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#31
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Super-heavy lift reusable launcher
Ian Parker wrote:
:On 10 Aug, 11:50, Fred J. McCall wrote: : Ian Parker wrote: : : :On 9 Aug, 23:35, Fred J. McCall wrote: : : Ian Parker wrote: : : : : : : : :You are assuming that heavy lift is need for SSP. In fact what you : : :require is the phase locking of small (a few Kw) units. : : : : : : : That may be what YOU require, but is anyone proposing building one : : that way? : : : : Why do I doubt it? : : : : : :Its the onlt logical way to do it. Having large parabolic mirrors at : :GEO is totally impractical. : : : : Oh, is it? *Why is that? : : While you're at it, why do you need "large parabolic mirrors at GEO" : for SSP? : : -- : "Some people get lost in thought because it's such unfamiliar : *territory." : * * * * * * * * * * * * * * * * * * * --G. Behn : :There are 2 basic approaches to beaming energy. One is to have a large :fixed mirror. The other is a phase locked array. I am discussing phase :conjugation and it is very interesting. Instinct tells me that a large :fixed mirror cannot be the way forward. : True, but that is primarily because using visible light for beaming power is not "the way forward". How do you propose to solve the minor problem with that stuff called 'cloud cover'? All this was worked out long ago. There's no reason to change it now. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
#32
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Super-heavy lift reusable launcher
In terms of size, here's an interesting chart
http://www.projectrho.com/rocket/rocket3f2.html The engines I've talking about would have a bell diameter that would neatly cover the city bus and would be about as tall as the Millenium Falcon. They would attach to a structure about the size of the Eiffel Tower. The payload could easily loft three fully loaded Saturn Vs into an escape trajectory at the same time - not that you would actually do that. Stage layout and operation is very similar to this vehicle http://www.astronautix.com/lvs/rombus.htm but larger.. |
#33
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Super-heavy lift reusable launcher
On 10 Aug, 12:36, Fred J. McCall wrote:
Ian Parker wrote: :On 10 Aug, 11:50, Fred J. McCall wrote: : Ian Parker wrote: : : :On 9 Aug, 23:35, Fred J. McCall wrote: : : Ian Parker wrote: : : : : : : : :You are assuming that heavy lift is need for SSP. In fact what you : : :require is the phase locking of small (a few Kw) units. : : : : : : : That may be what YOU require, but is anyone proposing building one : : that way? : : : : Why do I doubt it? : : : : : :Its the onlt logical way to do it. Having large parabolic mirrors at : :GEO is totally impractical. : : : : Oh, is it? *Why is that? : : While you're at it, why do you need "large parabolic mirrors at GEO" : for SSP? : : -- : "Some people get lost in thought because it's such unfamiliar : *territory." : * * * * * * * * * * * * * * * * * * * --G. Behn : :There are 2 basic approaches to beaming energy. One is to have a large :fixed mirror. The other is a phase locked array. I am discussing phase :conjugation and it is very interesting. Instinct tells me that a large :fixed mirror cannot be the way forward. : True, but that is primarily because using visible light for beaming power is not "the way forward". *How do you propose to solve the minor problem with that stuff called 'cloud cover'? All this was worked out long ago. *There's no reason to change it now. -- "The reasonable man adapts himself to the world; the unreasonable *man persists in trying to adapt the world to himself. Therefore, *all progress depends on the unreasonable man." * * * * * * * * * * * * * * * * * * * --George Bernard Shaw Clould cover is a sighting problem. It all depends where you are beaming to. If you want to electrolyse water you simply site yourself where there is little clould cover. If again you want to power aircraft at 10,000m there is little clould. William Mook is championing light. I am not convinced of the advantages over microwaves myself although we should, I think, have an open mind. The same arument about phase coherence occurs with microwaves too. - Ian Parker |
#34
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Super-heavy lift reusable launcher
On 10 Aug, 12:26, wrote:
