NewSpace 2010: Polywell and Vasimr

Point out news stories, on the net or in mainstream media, related to polywell fusion.

Moderators: tonybarry, MSimon

AcesHigh
Posts: 643
Joined: Wed Mar 25, 2009 3:59 am

Postby AcesHigh » Thu Aug 05, 2010 3:26 am

finally... I dont like the idea of having to share the galaxy with millions of other civilizations who probably already settled all good planets...

IntLibber
Posts: 747
Joined: Wed Sep 24, 2008 3:28 pm

Postby IntLibber » Thu Aug 05, 2010 3:53 am

AcesHigh wrote:@GIThruster:

sorry pal, I dont see any evidence that ETs have visited us in the past. You probably know that all allegations of paintings (medieval, ancient or pre-historic) showing aliens or craft are probably very well debunked. I guess you have other evidence besides paintings?

also, I will believe faster that the aliens are in fact humans from the far future (or not so far future, considering we already are close to mastering genetic engineering) than aliens... I mean... grays look just like human fetuses!! I seriously doubt we will find so easily aliens that look so much like us, considering we are the result of billions of years of evolution and some quite random chances...


This is an entirely separate issue from the topic at hand and should be its own thread. GI is entirely right about the RB47 incident, there is in the historical record data about the EM emissions that the RB47 detected emanating from the UFO they encountered. This makes it a real and not hallucinated phenomena.

I also agree that the Roswell incident, as well as a few others (that one in pennsylvania, which may or may not have merely been a failed test of a captured German agrav experiment) are sufficiently credibly documented of and by enough people that the odds of these incidents being fabricated is nil.

However, being an air force veteran who has entered area 51, I can say with certainty that the OSI intentionally promoted UFO reports around Area 51 as a means of discrediting anybody who saw any classified aircraft being tested there.

The idea of greys being future human time travellers: the warp/wormhole part of the Mach Effect math doesn't really distinguish between travel in space vs travel in time. These dimensions are interchangable, and assuming that some future generation is able to make that part of the math work technologically, they are going to have a very interesting problem of time-space navigation to deal with to avoid creating loops, parallel universes, and other paradox-created situations. It stands to reason that even with a functioning technology, there are going to be navigational failures from time to time. Those who do suffer from such failures will disappear from their own timelines and create new timelines in the past. They are still as much "alien" to the new timeline as beings from another star system.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Thu Aug 05, 2010 4:43 am

Well as I said, I don't have an opinion of who is flying the craft as I haven't seen evidence one way or another. Creatures from afar, be it time or space, seems incredible enough for me and I'm not willing to make a guess as to who they are.

My point is that the evidence for the craft themselves is truly overwhelming. Critics often say there's a lack of evidence but this is surely not the case. There are so many times that these craft have been sighted by hundreds of people at a time, and observed to turn right angles in the sky--descriptions that show a level of mastery over inertia that we have not got--that I am a hold out for that sort of technology.

Whether the craft are using M-E thrusters like what we've been talking about, or if they are using warp to fly time-like geodesics, or if they've passed through a wormhole and traveled through time, all three of these types of propulsion are enabled by Woodward's physics.

Why settle for less?
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

neutron starr
Posts: 14
Joined: Mon Jan 05, 2009 6:30 pm
Location: Brooklyn Polytechnic

Postby neutron starr » Sat Aug 07, 2010 7:49 pm

As to ET's that's another topic and doesn't belong here.

As to Space elevators well the tensile strength, construction and funding problems may or may not be solved but the one problem that proponents never talk about is orbital debris. So we build the tower. It has a ground speed of 0 mph. What happens to said expensive tower when it is intersected by a bolt from an early satellite launch or even worse a satellites, ether of witch having a ground speed of roughly >1000 mph. Now I see that the tower won't destroy things on the ground when this happens and it falls (it's too light) but it cost money to put the tower up money witch is all gone after such an event (this would make investors a bit unhappy).

