Science
Related: About this forumNasa validates 'impossible' space drive
Nasa is a major player in space science, so when a team from the agency this week presents evidence that "impossible" microwave thrusters seem to work, something strange is definitely going on. Either the results are completely wrong, or Nasa has confirmed a major breakthrough in space propulsion.
British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems, but critics reject his relativity-based theory and insist that, according to the law of conservation of momentum, it cannot work.
According to good scientific practice, an independent third party needed to replicate Shawyer's results. As Wired.co.uk reported, this happened last year when a Chinese team built its own EmDrive and confirmed that it produced 720 mN (about 72 grams) of thrust, enough for a practical satellite thruster. Such a thruster could be powered by solar electricity, eliminating the need for the supply of propellant that occupies up to half the launch mass of many satellites. The Chinese work attracted little attention; it seems that nobody in the West believed in it.
However, a US scientist, Guido Fetta, has built his own propellant-less microwave thruster, and managed to persuade Nasa to test it out. The test results were presented on July 30 at the 50th Joint Propulsion Conference in Cleveland, Ohio. Astonishingly enough, they are positive.
http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive
The infinite improbability drive is a wonderful new method of crossing interstellar distances in a mere nothingth of a second, without all that tedious mucking about in hyperspace. It was discovered by lucky chance, and then developed into a governable form of propulsion by the Galactic Government's research center on Damogran.
The principle of generating small amounts of finite improbability by simply hooking the logic circuits of a Bambleweeny 57 Sub-Meson Brain to an atomic vector plotter suspended in a strong Brownian Motion producer (say a nice hot cup of tea) were of course well understood and such generators were often used to break the ice at parties by making all the molecules in the hostess's undergarments leap simultaneously one foot to the left, in accordance to the theory of indeterminacy.
Many respectable physicists said that they weren't going to stand for this, partly because it was a debasement of science, but mostly because they didn't get invited to those sorts of parties.
Another thing they couldn't stand was the perpetual failure they encountered while trying to construct a machine which could generate the infinite improbability field needed to flip a spaceship across the mind-paralyzing distances between the farthest stars, and at the end of the day they grumpily announced that such a machine was virtually impossible.
longship
(40,416 posts)This is basic research, not warp drive engineering. This is no more "space drive" than the Casimir Effect, yet another one that has been promoted as a space drive.
To call it space drive is moonshine!
Horrible science reportage! Absolutely horrible.
The next thing they'll be claiming is that they'd be able to extrapolate the entire universe from a cupcake (in the UK, a fairy cake).
Pshaw!
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Ichingcarpenter
(36,988 posts)I added the Hitchhiker's guide segment as humour.
longship
(40,416 posts)My argument was against the horrible science reportage, not your post. As you see, I caught the Hitchhiker 's Guide allusion.
Nota bene: I am not Bowerick Wowbagger, the infinitely prolonged. I am not into insulting the universe.
Another HHGG allusion back at ya.
riqster
(13,986 posts)ET Awful
(24,753 posts)This has made a lot of people very angry and been widely regarded as a bad move.
newfie11
(8,159 posts)This would so be a game changer for this world and space exploration if it works out.
PeoViejo
(2,178 posts)It would be problematic to get into the shadow of Jupiter and have the thrusters crap-out.
krispos42
(49,445 posts)Like the ones on Voyager 2, for example.
Besides, don't worry... Isaac Newton will carry you through the shadow...
PeoViejo
(2,178 posts)DetlefK
(16,423 posts)1. No sketch of their device. No explanation how they conducted their experiments. BUT they show results.
2. No formulas. BUT they show the results of calculations.
And they have a picture of a spaceship-model!!!!
"google scholar" provides no relevant search-results for "emdrive"
And the article of Fetta on his Cannae-drive is behind a paywall.
intaglio
(8,170 posts)and a list of citations and papers with links
New Scientist has a PDF of the paper
It took me 30 seconds ...
DetlefK
(16,423 posts)Conservation of momentum exists only in a continuum that's independent of translation. But their wave-guide has conical form, which means that their system DOES change with a translation. Still, I wonder where we have to look to account for the momentum that's missing. There has to be some form of coordinate-system that would allow us to account for it.
For example: You are inside a train. That train is your reference-frame. Suddenly the train starts moving and an inner wall of the train moves and hits you, but to you it seems like you moved and you hit the wall. The momentum that slammed you into the wall has no counterpart inside your reference-frame because it's not translation-invariant. But if you look at the reference-frame that contains you AND the train, then you can account for both momenta and momentum is conserved.
WheelWalker
(8,954 posts)caraher
(6,278 posts)The theory makes no sense... and is clearly not peer-reviewed. It's amateurishness is clear from the whopping 3 references - a textbook, Maxwell and one journal article. Moreover, their very first equation (cited from the textbook) is clearly not at all understood by the writer!
This is the Lorentz force equation, rendered here as F = q(E + vB). Right away we have trouble - the F, E, v and B should all be vectors, and vB should be the cross-product v X B. This is not mere typographical laziness; the author reveals his ignorance of first-year E&M by saying
This shows that he has absolutely no clue what the Lorentz force equation is all about! It described the force on a charged particle (whose charge is q) moving with velocity v through a region of space where it experiences electric field E and magnetic field B. There is absolutely no reason to think this equation has any meaning at all when you're discussing the group velocity of microwaves (which have zero charge; applying this equation, if it leads to any prediction at all, would forecast zero force!).
It is written by someone who doesn't know what he is talking about. Ignore the theory. And anyone who would write such drivel I would not trust to perform a competent experiment, either.
intaglio
(8,170 posts)But ...
There seems to be independent experimental evidence that the effect exists. Now that may experimental evidence of the same sort that seemed to support Fleischmann and Pons but it remains evidence of an effect.
paleotn
(17,911 posts)....I'm extremely skeptical. Technically, I don't see how this could possibly work. Time will tell if this is some new phenomenon or cold-fusion like bullshit.
mindwalker_i
(4,407 posts)And frankly, I'm a bit skeptical. I'd really like to understand how it works (I'll be hitting new scientist in a few minutes), and how much force per unit power.
Johonny
(20,829 posts)it is hardly the first incredibly remarkable result I've seen presented at the JPC. NASA has funded things that haven't worked out in the end before so... just because it was at the JPC and NASA was involved doesn't mean you can't wait for more proof to jump on board. More than likely xenon based EP thrusters will continue to dominate the field and this thing won't pan out. Most truly remarkable things don't workout in the end.
groundloop
(11,518 posts)Instead of having a finite life due to running out of thruster fuel (I believe hydrazine is commonly used) which is required to counteract small wobbles in orbit or to slightly alter their orbit, this would give satellites a nearly unlimited life (or at least until something else fails).
Android3.14
(5,402 posts)It is encouraging that other groups are able to replicate the results, and to do so in a short time. That indicates this might be easier to build/control than a propellant engine.
DeSwiss
(27,137 posts)K&R
WinkyDink
(51,311 posts)eppur_se_muova
(36,257 posts)WinkyDink
(51,311 posts)tridim
(45,358 posts)Just drop a solar powered thrust module on the surface and let it go to work slowly altering the trajectory.
Festivito
(13,452 posts)Good here on earth, but useless in space without a constant gravitational vector unless there would be more than one working in concert!