On Aug 10, 6:20*am, Ian Parker wrote: On 10 Aug, 10:25, wrote: Yes, but remember that receiver and transmitter have to exchange photons in order to remain locked - so,the power beam will lag the motion of the receiver by whatever the delay time is. * For GEO this is 1/4 second. *At 930 miles altitude, this is 1/100th second. That is true. Having posted I was going to add that rider. You indeed need to extrapolate 2d/c ahead. Thus a degree of computation is unavoidable. Best done photonically - with the photons themselves in a photonic medium - whether microwave or optical. Possibly, but I don't think this is intuitively obvious. What you seem to be doing here and further on is inventing an optical computer. People have attempted to design them. An optical computer can (in theory) solve problems involving Fourier Transforms faster than standard digital computers. Leading question. Can we reduce an extrapolation problem to a series of Fourier Transforms? Yes we can. We put old data in and the Fourier Transform provides an extrapolation. However I regard this as really getting beyond the scope of this discussion. We should not be diverting intio new computing paradymes. I read through the rest. The basic principle of an array in physical optics is that your light intensity is a product of two things. It is the envelope of a single element * The envelope provided by the array viewed as point sources. Thus your individual element is going to have a fair spread. Check on the physics of sparse arrays of elements. *You can focus within the Rayleigh criterion - but the efficiency with which you do it goes to hell in a sparse array rather quickly - even if you resolved all the other open issues. Simple conjugacy gives a sub optimal solution in the sparse case - or does it? A sparse array gives us subsidary maxima and minima. We want to minimise enery in these subsidery maxima. Actually I am beginning to feel that conjugacy is optimal. I will think some more about it. I feel that a paper could be written on the subject. What we need to show is that depatures from conjugacy give a worse solution. I am working on this one. You are indeed correct in saying that you need equipment for detecting the phase of the source. Which is achieved automatically by putting a phase conjugate mirror on the backside of a laser cavity, and a phase conjugate window on the front. *You can get 1 million to 1 trillion power gain in such a system This is best done by having a unit which consists of a camera with a Michaelson interferomer. If all you want to do is detect. *However the simplest thing to do is to have a powerful laser equipped with nonlinear mirrors and front window and illuminate it with a bandgap matched laser from far away. The output of the laser will then direct itself immediately along the pilot beam in the opposite direction. The only computation is done by the designer of the control circuit. Knowing the power laser's properties, we know how long it takes for power to build up at the reciever, so power level is easily controlled by controlling the duration of the pulse - then the rate of pulse determines overall power. I think you will find that bang bang control systems do NOT give optimal solutions. This is provable. A conjugacy mirror must send the same AMPLITUDE back, An individual subunit (consisting of a number of units) would have a resolution of 1km. Your efficiency with a sparse array would be very very low - furthermore - you have instant response with a nonlinear window - even if constructed from microwave elements using linear op amps - and the system is more reliable besides. For a microwave system yes. You can have one transmitter, one receiver. For an optical array you can't. This BTW is not a sparse array in normal sense of the term. All transmitters will form a non sparse array. - Ian Parker |
#35
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Super-heavy lift reusable launcher
wrote in message
... In terms of size, here's an interesting chart http://www.projectrho.com/rocket/rocket3f2.html The engines I've talking about would have a bell diameter that would neatly cover the city bus and would be about as tall as the Millenium Falcon. They would attach to a structure about the size of the Eiffel Tower. The payload could easily loft three fully loaded Saturn Vs into an escape trajectory at the same time - not that you would actually do that. Stage layout and operation is very similar to this vehicle http://www.astronautix.com/lvs/rombus.htm but larger.. ============================================ Well, well, well. There is another of those wonderfully future oriented things "we" discarded in the late '60's and in the '70's, so as to free up money for that war in Vietnam. The effect of choices then upon the present and future now, is plain to see. ...Will this list ever end? ?? Titeotwawki -- mha [sci.space.policy 2008 Aug 10] |
#36
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Super-heavy lift reusable launcher
"Alan Erskine" wrote in message
... "Pat Flannery" wrote in message news At least Sea Dragon got into that engine size category: http://www.astronautix.com/lvs/searagon.htm Again; imagining something and actually making it happen are two different things. =========================================== OK on the obviosity. What's the point? Titeotwawki -- mha [2008 Aug 10] |
#37
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Super-heavy lift reusable launcher
"Fred J. McCall" wrote in message
... Ian Parker wrote: : :You are assuming that heavy lift is need for SSP. In fact what you :require is the phase locking of small (a few Kw) units. : That may be what YOU require, but is anyone proposing building one that way? Why do I doubt it? -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson ======================================== Note on that quote. Francis Bacon said it better: "Truth will sooner out from error than from ignorance." Titeotwawki -- mha [sci.space.policy 2008 Aug 10] |
