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Forum Index : Other Stuff : Microwave thrusters

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vasi

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Posted: 03:08am 03 Aug 2014
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A new space propulsion system in full development at NASA.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2014000 6052.pdf
The British guys were the first ones to discover it, followed by China with some results.
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norcold

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Posted: 12:23pm 03 Aug 2014
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Do I understand this correctly, thrust was "basically" produced by radio waves? Have to bolt my trannie down. Jokes aside, is exciting stuff.
We come from the land downunder.
Vic
 
Gizmo

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Posted: 12:29pm 03 Aug 2014
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Yeah read about this a couple of days ago. Not much thrust, but the first ion drive didn't have much thrust either. Ions drives got better, and are in use today, but still need a "fuel", that is, something to throw away from the craft to provide thrust in the opposite direction. This gives the ion drive a limited duration.

This new microwave drive needs no fuel as such, so in theory could run for years using electricity from solar cells.

Here's something to think about. If you took a everyday torch, turned it on and put it in space, would it move off in one direction? There would be radiation and photons coming from one end, would this provide thrust? From what I gather, no, as light photons have no mass. If it did work, then we would see development in light drives instead of ion drives or microwave drives.

But a solar sail does work, where light bounces off a reflective surface. Its pushed by light, but not the photon part. ?

See where this is going?

If a torch has no thrust ( I believe, but could be wrong ), but the light from a torch could move a sail, then what would happen if attached a torch to the sail, so its light was reflected off the sail?


The best time to plant a tree was twenty years ago, the second best time is right now.
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norcold

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Posted: 01:08pm 03 Aug 2014
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Thought stimulating, but does a photon have no mass? Of course there are arguments that they have as below.
Mass of light
and then another read I had a while back that suggested, that light was limited to "light speed" because it had mass wheras "theoretically" radio waves having no mass ??? can be "forced" to travel much faster than the speed of light. Black holes emitting to white holes light years apart, instantaneously, sort of thing. Casual read then must check out.

We come from the land downunder.
Vic
 
Pete Locke
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Posted: 09:45pm 03 Aug 2014
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Well if they want to open the door on a microwave oven and point it towards the outer reaches of space, good on them . A magnitron needs a couple of KV to work (assuming standard construction) although only a few milliamps. It's a valve. A cathode with an oxide coating which doesn't last a long time if it's driven hard. But good skills to examine that as an alternate to ION propulsion. Interesting article on 'Mass Of Light'. Does light travel in waves of as particles? Well that debate is on going with theory and examples of both to disprove the other. Key point is, if a photon is not moving, is it a photon? That's a mind bender . Assuming everything travels in waves from the point of origin then you could start by looking at a stone thrown into a pond. You can see the pattern easily. Now tighten the waves up (raise the frequency) and eventually they will pass through our audio spectrum via air compression. Carry on up in frequency again and eventually you will get through the R.F spectrum and into infra-red heat area and on through our perceivable vision area. But that's if you go the wave theory way. Particle theory is whole other ball game. I like beer. Bubbles of CO2 travel up as a visible particle, and make small waves on top of the brew as they make the surface. This is proof that particle and wave theory can co-inside in one space
 
norcold

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Posted: 10:26pm 03 Aug 2014
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I guess man has throughout time been a wee arrogant in believing he has the answers, no different now although we have progressed heaps in a century it is possibly nothing compared to how we progress in the next century. But it seems it is one genius that comes along with each generation that influences our progress more than all the think tanks combined.

Propulsion of space vessels at better than light speed a necessary to get us out into the stars, all of interest but for now those CO2 bubbles in our beer are worth studying more closely
We come from the land downunder.
Vic
 
vasi

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Posted: 02:35am 04 Aug 2014
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Could this be a light reflected propulsion system, a microwave or a combination of both? Can't wait to see it happen in my life time. But instead of saying "now I can die in peace" I would definitely say "now let me ride it" (I guess someone said it before)! Why? Along with civilization progress, population increase and vital space reduction, it came also an awful liberty limitation. So, can't wait to evade in space! Terra is too crowded for my taste Edited by vasi 2014-08-05
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Tinker

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Posted: 03:19am 04 Aug 2014
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  Gizmo said  

If a torch has no thrust ( I believe, but could be wrong ), but the light from a torch could move a sail, then what would happen if attached a torch to the sail, so its light was reflected off the sail?



Nothing, for the same reason that a fan mounted on a sailboat and blowing into the sails on a windless day does not produce any propulsion.

I think the "for every action there is an equal and opposite reaction" also implies in space.
Klaus
 
vasi

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Posted: 03:34am 04 Aug 2014
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  Tinker said  
  Gizmo said  

If a torch has no thrust ( I believe, but could be wrong ), but the light from a torch could move a sail, then what would happen if attached a torch to the sail, so its light was reflected off the sail?



Nothing, for the same reason that a fan mounted on a sailboat and blowing into the sails on a windless day does not produce any propulsion.

I think the "for every action there is an equal and opposite reaction" also implies in space.


