space propulsion

[dgwalker]

Hi

Has anyone developed an electro-mechanical or mechanical means to propel spacecraft in orbit or space generally? This would involve defying Newton’s law of physics. Has it been seriously attempted or part successfully been done? Do you believe only Newtonian action and reaction (rockets, Ion propulsion etc.) is the only way to space propulsion known today. This is a serious question and a reply would be most appreciated.

Regards Doug Walker username dgwalker

 

[drwayne]

To date, no technology has been demonstrated publically that operates on any sort of non-Newtonian
way. That doesn't mean there aren't some out there, kooks, geniuses and crooks working on, pretending
to work on, are just blowing hot air about such technologies.

Welcome to the forum Doug! This sort of question can lead to some pretty wild speculation, which may
move it from the Physics section to the Unexplained section. I'll PM you if I have to do that.

Wayne

 

[dgwalker]

Thanks Dwayne

New to this forum. Didn't realise that this topic could cause an unpredictable stir. I did go to a site once that had all sorts of gooks putting forward wierd unproven science. This was a straight forward question which you have given a straight forward answer to.

Regards Doug

 

[Mee_n_Mac]

By way of mentioning non-Newtonian methods I'll assume you want to leave out solar sails, which expel no reaction mass. To date there hasn't been a successful test though one is planned in 2010 I think. The physics is sound, if not the engineering at this time.

The only non-quack idea (along the lines I think you're trying to get at) that I've heard of was here.

http://www.technologyreview.com/blog/arxiv/24499/

It probably is a quack idea but it's sufficiently cloaked that I can't tell. We do know the Casimir effect/force is real and observable. As far as the concept mentioned in the article, ???? At least it's promoter isn't saying it's free energy.

 

[drwayne]

I know I think of solar sails as "Newtonian", having done some problems in that area, I have the
strong mental picture of photons transferring momentum in a physics 101 fashion.

But then again, I am weird.

 

[EarthlingX]

This is electromagnetic, i think, and i'm almost certain it doesn't have much to do with Newton ..
Quantum propulsion (forum)

I can probably dig out some more weird, bordering on The Unexplained stuff
like :
Anti-gravity

Not much news on this one lately .. :roll:

 

[drwayne]

Note that I used the term - demonstrated, there are some - interesting ideas out there...

 

[EarthlingX]

Note that I used the term - demonstrated, there are some - interesting ideas out there...

Which of those ideas have in your opinion solid scientific background ?

I would agree avoiding Warp drive kinda things, even though, there are finer points, that get your gears working, Advanced Space Propulsion Laboratory, later Ad Astra is rather 'conservative', if maybe a little more than 'Newtonian' , maybe some of the NIAC, Breakthrough Propulsion Physics Program projects ?

NASA page about Warp Drive (can't help it :roll: )
Warp Drive, When?
Breakthrough Propulsion Physics

This seams to be related:
Quantum Vacuum Energy
Maclay, G. Jordan, Jay Hammer, Rod Clark, Michael George, Yeong Kim, and Asit Kir. (2004) Study of Vacuum Energy Physics for Breakthrough Propulsion. NASA/CR–2006-213311

This report summarizes the accomplishments during a three year research project to investigate
the use of surfaces, particularly in microelectromechanical systems (MEMS), to exploit
quantum vacuum forces. During this project we developed AFM instrumentation to repeatably
measure Casimir forces in the nanoNewton range at 10−6 torr, designed an experiment
to measure attractive and repulsive quantum vacuum forces, developed a QED based theory
of Casimir forces that includes non-ideal material properties for rectangular cavities and for
multilayer slabs, developed theoretical models for a variety of microdevices utilizing vacuum
forces, applied vacuum physics to a gedanken spacecraft, and investigated a new material
with a negative index of refraction.

