Author Topic: Space Track Launch System  (Read 37636 times)

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 »

Offline 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.

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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

Offline Jim

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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.

Offline JohnFornaro

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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.

Offline 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 »

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