I can think of three solutions 1 move the satellites/debris 2 move the tower 3 vaporize the satellites/debris. for 1 you would have to either take down all satellites in LEO or send special missions to give them all extra maneuvering thrusters (and i don't know how you would clean up the debris). for 2 how much extra stress (read cost) would the necessary thrusters on the tower add? for 3 your ether talking super powerful lasers (an engineering feet in itself) or anti missiles both of witch would add expense. not to mention that if a satellite is shot down it would be an international indecent.

as to M-E this looks great if it works. what are the best measured thrusts so far? if it works what makes anyone think it would be good for getting out of the earths gravity well? for it to be useful doing that it would need to have a thrust to weight of greater then 1 (this would have to include the weight of the power plant and the ship) a very tall order indeed. how much do the power sources and thrusters for these Milli-newton experiments weigh? how many orders of magnitude better thrust for current weights would be required to even approach greater then 1 thrust to weight? if this can't be achieved it's still useful but only for inter-planetary (and hopefully interstellar) travel. still a worthy goal but i think maybe a long time before they will be useful to get to LEO from the ground.

as to what i think would be a good short term solution (before polywell powered craft take over) for getting to LEO is, (and LEO is really 90% of what we want because once we're there we can use ion thrusters to go higher) I favor the gun type launchers. the best of those is a ram accelerator because it uses only cheap building materials and mature technologies (large diameter pipe automotive fuel injectors and exhaust valves and a big ordinary chemical gun to get the projectile up to mach 4 or 5 before it enters the accelerator). it probably wouldn't work for passengers (to much acceleration for any reasonable barrel length) but they could use rockets while the cannon brings up all the equipment. rail guns are less desirable because the rails wear fast an the high energy ones are new and experimental. mass drivers are good but a nice one would be long, about 22 miles for 1g acceleration about 7 or 8 miles for a 3g acceleration (why would anyone who can't take 3g's be going to space?). chemical guns don't work because can't get enough speed (it's been tried).

Really the best approach is try everything and only drop the dead wood when a solution is found and proven.
The measure of (mental) health is flexibility (not comparison to some ‘norm’), the freedom to learn from experience…The essence of illness is the freezing of behavior into unalterable and insatiable patterns.
Lawrence Kubie

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Sat Aug 07, 2010 8:29 pm

neutron starr wrote: as to M-E this looks great if it works. what are the best measured thrusts so far? if it works what makes anyone think it would be good for getting out of the earths gravity well?


In thrusters like the MLT and UFG, thrust efficiency scales with the cube of frequency. So for the case of the UFG, the maximum ionic response of the materials used (or its "phase angle") is in the low Ghz range. UFG's can run up to about that level before we have materials science limitations and need a new kind of thruster, say gaseous core for instance, (or find a new and better material.)

That means the thrust efficiency (and associated thrust) can be improved by about 100,000^3. Even with the micro-newton thrusts from a couple hundred watts seen to date, it's obvious this can be used for human spaceflight if it works at all.

There are other disclaimers, qualifications and details. For instance, the "wormhole contribution" in the thrusters is relatively insignificant below the dm=m condition or "wormhole barrier." Once you traverse the wormhole barrier and are creating delta mass greater than mass, you have negative mass with its consequent negative inertia. This is the stuff we need to build warp drives and traversable wormholes. It also adds to the thrust efficiency and the further you go, the larger one expects that wormhole contribution to be.

Of course, you asked "if it works what makes anyone think it would be good for getting out of the earths gravity well?" Well, "if it works" is a big IF. We don't really know just how efficient these thrusters can be made until we make them. I can tell you, there are certainly designs in mind that given the proper resources, we could push the limits of thruster efficiency quite quickly. A few hours on a laser sintering machine and a small team of EE's to build the proper power system, and it's possible we could have these very high magnitude, very high efficiency, thrusts happening in short order.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

KitemanSA
Posts: 6095
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Postby KitemanSA » Sun Aug 08, 2010 11:28 am

GIThruster wrote:
neutron starr wrote: as to M-E this looks great if it works. what are the best measured thrusts so far? if it works what makes anyone think it would be good for getting out of the earths gravity well?


In thrusters like the MLT and UFG, ...
...
...
... and it's possible we could have these very high magnitude, very high efficiency, thrusts happening in short order.
And even if we can't, putting this on a hypersonic Sky Hook is one way to magnify their effect. A HSH's main failing is the need to reboost after each momentum transfer. The system I've seen to date requires 14 days to accomplish this part of the cycle; a very limiting situation. The system is designed with a low thrust/weight electro-dynamic tether built in. It suggests that an auxiliary thruster (with fuel used) would improve the cycle time, but expend some of the expensive mass lifted. If the M-E can be as thrust efficient as an EDT but with a higher thrust density, it would be a good match.

neutron starr
Posts: 14
Joined: Mon Jan 05, 2009 6:30 pm
Location: Brooklyn Polytechnic