4. Gedanken Vacuum Powered Spacecraft
An attempt to address some of the key issues of the BPP program using the properties of the quantum vacuum was made in a collaboration between the PI and Robert L. Forward. A paper has been submitted for publication. A Gedanken spacecraft is described that is propelled by means of the dynamic Casimir effect, which describes the emission of real
photons when a conducting surface is moved in the vacuum with a high acceleration. The maintenance of the required boundary conditions at the moving surface requires the emission of real photons, sometimes described as the excitation of the vacuum. The recoil momentum from the photon exerts a force on the surface, causing an acceleration. If one imagines the moving surface is attached to a spacecraft, then the spacecraft will experience a net acceleration. Thus we have a propellantless spacecraft. However, we do have to provide the energy to operate the vibrating mirror. In principle, it is possible to obtain this power from the quantum vacuum, and this possibility is explored. Unfortunately with the current understanding and materials, the acceleration due to the dynamic Casimir effect is very small, on the edge of measurability.

We have demonstrated that it is possible, in principal, to cause a spacecraft to accelerate due to the dissipative force an accelerated mirror experiences when photons are generated from the quantum vacuum.

A model gedanken spacecraft with a single vibrating mirror was proposed which showed a very unimpressive acceleration due to the dynamic Casimir effect of about 3x10−20m/ s2 with a very inefficient conversion of total
energy expended into spacecraft kinetic energy. Employing a set of vibrating mirrors to form a parallel plate cavity increases the output by a factor of the finesse of the cavity, 1010, yielding an acceleration per meter squared of plate area of about 3x10−10m/ s2 and a conversion efficiency of about 10−16. After 10 years at this acceleration, a one square meter spacecraft would be traveling at 0.1m/ s. Although these results are rather unimpressive, it is important to remember this is a proof of the principal, and to not take our conclusions regarding the final velocity in our simplified models too seriously.

Experiment details:

Details of this experiment are given in [Maclay, J. Hammer, M.George, R. Ilic, Q. Leonard, R. Clark, ”Measurement of repulsive quantum vacuum forces,”
AIAA-2001-3359, AIAA/ASME/SAE/ASEE 37th Joint Propulsion Conference, Salt Lake City, 2001

http://www.quantumfields.com/AIAA2001.pdf

ABSTRACT
Quantum electrodynamics predicts that empty space (the quantum vacuum) contains a large amount of
energy that corresponds to the lowest energy state (energy >0) of the electromagnetic field. Surfaces in
the vacuum can experience forces that arise from the disturbance in the vacuum energy. The presence of
attractive “Casimir” forces between uncharged, parallel, metal plates has been accurately verified in
the last several years. Theoretical calculations have suggested the presence of repulsive vacuum forces
for certain geometrical configurations. Here we describe an experiment in progress that is designed to
determine if repulsive vacuum forces exist. In the experiment we measure the force exerted on a 200
um diameter metallized sphere mounted on an Atomic Force Microscope (AFM) that is placed very
close to an array of gold microcavities. Observing a repulsive force on the sphere would verify the
existence of repulsive forces. The ability to create attractive and repulsive vacuum forces by means of
the geometry of the surfaces may permit the construction of devices that use ubiquitous vacuum
energy in ways that assist with the space travel mission of NASA.

The Role of Quantum Vacuum Forces in Microelectromechanical Systems
http://www.quantumfields.com/usesofvacuum.pdf

Abstract
The presence of boundary surfaces in the vacuum alters the ground state of the quantized electromagnetic
field and can lead to the appearance of vacuum stresses. In the last 5 years, landmark
measurements of the vacuum stress between conducting uncharged parallel plates (Casimir force)
have been made employing Atomic Force Microscopes. The AFM provides a highly accurate optical
measurement of the deflection of a metallized sphere attached to the end of a micromachined
cantilever under vacuum forces as small as about 10 picoNewtons. The sphere deflects due to the
Casimir force as it is brought within about 20-700 nm of a flat surface. Recently the first micromachined
MEMS (microelectromechanical system) device was fabricated that utilizes the Casimir
force between parallel plates. The 1/d4 force dependence allows the device to serve as a highly
sensitive position sensor. The are many other examples of quantum vacuum forces and effects
besides the well known parallel plate Casimir force. Here we discuss potential roles of quantum
vacuum forces and effects in MEMS systems and other systems. With the growing capability
in nanofabrication, some of the roles may be actualized in the future. Because of the computational
complexity, no theoretical results are yet available for a number of potentially interesting
geometries and we can only speculate.