But your sailboat is in a gravitational context and has to overcome resistance and friction...
Anyway, is not the same. Your fan generate propulsion from the start. There it happens at a different stage.Edited by vasi 2014-08-05
Hobbit name: Togo Toadfoot of Frogmorton
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Greenbelt

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Posted: 05:29am 04 Aug 2014
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I have a Light Bulb,(Torch") I Guess, That has been in use for 17 years in a
Microwave Oven, "Sharp".
I suggest that in all that time it has emitted enough Photons to equal the mass of the
total Glass Shell and Filament. It still functions and is apparently as built.

Also, an LED would destroy itself in a few weeks if a photon was a particle.

Cheers,-------------Roe
Time has proven that I am blind to the Obvious, some of the above may be True?
 
vasi

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Posted: 07:29am 04 Aug 2014
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The Solar Sail Demonstrator will launch on a Falcon 9 in 2015.

And there is also Electric Sail
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vasi

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Posted: 07:32am 04 Aug 2014
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But we already have launched spacecrafts with solar sail in space and one is IKAROS.

________
I found what I searched for: Laser propulsion.
And Solar electric propulsion from NASA's site. Edited by vasi 2014-08-05
Hobbit name: Togo Toadfoot of Frogmorton
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norcold

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Posted: 08:53am 04 Aug 2014
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The understanding that individuals like Kepler had in their age, makes you wonder just what they could achieve if alive now.
Let us create vessels and sails adjusted to the heavenly ether, and there will be plenty of people unafraid of the empty wastes."
--Johannes Kepler, 17th-century astronomer
and today we have Pekka Janhunen of Finland to further Kepler`s vision combined with Einsteins Space-time relativity theory, some of our laws of physics are being tested and shown that they may be incorrect or bent a little, especially our understanding of time. Appears it may not be the constant we believe it to be. Very hard for this vegemite to get my head around.
Black holes and there opposite white holes
We come from the land downunder.
Vic
 
Gizmo

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Posted: 12:32pm 04 Aug 2014
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  Tinker said  
  Gizmo said  

If a torch has no thrust ( I believe, but could be wrong ), but the light from a torch could move a sail, then what would happen if attached a torch to the sail, so its light was reflected off the sail?



Nothing, for the same reason that a fan mounted on a sailboat and blowing into the sails on a windless day does not produce any propulsion.

I think the "for every action there is an equal and opposite reaction" also implies in space.


True, but what I'm thinking is, if a light source has no thrust therefore provides no push in the opposite direction, but light bouncing off a surface can in fact push it, then maybe it would work. This is different to the fan facing a sail scenario, both on a fixed object ( the boat ) because both the sail and fan are pushing, and it cancels out. But if a light source can provide a stream of photons, without any thrust?

I'm sure there is a scientific reason for it not to work.
The best time to plant a tree was twenty years ago, the second best time is right now.
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yahoo2

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Posted: 03:06pm 04 Aug 2014
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I feel like you guys are just baiting me up waiting to see if I will bite here.

every calculation for radiation pressure takes into account pressure from reflection and emission in 3 dimensions.

There is no asterisk with a note down the bottom saying "excluding torches". What there will be is a large proportion of the pressure from radiation from a torch will be low frequency radiation like IR that is not focused by the reflector and will be emitting from all parts of the torch so the resulting net pressure in the direction of visible light will be very small as a percentage of the total.
I'm confused, no wait... maybe I'm not...
 
norcold

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Posted: 03:43pm 23 Aug 2014
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The torch beam used to propel, got me looking through the internet for a simple explanation as to if it is possible. NASA and other reputable sites list papers that prove it is true but this one I found from Cambridge explains it more simply, to me.

YORP effect
We come from the land downunder.
Vic
 
Pete Locke
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Posted: 11:31pm 23 Aug 2014
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www.youtube.com/watch?v=cey-JBeHrww Motion by light. Been about for years
 
norcold

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Posted: 11:08am 24 Aug 2014
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That is a neat demo, Utube to the rescue. You gotta love the info highway..
Thanks Pete
We come from the land downunder.
Vic
 
Pete Locke
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Posted: 12:16am 25 Aug 2014
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Hehe...Yes I know it's more about thermo dynamics than anything else, but given space is about as close to a perfect vacuum as you will find, imagine heading off into the great black abyss armed with a Radiometer driving a 2km wide propeller making use of the solar winds powered my an LED flash light and enough spare batteries to go the distance. Might be more efficient that a microwave oven with its door open being powered by a very long extension lead. See, blowing wind at a sail with a fan on the boat you're on CAN work. As long as you are in a vacuum
 
Tinker

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Posted: 03:58am 25 Aug 2014
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  Pete Locke said   See, blowing wind at a sail with a fan on the boat you're on CAN work. As long as you are in a vacuum


Well, it might if there was a *wind* in the vacuum. Since a vacuum means any absence of air and wind is basically moving air the fan will still do nothing to propel a sailboat in a vacuum.
Klaus
 
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