the several tons per day you're talking about.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #92 on: 06/16/2013 12:09 PM »
I can't say I grasp the details of this concept.

Generally it seems you want to put a rocket at higher elevation.

Also seems like you want to use air pressure with large structures, and for large structures, and 30 psi a quite a significant pressure.

A way I would begin to look at it, is that if dealing with such large structures would be to make them float.

   Launching a rocket at a higher elevation contributes about 3-4% of the total mechanical energy for orbit. It is true there is an increase in rocket performance due to reduced air pressure but, in my opinon, the advantages do not justify the expense. Therefore, floating a rocket to high altitude is not the solution.

   To justify the expense, the second stage launching from the Space Track Launch System (STLS) has a significant kinetic energy and, along with the potential energy, contributes about 12-13% of the total orbital mechanical energy. The rest of the orbital energy comes from the chemical energy stored in the launch vehicle. Also, the STLS can launch up to six launch vehicles a day. Of course, the present market will not support six launches a day but, the day is fast approaching when it will (e.g. Deep Space Industries, Planetary Resource, NSS Roadmap, etc.).

   Finally, the working pressure for the inflated beams is about 130 psig and, as stated, is quite a significant pressure. I've had my test beams over 70 psig and it was a little nerve racking. Getting the beams up to 130 psig and holding that pressure for up to a year or more is one of many challenges.
« Last Edit: 07/16/2013 12:05 PM by Jerry Fisher »

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #93 on: 06/23/2013 02:31 PM »
It's never too soon to make a cost estimate.

You can make a rough order-of-magnitude estimate of costs that is neither a detailed cost analysis nor something out of the air.  Then you can continue to refine the cost estimate as you go.

My guess would be you'll find the cost with current technology is at least a thousand times the cost of putting the same payload into orbit with existing expendable launch vehicles, even assuming there's a market for the several tons per day you're talking about.

   Nah! It is still way to soon to make a cost estimate besides, what's the big rush? I've just started my research and have at least 5-10 years of research ahead of me. There are many technical issues to be resolved any one of which could doom the Space Track Launch System (STLS).

   The recent results on the test beam show that the elastic modulus is an order of magnitude less than what I used in the design of the first generation STLS. Since the critical buckling load is directly proportional to the elastic modulus, the buckling load is 10 times less than the design value. Therefore, the elastic modulus of an inflated beam using Kevlar 49 is a big technical issue.

   Kevlar 49 is one of the cheapest readily available high strength fabrics I could find. Spectra 2000 (TM) is 10 times more costly and graphene is about 100 times more costly (and they are not yet readily available). This fact alone blows an order of magnitude cost estimate out of the water (or out of orbit). If the elastic modulus of the inflated beam does not increase with radius, the first generation tower using Kevlar 49 may not be possible. I'll have to reduce the length of the inflated beams (which means more beams) or go with more costly materials. My research is my hobby and hobby funds are limited.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #94 on: 07/01/2013 10:42 AM »
Or if going to go to the trouble to encase entire city in glass, it not much a of leap to go to the floating the entire city- Buckminster Fuller stuff:
http://en.wikipedia.org/wiki/Floating_city_%28science_fiction%29
But encasing a city in dome, isn't cheap or easy, but I mean if going to such extreme it's not much added to it.

So just building an entire city is hard, putting dome on it is hard to do, but in comparison to that scale of difficulty, making a floating city not much harder.
Particularly, if lots of people actually really wanted to live in a floating city [for whatever reasons].

   I am not sure what you are referring to. I have no plans to enclose an entire city in a glass dome. However, a floating city at 5N125W is an option. This lat/long is near the InterTropical Convergence Zone (ITCZ), has a very mild weather pattern, and is near enough to the equator to give an extra 0.4 % of the total orbital energy required.

   The inflated beams at the base of a second generation system have a load of about 200-400 psi and would sink approximately 200-300 m below the surface of the water. The radius at the base of the tower would be about 500-600 m (large enough for a small city) and the six sets of guy wires anchoring the torque buffer and support tower would fan out to a radius of about 100 km. It is possible that a water based tower could be constructed by inflating the beams below water making construction of the tower relatively easier. After looking into it some, building the Space Track Launch System in the pacific ocean on the equator compared to building the tower in the continental United States has a lot of advantages.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #95 on: 07/08/2013 01:50 PM »
Now, as I said elsewhere, making any structure 5 km high could be desirable as restaurant.
Could make more money selling food than launching rockets. And restaurant business is tough business to be profitable. Though having safe rocket launches and restaurant might be winning combination.