 

[neilsox]

The space elevator sort of fits the original post. The energy comes from slowing Earth rotation minutely. Another is electrically conducting tethers, The energy comes from minutely draining voltage differences in low earth orbit. Neil

 

[drwayne]

But what about a space elevator or a tether do you see as "defying Newton’s law of physics.", as the OP asked?

I think we may have drifted off of that portion of the topic into a discussion of new/novel concepts, whether they
satisfy the boundary conditions or not. But that it of course IMHO, and the original poster seems to have
disappeared from this thread.

 

[EarthlingX]

But what about a space elevator or a tether do you see as "defying Newton’s law of physics.", as the OP asked?

I think we may have drifted off of that portion of the topic into a discussion of new/novel concepts, whether they
satisfy the boundary conditions or not. But that it of course IMHO, and the original poster seems to have
disappeared from this thread.

There is a live discussion on this topic in 'Science Fiction' ...
It somehow started turned in that direction, or 'Unexplained', i was not sure ...
The Venture Star

Came from SB&T ..

Oh, and about the tether ... That's all good old Newton, i think, and that electro-thingy doesn't change it much.

 

[nec208]

Why do scientist get bad when people say Warp drive? Why is it such a hot topic?

And how can space ship run on electromagneti waves in space? Are there lots of electromagneti stuff in space the ship can run on?

Do stars and space gas give out electromagneti stuff the space ship can run on? And is Casimir effect/force stuff the black holes give out?

Why is Newton law so bad people are looking at other things for energy?

 

[Mee_n_Mac]

Why do scientist get bad when people say Warp drive? Why is it such a hot topic?

I'll assume you meant mad rather than bad above. I wouldn't say "scientists" get mad, rather people who understand physics dismiss the idea of travelling faster than light (FTL) which is what is implied when people say "warp drive". Right now there is no known way to have a spaceship that travels FTL. In fact there's quite abundant evidence that the present theory that states that FTL is impossible is correct. Now perhaps some day in the future someone will find an exception to present theory but right now we have to believe FTL is prohibited.

And how can space ship run on electromagneti waves in space? Are there lots of electromagneti stuff in space the ship can run on? Do stars and space gas give out electromagneti stuff the space ship can run on?

The is electromagnetic energy in space, you can see some of it in the light you see from the Sun and distant stars. Light, radio, microwaves are all forms of electromagnetic energy. It's not very powerful, at least not enough to propel the kind of spacecraft we have today. One way to use the EM energy is to have solar cells convert light into electricity to use to run various spacecraft instruments. This is pretty routine. We don't use this to propel the spacecraft. One way to use sunlight to propel a spacecraft is a solarsail. To date we have yet to test one successfully but give it a year and you may see at least 1 such test. Read more about this concept at the wiki ...

http://en.wikipedia.org/wiki/Solar_sail

And is Casimir effect/force stuff the black holes give out?

No.

Why is Newton law so bad people are looking at other things for energy?

