Project FOOF - Declassified!

If polywell fusion is developed, in what ways will the world change for better or worse? Discuss.

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Aero
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Postby Aero » Sun Jul 11, 2010 10:39 am

Betruger wrote:This is the website I'd found some details from.
http://www.freepatentsonline.com/
You might get just enough details for a reasonable enough estimate of the specifications of those unannounced jumbo modules.

I found one patent with some detail, Filing Date: 09/27/2007. Some interesting stuff - for example, this paragraph on self sustaining negative potential well -
Another physics feature of importance in system operation is that the fusion products will, in general, not deposit their energy in the plasma region (as in the case in “conventional” concepts for fusion), but will escape from this region to the structures and surfaces bounding the polyhedral magnetic/plasma system. In this escape, these particles will leave as positively charged ions, thus increasing the net negative potential of the plasma region. Each fusion event will cause an increase in the well depth which is confining the reacting ions, hence will cause an increase in the particle density and resulting inter-particle reaction rate which will, in turn, cause a further increase in the negative potential, the well depth, etc., etc. The onset of fusion reactions in a negative potential well of the type contemplated herein will thus initiate a self-generating process to increase the well depth and thus to increase the fusion rate. Under certain special conditions (of total recirculating ion current) it is possible, but not certain, that-once started-a reacting assemblage of this type could become self-sustaining without any further excess external electron injection, beyond that needed for balance with the ion injection rate itself. In any case, this self-generating-well effect might allow the reduction of electron injection for well sustenance, and thus could result in a reduction in the externally-supplied power required to drive the electron injection system.

http://www.freepatentsonline.com/y2008/0187086.html
Aero

BenTC
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Postby BenTC » Sun Jul 11, 2010 2:34 pm


What is meant by the term "dielectric field" as in...
"two oppositely-charged particles are tied together by their dielectric field."

Is it different somehow from "electric field".
In theory there is no difference between theory and practice, but in practice there is.

zapkitty
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Postby zapkitty » Mon Jul 12, 2010 3:00 am

WizWom wrote:Even in LEO, the vacuum is much lower than you can get on Earth.
Your polywell in space for space only work does not need a vacuum chamber. All you need is the core, and your energy grid. And a simple reflector system on one hemisphere will allow it to produce thrust - and, incidentally, serves as primary shielding.

Owing to this, you need only be at the diameter of the core - 1 to 1.5 meters, and then you can use an extending shield/thrust plate.

Its likely you could fit an interplanetary craft with a polywell power source into a space shuttle easily. The Ares V should also have no trouble. Make it structurally capable of lunar landing, and a couple tons of equipment allows fueling from lunar ice.

And then you can go anywhere you please, as power and rocket mass are both effectively unlimited.


You overlook the fact that in LEO the reactor will need 360 degrees of debris shielding if you want to keep it functional.

As for the rest... that's blue-sky projects...

... btw a BA-330 modified into a polywell power module could fly on a Spacex Falcon 9 years sooner than on the Ares V... assuming that the Ares V can get itself uncanceled :)

Now there's nothing wrong with blue-sky projects at all but the point of FOOF is to get the much-needed spaceborne fusion experience that will prove the blue-sky projects feasible and make them much easier to implement.

FOOF does this by filling a need on orbit for abundant power that's immensely cheaper than solar, vastly easier to manage than solar, and much more easily protected against debris damage than solar.

Thus my question: can a polywell operate at net power in the 100-150 kW output range? That would make it plug'n'play with current spacecraft power systems and reduce its heat output to something current spacecraft cooling systems can handle.

And thus also my followup question: can such a low-level reactor be dialed up to higher power levels as more advanced cooling systems are developed and brought online?

... btw... Bigelow has updated their site and the new information indicates that the interior diameter of the BA-330 is 6.7 meters... this would make fitting a polywell installation and associated gear into a BA-330 much easier ...

zapkitty
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Postby zapkitty » Mon Jul 12, 2010 3:12 am

GIThruster wrote:Kitty, I love the idea here in this thread, but don't you think that before we see real investment on orbit, we need to see a new transport system that is safe, quick, convenient and economical? Once we have that, what goes to orbit seems almost trivial by comparison.