Postby neutron starr » Sun Aug 08, 2010 3:54 pm

MLT and UFG, thrust efficiency scales with the cube of frequency. So for the case of the UFG, the maximum ionic response of the materials used


You are casting pearls to swine. I'm ignorant of just about everything having to do with M-E thrusters. So the acronyms and tech talk are lost on me. All I know is they seem plausible considering that centrifugal force indicates an absolute frame of reference. Also I don't care about efficiency (you meant electricity to kinetic energy conversion efficiency right?) because I think Polywell will give us energy to burn. What I care about is Thrust to Weight or N/kg if this quantity is less than 1 for your thruster (let alone the craft) then ether there must be a different craft to carry stuff out of earth’s gravity well or every ship must have 2 sets of engines M-E's for interplanetary and some other for atmospheric maneuvers. This adds cost and diminishes the usefulness of M-E.

I only bring this up because the M-E proponents seem to have been saying earlier in this thread that M-E makes space elevators un-necessary or expensive overkill when if M-E has no confidence of getting over 1 for N/kg then M-E solves a totally different problem then the space elevator. I.e. we could use space elevators to get to LEO and then M-E to get to the moon and the other planets. So why are the M-E guys down on the space elevator when they need it (or some other solution for ground to LEO) to bring their thrusters up high enough to do any good?
The measure of (mental) health is flexibility (not comparison to some ‘norm’), the freedom to learn from experience…The essence of illness is the freezing of behavior into unalterable and insatiable patterns.

Lawrence Kubie

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Sun Aug 08, 2010 4:12 pm

neutron starr wrote:So why are the M-E guys down on the space elevator when they need it (or some other solution for ground to LEO) to bring their thrusters up high enough to do any good?


First of all, it's not that "the M-E guys" are down on the elevator. I'm sharing my own personal opinion when I say that these macro-engineering projects that require hundreds of billions of dollars are never going to be built. There are other "M-E guys" posting in this forum who might well disagree with me.

As to the distinction between thrust efficiency and thrust to weight ratio, there are several issues here.

First of all, a 1N/W thruster is not only not out of the question, but experiments to date imply that it's quite doable. All by itself, this enables human spaceflight direct out of our gravity well. Thrust efficiency implies a degree of thrust/weight, because larger, heavier thrusters will be requiring more electrical power to run them.

Second, while thrust efficiency is a measure of thrust to electrical power in, this could easily mislead you to believe that the thruster is a transducer that converts electrical to kinetic energy. This is not true. M-E thrusters are actually transistors, that control the flow of gravinertial energy. This is important to keep in mind because when we look at higher efficiencies, we'll be tempted to think we have a violation of conservation, should we mistake a transistor for a transducer.

Finally to answer your question about thrust to weight--you are correct to identify this as the single most important issue with regards human spaceflight direct off the planet. If I could assure you that this is a non issue, I would but we don't actually KNOW this is solved until it is solved. Just saying again, the efficiency issue implies that we will have thrusters capable of much, much more thrust/weight than necessary for human spaceflight direct off the planet, but we don't know this is so until it is so.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

ltgbrown
Posts: 163
Joined: Mon Jun 22, 2009 11:15 am
Location: Albania

Postby ltgbrown » Sun Aug 08, 2010 11:05 pm

OK, I am no aeronautical engineer nor a physicist. I know that and so if you all point a fundamental mistake in my reasoning below, I will not be offended nor defensive, so please be gentle! :)

I do not think we need a greater than 1 to 1 thrust to weight ratio M-E thruster to get to orbit (and of course beyond to the planets and..). What we need is a thruster with enough thrust to get our space vehicle airborne and still capable of accelerating. The thrust only needs to be greater than the induced and parasitic drag up to some amount. This amount is some peak value (over the brainiacs to figure it out, assuming my gut understanding is correct) that is reached while the vehicle is climbing and accelarating. The parasitic drag is related to indicated speed (a combination of speed and denisty), velocity and a constant. For induced, it is associated with the lift produced, indicated speed (and therefore denisty also) and a constant. Lift remains constant (ok, we are burning PB11, so weight decreases ever so slightly, so lets ignore that for now :D ) while climbing out. So, as density decreases, velocity can increase. Why do airplanes today not fly out to LEO? Because thrust decreases with denisty also. That is not a problem for a vehicle not using air as part of its thrust, like a rocket or (drum roll) a M-E thruster. Perhaps lift will decrease with density to a point that there just isn't enough ump to get any higher and the wieght of the vehicle is carefully balanced between what lift there is and thrust. Even so, my gut tells me that there is some thrust to weight point less than one to one that could accelerate a vehicle to escape velocity. I suppose if I spent several hours (ok, days maybe weeks) I could figure out the math (I did know it in college, but that was two decades ago!), but I have a foreign language to learn instead.
Famous last words, "Hey, watch this!"