I don't understand the question. If you mean to ask why are people looking for ways around "Newton's laws" to propel a spacecraft, it's because the laws of the universe make it ver hard to go from one planet or star to another planet or star. This is a long discussion in itself but an analogy might help. Pretend you are standing on a frozen pond and the ice is very, very, very slippery. So slippery that you can't walk anywhere because there's no traction between your shoes and the ice. The only way you can move is to toss balls from your backpack. Each time you toss a ball you move every so slowly in the opposite direction. This is an example of Newton's 3'rd law. To get anywhere on the pond in a reasonable amount of time you have to toss a lot of balls and toss them very hard to get up any reasonable speed. This is basically how a rocket works. Like a rocket, you can only toss the balls so hard and your backpack has only so much space for balls. This means there's a limit as to how fast you can get going and applying this to spacecraft it means they go very slowly for the very, very, very long distances involved.

http://en.wikipedia.org/wiki/Newton%27s ... efinitions

 

[nec208]

=======================================================================================
I'll assume you meant mad rather than bad above. I wouldn't say "scientists" get mad, rather people who understand physics dismiss the idea of travelling faster than light (FTL) which is what is implied when people say "warp drive". Right now there is no known way to have a spaceship that travels FTL. In fact there's quite abundant evidence that the present theory that states that FTL is impossible is correct. Now perhaps some day in the future someone will find an exception to present theory but right now we have to believe FTL is prohibited.
=======================================================================================


The scfi- shows are saying to get around this problem to travel faster than light is go in some other dimension or out of phase some kind of hyper window.Does any scientists thing this may work?

 

[drwayne]

"Why do scientist get bad when people say Warp drive? Why is it such a hot topic?"

I don't get mad at the discussion of such things. I do get somewhat perturbed when

(1) Something is said along the lines of "FTL is simple, all you have to do is *fill in incoherent word salad
that shows no understanding of even basic physics*, followed by a bunch of statements about how science
has turned a blind, dogmatic eye to the obvious correctness of the proposal for various nefarious reasons.

(2) A statement like "FTL has already been developed, but the world government/men in black/local savings
and loan are hiding it from the people.

 

[drwayne]

"The scfi- shows are saying to get around this problem to travel faster than light is go in some other dimension or out of phase some kind of hyper window.Does any scientists thing this may work?"

I would say that, given our current understanding of the way the universe works, such a process would not appear
to have a way to work to achieve what is so routine in the SF universe. However, it is of course possible that some aspect of our understanding is wrong. And despite what some on the fringe would suggest (scientists blindly
follow dogma and never consider anything really new), most scientists I know would love to show that something
that is understood as well established is in fact not right. That is how one makes the history books*.

Wayne

*that and moderating this forum

 

[drwayne]

If it is not obvious, I have been a sci-fi fan since I was a boy. I don't get to read as much these days,
and purists would laugh at what I do read, but, when you get old, people laughing at you is part of
the game.

 

[EarthlingX]

Note that I used the term - demonstrated, there are some - interesting ideas out there...

Can we continue from here ? :roll:

Anything we didn't mention ? I would like to know ...

 

[nec208]

I would say that, given our current understanding of the way the universe works, such a process would not appear to have a way to work to achieve what is so routine in the SF universe. However, it is of course possible that some aspect of our understanding is wrong.

The understanding of physics is nothing travels faster the light.The scfi-shows are saying to get around this is go in some other demotion or hyper window.But I'm not sure if physics talks about this.

Is is also my understanding to travel faster than the speed of light would need more energy than the universe has.And The mass of the object trying to travel faster than the speed of light the mass would get so big it would explode.


I do not know if physics have proven if other demotion or hyper window is real or not.Other thing with out a demotion or hyper window going the speed of light or faster may be so fast the ship can crach into a star ,planet or space rock.It is like going 300 KM down the city streets of LA not crashing into any thing.That going that fast with out an other demotion or hyper window may be very unsafe.

 

[dgwalker]

Thank you for interest in the question re electro-mechanical devices to propell spacecraft. This was a serious question as I am not convinced that this cannot be done. However I didn't want to waste time thinking about ways to do this if it is definately impossible or has been achieved already. There is mega bucks in cracking this one.

 

[drwayne]

"if it is definately impossible"

Important point that I have tried to make a couple of times. Given that something is considered
impossible given our current understanding of the way things work is NOT the same as saying
something is impossible.