Sure... but one of the points of FOOF is demonstrating that fusion is viable now... so waiting 7-10 years for a fusion-powered launch system to be developed would seem to be contraindicated.

Of course 7-10 years is just my estimate on the subject... but I'd be very surprised if even the mighty SpaceX could field an entirely new type and class of launcher in less time than that.

zapkitty
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Postby zapkitty » Fri Jul 16, 2010 3:37 pm

Relevant news for polywell deployment in space:

Senate Authorization Committee puts forth the Congressional counter to President Obama's FY '11 budget.

http://spaceflightnow.com/news/n1007/15senate/

Essentially skips the Ares I boondoggle, restores Orion to its original deep-space parameters and goes for an SDHLV ASAP... 2016 or earlier.

The key members of the Appropriations Committee that actually allocates the funds are said to approve of the plan.

And, apparently seeing the writing on the wall, the Administration has signaled preliminary agreement.

And the SDHLV language puts JSC's sidemount out of the picture so it looks like an inline solution... i.e. Direct has won the day... although it is almost certain that the HLV will not be called Jupiter :)

And any inline SDHLV has the capability to loft a pre-assembled polywell module to LEO.

Assuming, that is, that NASA's near-death experience causes the MSFC hierarchy to pull their collective heads out of their asses and actually get the job done and done right this time...

Side note: not so good for commercial space, but Obama was never going to fund that to the proposed levels regardless of his promises.

jsbiff
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Postby jsbiff » Tue Jul 27, 2010 9:04 pm

Pardon a possibly stupid question on my part, but. . .

It seems to me that, wouldn't one of the first things you would want to do is to put a polywell reactor on some sort of conventional rocket, and test what effects, if any, high-G acceleration has on the reaction?

In a (relatively) stationary (of course, even something in a 'stationary' terrestrial installment moves with the rotation of the earth about it's axis, and its orbit around the Sun, but those are very small-G accelerations), it seems to me, you have a nice 'balance of forces', but in a high-G situation, you have a bias based on the direction of acceleration - forces not normally present in the terrestrial scenario.

I suppose that your magnetic and electrical fields are so powerful that the acceleration force *should* be negligible, compared to them, but is it possible they'd be *just* strong enough to upset the reaction at all? Or, perhaps acceleration is fine up to a limit, at which point the forces are strong enough to disrupt? Seems you would want to test out and know what any such limit is before designing a ship around a polywell? Or, even if you don't find the limit, maybe the testing confirms that up to some proposed design limit (max acceleration 5G or something) it's not a problem?

KitemanSA
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Postby KitemanSA » Wed Jul 28, 2010 12:22 am

jsbiff wrote:Pardon a possibly stupid question on my part, but. . .

It seems to me that, wouldn't one of the first things you would want to do is to put a polywell reactor on some sort of conventional rocket, and test what effects, if any, high-G acceleration has on the reaction?
Forget a rocket. Try a centrifuge. Want 5 G, set the dial. Want 10G, dial it up.

WizWom
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Postby WizWom » Wed Jul 28, 2010 2:27 pm

jsbiff wrote: test what effects, if any, high-G acceleration has on the reaction?


The particles in a polywell are experiencing on the order of tens of thousands of meters per second acceleration; an addition of a few tens of meters is trivial.
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D Tibbets
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Postby D Tibbets » Wed Jul 28, 2010 5:05 pm

I would guesstimate that the acceleration forces are several orders of magnitude above this. If ions are accelerated to several hundred thousands of meters per second in microsecond time frames. the acceleration would be in the range of billions of G's. The shaking effects of takeoff on the structure would probably be a much greater concern. Once in orbit there would not be any acceleration experienced by the reactor except when the space craft/ station is producing thrust itself to adjust the orbit/ attitude or to go someplace else. This would probably result in accelerations well below one G.