#38
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Super-heavy lift reusable launcher
On Aug 10, 3:23 am, Ian Parker wrote:
On 9 Aug, 23:35, Fred J. McCall wrote: Ian Parker wrote: : :You are assuming that heavy lift is need for SSP. In fact what you :require is the phase locking of small (a few Kw) units. : That may be what YOU require, but is anyone proposing building one that way? Why do I doubt it? -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson Its the onlt logical way to do it. Having large parabolic mirrors at GEO is totally impractical. But not as from a Selene/moon L1 tether dipole element that's holding its termination pod or array of laser cannons at 2r from Earth. This Earth-moon L1 tether dipole element is originated at roughly 58,000 km from the moon, whereas it's LSE-CM/ISS (sort of tethered Clarke Station, except much larger and considerably massive) is efficiently station-keeping and sunny 97+% of the time, not to mention the secondary/recoil worth of the Selene/moon IR. Since there's no limits as to the taper or given volume of this primary lunar elevator tether, there's no problems with artificially establishing this tether within existing material specs. http://en.wikipedia.org/wiki/Lunar_space_elevator "Unlike the earth space elevator, the materials for the lunar space elevators don’t require a lot of strength. The elevator can be made with materials available today. Carbon nanotubes aren’t required to build the structure." http://www.lpi.usra.edu/publications...aryland01b.pdf http://en.wikipedia.org/wiki/Lunar_space_elevator http://www.star-tech-inc.com/papers/als/lunar.pdf And there's lots of other independent research besides that of my LSE- CM/ISS, though all of which is officially ignored and banished by the mainstream cabal that's still in a full blown damage control of their DARPA need-to-know and nondisclosure policy. ~ Brad Guth Brad_Guth Brad.Guth BradGuth |
#39
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Super-heavy lift reusable launcher
"Martha Adams" wrote in message
news:lJCnk.660$7N1.338@trnddc06... "Alan Erskine" wrote in message Again; imagining something and actually making it happen are two different things. =========================================== OK on the obviosity. What's the point? Just like Mookie's 'dream'; it'll never happen. For the reasons I've already stated. |
#40
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Super-heavy lift reusable launcher
Ian Parker wrote:
:On 10 Aug, 12:36, Fred J. McCall wrote: : Ian Parker wrote: : : :On 10 Aug, 11:50, Fred J. McCall wrote: : : Ian Parker wrote: : : : : :On 9 Aug, 23:35, Fred J. McCall wrote: : : : Ian Parker wrote: : : : : : : : : : : :You are assuming that heavy lift is need for SSP. In fact what you : : : :require is the phase locking of small (a few Kw) units. : : : : : : : : : : That may be what YOU require, but is anyone proposing building one : : : that way? : : : : : : Why do I doubt it? : : : : : : : : :Its the onlt logical way to do it. Having large parabolic mirrors at : : :GEO is totally impractical. : : : : : : : Oh, is it? *Why is that? : : : : While you're at it, why do you need "large parabolic mirrors at GEO" : : for SSP? : : : : -- : : "Some people get lost in thought because it's such unfamiliar : : *territory." : : * * * * * * * * * * * * * * * * * * * --G. Behn : : : :There are 2 basic approaches to beaming energy. One is to have a large : :fixed mirror. The other is a phase locked array. I am discussing phase : :conjugation and it is very interesting. Instinct tells me that a large : :fixed mirror cannot be the way forward. : : : : True, but that is primarily because using visible light for beaming : power is not "the way forward". *How do you propose to solve the minor : problem with that stuff called 'cloud cover'? : : All this was worked out long ago. *There's no reason to change it now. : : :Clould cover is a sighting problem. : No. If you're using visible light frequencies, cloud cover is a TRANSMISSION problem. : :It all depends where you are :beaming to. If you want to electrolyse water you simply site yourself :where there is little clould cover. : Which is rather like saying that if you want to electrolyze water you simply site yourself where there is little or no water. : :If again you want to power :aircraft at 10,000m there is little clould. : You're not going to do that from orbit. : :William Mook is championing light. I am not convinced of the :advantages over microwaves myself although we should, I think, have an pen mind. : In general, if William Mook is championing something, it is probably a good thing to stay away from. Mr Mook has a years-long reputation for wanting undoable things done. : :The same arument about phase coherence occurs with :microwaves too. : Solutions are already known. Use big transmitters and big rectennae for receivers. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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