KitemanSA
Posts: 6095
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Postby KitemanSA » Mon Aug 09, 2010 12:07 am

GIThruster wrote: I'm sharing my own personal opinion when I say that these macro-engineering projects that require hundreds of billions of dollars are never going to be built.
You have not, however, then explained how existing hundred billion and even trillion dollar mega-engineering projects have gotten built in the past.
They do exist. By your appearent beliefs, they could not, but they did happen. Just not as a full blown system. They were built in bits and pieces that were themselves profitable (or at least beneficial). I suspect that is how the space elevator will eventually happen too.
A hypersonic skyhook will be launched and then improved, then improved again, etc. until it has a ground track velocity of zero. Viola, a space elevator. At each step of the way, each improvement it will pay for itself. Welcome to business, boys!

By the way, current materials should be acceptable for a HSH even how, but it may be a while before the GTV falls much below ~5km/s.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Mon Aug 09, 2010 12:30 am

ltgbrown wrote:I do not think we need a greater than 1 to 1 thrust to weight ratio M-E thruster to get to orbit (and of course beyond to the planets and..).


itg, in order to build a spacecraft that can lift off our planet, thrust to weight of the thruster, has to be significantly more than 1/1. For space travel that is safe, quick, convenient and economical, space thrusters need to develop much more thrust to weight ratio than 1/1. You need to lift the entire spacecraft from our gravity well, not just the thruster and power source itself.

Just IMHO, what we have with the M-E thrusters is capable of much more than 1/1 thrust to weight. Much, much more.

As I consider all the transport systems proposed over the last 40+ years, nothing holds out the promise that the M-E thrusters do--not any multi-billion dollar transport system that requires fantastic mass to be lifted.

ONLY M-E thrusters hold out the promise of a true "Golden Age" of space transportation.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Mon Aug 09, 2010 12:40 am

Removed from better sense.

Peeps! If you want to see human space flight, it needs to pay for itself. Anything less is exploration, not emancipation.

Please, stop with the thinking some select group ought to be spending OTHER PEOPLE'S MONEY for kicks.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

ltgbrown
Posts: 163
Joined: Mon Jun 22, 2009 11:15 am
Location: Albania

Postby ltgbrown » Mon Aug 09, 2010 2:16 am

You need to lift the entire spacecraft from our gravity well, not just the thruster and power source itself


Sorry, I was using my avaition definition of 1 to 1 thrust to weight, which is thrust equal to the entire weight of the aircraft (or spacecraft), as in able to accelerate in the vertical, not a very common capability in aircraft. So, yes, the entire weight of the spacecraft needs to be lifted out of our gravity well. Does that mean you are saying that this can only be done with a spacecraft that is capable of producing more thrust than the entire spacecraft weighs?

As for "For space travel that is safe, quick, convenient and economical, space thrusters need to develop much more thrust to weight ratio than 1/1." that depends on your definition of safe, quick, convenient and economical. A spacecraft with .5 to 1 thrust to weight would seem pretty quick, convenient, and economical to most right now. Well, at least it seems so to me.
Famous last words, "Hey, watch this!"

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Postby GIThruster » Mon Aug 09, 2010 2:34 am

ltgbrown wrote:A spacecraft with .5 to 1 thrust to weight would seem pretty quick, convenient, and economical to most right now. Well, at least it seems so to me.


Yeah well I get that, but just being sincere: if your propellantless thruster can't deliver better than 1:1 thrust/weight, it can't be used as the primary thruster source for leaving our planet.

We need more like 5:1 thrust to weight.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Antice
Posts: 21
Joined: Sat Jun 12, 2010 10:04 am

Postby Antice » Mon Aug 09, 2010 3:32 am

For a Horisontal takeoff and landing craft the Vehicle T/W need only be around 0.5. anything less will lead to a requirement for having some kind of launch assist on the runway. however. once you are getting to climb above 30km or so altutude the TW needs to have grown to about 1 trough propellant dropoff. so for a propellantless thruster the vehicle TW has to be grater than 1.


Return to “News”

Who is online

Users browsing this forum: No registered users and 7 guests