So a structure +5 km high and say less than billion dollars seems like it
could be marketed for various purpose. A 1000 tons is big restaurant- if this mass is mostly customers and kitchen.

Location of such structure is important for restaurant or for launching rockets. So where a 25 km or 150 km tall structure be placed?
For instance, the equator is generally good for rockets to get to GEO.

   I'll let someone else handle a 5 km high restaurant. I plan on having a research station at the top of my tower. The station will be staffed intermitently by 5-10 researchers. All of the researchers will be fully qualified on emergency procedures to handle any anticipated emergencies. I'll have my hands full just getting this through the regulatory process. I can't imagine the emergency procedures and regulations required for 150-200 customers and staff (no matter what the altitude).

   As is currently planned, launching spacecraft off the Space Track Launch System (STLS) involves a temporary situation where the spacecraft is taken to the top and thrown off once every 6-8 hours. The first generation system will launch a single place orbital spacecraft. The pilot may require several technicians to assist with the launch. The second generation system will have a pilot and 6-8 passengers on board the orbitial spacecraft with several technicians to assist in the launch and the boarding of the passengers. Again, all STLS employees will be fully qualified to handle anticipated emergencies. The passengers will have classroom instructions before the flight on their roles in the event of an emergency.

Offline Andrew_W

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Re: Space Track Launch System
« Reply #96 on: 10/30/2013 07:56 AM »
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 #97 on: 05/01/2014 05:14 PM »
   The guy wires for extremely tall towers is one of several obstacles for the Space Track Launch System. Guy wires of constant cross section are not practical. The solution is to taper the guy wire and construct it from the top down during each phase of construction. Theoretically, a tapered Kevlar cable 50 cm wide could be used for the 25 km proof of concept system. Going to a tapered Kevlar cable would increase the dynamic load on the proof of concept tower by a factor of five. As such, the tower design needs to be updated. Further details can be found in the attachment below.

Offline Jerry Fisher

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Re: Space Track Launch System
« Reply #98 on: 05/04/2016 09:37 PM »
  I'd like to introduce the Phoenix suborbital launch vehicle (SLV). The concept design for the Phoenix SLV is shown in the figure below.

  The Phoenix SLV is a manned second stage launch vehicle designed to launch from the Space Track Launch System proof of concept tower. The proof of concept system will demonstrate the launch of a second stage suborbital launch vehicle with separation from an overcarraige on a rotating ribbon. After separation from the overcarraige, the Phoenix SLV will accelerate and coast to an altitude greater than 100 km, deploy and reenter using a paraglider, and land on a conventional runway.

  The Phoenix SLV can also be designed to launch from any 20-25 km free standing tower such as the Space Elevator tower recently patented by Thoth Technology Inc. (Quine, Brendan, M., Space Elevator, Patent No. US 9,085.897 B2, Thoth Technology Inc., Jul 21, 2015).

  Two advances make the Phoenix possible. First, a standard design pressure fed hydrogen peroxide (HTP)/E85 rocket engine using mixed metal oxides (MMO) as the catalyst. With the MMO, 98% HTP can be used for the oxidizer. HTP is room temperature storable and high density. As such, the Phoenix can be made to be low cost, simple, and reusable.

  The second advance is the flexible thermal protection system (FTPS) developed by NASA (Calomino, A.M., Dec, J.A., Del Corso, J.A., Sullivan, R.M., Baker, E.H., Bonacuse, P.J., Flexible Thermal Protection System Design and Margin Policy, 9th International Planetary Probe Workshop, Toulouse, France, June 2012). The 1st generation FTPS can withstand heat fluxes of 25 W/cm2 and the pyrogel insulator layer can absorb energies up to 5000 J/cm2. For the Phoenix SLV, an FTPS type material can be used for an inflatable keel, two inflatable booms, and the canopy for a re-entry paraglider.

  For more information, download the Phoenix SLV pdf below.


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