Logically, it may be impossible, or it may be possible and we don't understand something. Or it may be that it
is impossible AND we really don't understand something.

 

[Littlefish]

Hi,

I've been thinking about a physical situation that looks like it should be a reactionless drive, but it seems far too simple to have been overlooked by science. I'll describe it below and maybe somebody will be able to explain why it won't work.

(1) Imagine a space station with a zero g room shaped like a riffle barrel. A man pushes-off from one end, imparting an acceleration to the station, sails to the other end and imparts an equal and opposite acceleration to the station.

That all cancels out.

(2) Now consider two men doing the same thing. One pushes-off at 2 meters per second, and the other pushes-off at 4 meters per second a moment later. As they pass, they grab hands and go into a rapid spin. When they let go they slam into the side walls instead of the end wall, seeming to spend some of their kinetic energy in the wrong direction.

I seems to me that the station would end-up with a net acceleration. The men could jump back to the start without imparting net acceleration as in scenario 1, then jump-off and repeat scenario 2 to increase the net acceleration.

I'm certain that this can't work, but I'd really like to know why. How can an equal and opposite reaction happen if some of the energy is expended against the side walls? Can anybody explain this in laymans terms?

 

[origin]

Hi,

(2) Now consider two men doing the same thing. One pushes-off at 2 meters per second, and the other pushes-off at 4 meters per second a moment later. As they pass, they grab hands and go into a rapid spin. When they let go they slam into the side walls instead of the end wall, seeming to spend some of their kinetic energy in the wrong direction.

I seems to me that the station would end-up with a net acceleration. The men could jump back to the start without imparting net acceleration as in scenario 1, then jump-off and repeat scenario 2 to increase the net acceleration.

I'm certain that this can't work, but I'd really like to know why. How can an equal and opposite reaction happen if some of the energy is expended against the side walls? Can anybody explain this in laymans terms?

There is an assumption that the 2 people in the spin will have no net motion which is wrong. If one person is moving at 2 m/s and the other is moving at 4 m/s (assuming they have the same mass) then when they grab hands they may spin but they will move as a pair in the direction opposite of the motion of the 'ship'. When they release regardless of their orientation there will be a combined net force that is opposite to the motion of the ship. It will all equal out to a net acceleration of zero. The conservation of momentum will once again win out.

 

[Littlefish]

...It will all equal out to a net acceleration of zero. The conservation of momentum will once again win out.

Of course you must be correct, else this effect would make itself felt all through physics. But your explanation leaves me no closer to understanding where the energy for those perpendicular vectors comes from if it isn't from the original force vector. This is probably not on topic and is not important anyway. It's just a nag to imagine a perpetual acceleration machine and not be able to disprove it.

 

[MannyPim]

...It will all equal out to a net acceleration of zero. The conservation of momentum will once again win out.

Of course you must be correct, else this effect would make itself felt all through physics. But your explanation leaves me no closer to understanding where the energy for those perpendicular vectors comes from if it isn't from the original force vector. This is probably not on topic and is not important anyway. It's just a nag to imagine a perpetual acceleration machine and not be able to disprove it.

This is a classic sticky collision problem. There is no mystery to it. It should be pretty easy to understand.
If the two men are of equal weight, when they meet and "stick together" whether rotating or not, they will have a net velocity of 1 meter per second in the direction of the guy who jumped off at 4 meters per second. If they remain "attached" they will eventually reach the other end of the tube and impart a momentum to the space craft that exactly cancels out the 2 meter per second net impulse.

This longitudinal velocity component is always there and it doesn't matter when they let go and fly off to the sides of the tube. If they fly off perpendicular to the side walls, they each will have a longitudinal velocity component of 1 meter per second (or exactly the same as if they never let go and hit the bottom end of the tube together). That longitudinal component will impart a momentum to the tube side walls which again will exactly cancel out the net momentum of the two guys jumping at different velocities.