Dan Tibbets
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IntLibber
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Postby IntLibber » Sat Apr 02, 2011 6:01 am

GIThruster wrote:Kitty, I love the idea here in this thread, but don't you think that before we see real investment on orbit, we need to see a new transport system that is safe, quick, convenient and economical? Once we have that, what goes to orbit seems almost trivial by comparison.


SpaceX's Falcon rockets have a plan for development that leads from the Falcon 9 to a Falcon X, and a Falcon XX which is on a par with the old Nova launcher designs. Falcon XX should certainly be able to launch a full 100 MW pB11 polywell reactor, housing, and a shadow shield, both in terms of mass and diameter.

Giorgio
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Postby Giorgio » Sat Apr 02, 2011 3:20 pm

I love SpaceX guys, but if a 100 MW pB11 Polywell reactor will be developed we will probably not need anymore SpaceX rockets.

93143
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Postby 93143 » Sat Apr 02, 2011 8:12 pm

It'll be quite a while before a Polywell small and light enough to help with launch is available. 100 MW won't do it. (Remember, each SSME puts out ~5 GW in a vacuum, at an Isp of just 452.5 s, and thrust and Isp are roughly inversely proportional at constant power.)

I worked up an all-rocket Polywell-powered SSTO example here, with fairly optimistic assumptions; the required power-to-mass ratio came out really high:

http://www.talk-polywell.org/bb/viewtop ... 8467#48467

Airbreathing is better, but according to my calculations it still requires a large, as-compact-as-possible gigawatt-range reactor to maximize the power-to-weight ratio (especially if the gamma-producing branch of the p-¹¹B reaction turns out to be real, which it probably will; a foot-thick wall of lead is not light even as a shadow shield).

It also requires a fantastically advanced airbreathing engine.

A 100 MW demo plant is not exactly a flight-weight reactor, and even if it were, no engine exists for it to power. It'll be a while before SpaceX sees any competition from Polywell.

Skylon, on the other hand...

zapkitty
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Postby zapkitty » Sun Apr 03, 2011 2:01 am

The point being that if a spaceworthy fusion power plant can be proven...

... even if it cannot launch itself into orbit...

... then the solar system is open for human exploration.

Assembly on orbit is an old concept and one that we're all too experienced with because of ISS and launcher limitations.

Add inflatable hulls to the mix and humans could go where they like when they like.

A ship that goes to Mars in less than a month is no less a game changer just because an F9 hauled the polywell parts up to orbit.

Giorgio
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Postby Giorgio » Sun Apr 03, 2011 1:12 pm

@93143
Of course you can't hope to get to orbit with a 100 MW demo reactor.
My point was that once the technology is demonstrated it will probably not take much time to render it feasible for rocket use.

93143
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Postby 93143 » Sun Apr 03, 2011 5:44 pm

I think the gap is actually pretty large. You're talking about well over an order of magnitude in reactor power, requiring (among other things) considerable advances in superconducting magnet technology. Vacuum pumping requirements and cooling requirements are higher in proportion to the power output, and beam spreading in the direct converters looks to become problematic at these power levels. It also isn't enough to just make a 5 GW core; you have to do it small enough that the radiation shielding isn't a deal-killer.

And then you have to design the engines to use it. All-rocket would probably be easier, but then you have to have a reactor on the order of 100 kW/kg. Airbreathing has a lot more margin for reactor weight, but the engines need to be ridiculously sophisticated. Just look at how slowly scramjet research has been progressing.

Finally, all this has to come in at a low enough price to actually undercut whatever is available in the chemical launcher business at the time. This is by no means as easy as a lot of people seem to think.

Putting together a launch vehicle based on existing rocket technology takes on the order of 5 years. Reaction Engines Limited is due to demonstrate their engine technology this summer, and they don't expect to fly an actual Skylon until 2018. I don't expect a Polywell-powered launch vehicle to steal REL's thunder, never mind SpaceX's... it would take a Manhattan-style project, if it's possible at all, and I just don't see that happening...

...

In space, on the other hand... have you heard of the NAUTILUS-X? You know, NASA's proposed modular exploration ship with the swappable propulsion section?


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