Leaked NASA Paper Suggests The 'Impossible' EM Drive Really Does Work (sciencealert.com)

A source close to NASA Eagleworks has leaked the test results of the 'impossible' EM Drive. While it's important to note that the results that have been leaked haven't been published in an academic journal, they do suggest that the system works and is capable of generating force of 1.2 millinewtons per kilowatt in a vacuum. ScienceAlert reports: The paper concludes that, after error measurements have been accounted for, the EM Drive generates force of 1.2 millinewtons per kilowatt in a vacuum. That's not an insignificant amount -- to put it into perspective, the super-powerful Hall thruster generates force of 60 millinewtons per kilowatt, an order of magnitude more than the EM Drive. But the Hall thruster uses fuel and requires a spacecraft to carry heavy propellants, and that extra weight could offset the higher thrust, the NASA Eagleworks team conclude in the paper. Light sails on the other hand, which are currently the most popular form of zero-propellant propulsion, use beams of sunlight to propel them forward rather than fuel. And they only generate force up to 6.67 micronewtons per kilowatt - two orders of magnitude less than NASA's EM Drive, says the paper. The NASA Eagleworks team measured the EM Drive's force using a low thrust pendulum at the Johnson Space Centre, and the tests were performed at 40, 60, and 80 watts. They were looking for any sign that the thrust could be a result of another anomaly in the system, but for now, that doesn't appear to be the case. "The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified," the team, led by Harold White, concluded in the paper. "Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 millinewtons per kilowatt." But the team does acknowledge that more research is needed to eliminate the possibility that thermal expansion could be somehow skewing the results. They also make it clear that this testing wasn't designed to optimize the thrust of the EM Drive, but simply to test whether it worked, so further tweaking could make the propulsion system more efficient and powerful.

Comments

This is interesting

[50000BTU_barbecue]

Because if Trump wins, we need a way to leave this planet...

Re: This is interesting

[Frankzy]

It'd make an excellent engine for anything that gets lifted into space and is supposed to stay there for a long time, such as satellites...

Re:This is interesting

[BlueStrat]

But its early days yet. We don't really know how it works. If it turns out to be a real thing, then physicists will have to mull it over for a couple of decades before new applications appear.

And if it's real, then once physicists have figured out how it work, they can get busy on increasing its efficiency. Getting to Mars in a week or Titan in a month vastly changes the economics of human expansion through the solar system.

Not quite. A bit of cart-before-horse.

Once there's enough testing done to prove it has potential, then engineers will take it, play with it, improve it, apply it, then sometime later, physicists and other scientists will figure out precisely why it works and why what the engineers did worked.

Strat

Re:This is interesting

[RockClimbingFool]

If Eagleworks has conclusive data that the EmDrive does indeed work, then there should be a Manhattan Project level of funding pushed towards it. It would change everything.

I blame 2016

[pushing-robot]

The physical laws went out the door months ago.

1/3 lightspeed

[Anonymous Coward]

Ran some numbers. Assuming the power generator and thruster itself has zero mass (obviously not, but it lets us set an upper limit), the energy available in 1kg of U235, at 1.2 millinewtons/kw, would accelerate that 1 kg mass to about 0.35 C, over the course of about 1000 days.

Add in mass of ship, generators and thrusters and you're looking at considerably less acceleration and top speed, but if this thing works at all (a big IF, granted), manned starships are just within the range of possibility. It'd still be a multi-year (probably multi-decade) trip, but hey.

Re: 1/3 lightspeed

[gringer]

Police Officer: "The light was red; you went through an intersection on a stop light"

Starship Officer: "It was green at the speed I was going"

Re:1/3 lightspeed

[mcswell]

I suppose the first thing we'd do if this worked would be to send out a bunch of unmanned probes towards interesting targets, and they would send back information as they cruised by these targets at 1/3 c. Earth is about nine light minutes from the Sun, so 1/3 c means you travel about 1 AU in a half hour. Assuming you start searching for Earth-like planets at a 2 AU out (you'd probably start sooner), the probe would have a couple hours in which to look around for planets, and take telescopic pictures (panning the telescope to compensate for motion during exposure) and other measurements of any planets found. That should be enough to determine whether it's worth sending a probe that would decelerate, or possibly humans. And the initial probe would either go off into empty space, or be re-directed to another star.

For Alpha Centauri, time to periapsis for a non-decelerating probe would be s.t over 12 years (not taking into account how long it takes to accelerate at 1/3 c, and assuming you don't try to accelerate faster than that). Four+ years to get the signal back. So we could know within 20 years whether it's worth exploring any given star system, although for the closest and most interesting targets I'm sure we'd send probes capable of decelerating immediately after the non-decelerating probes, just because we know so little about other stars.

I want to believe.

Re:I thought...

[imadeyoureadpoop]

I thought the science was settled on Newton's laws...

First rule of science: Science doesn't settle

Casimir effect

[Okian Warrior]

I thought the science was settled on Newton's laws...

Firstly, Newton's laws are based on observation and assumptions.

The observations gives us formulas that seem to fit, but there's no guarantee that those formulas describe all situations in the universe.

The assumptions, from Noether's theorem stating that symmetries imply conservation laws, are that the universe is smooth, in the mathematical sense of smooth being that space is infinitely divisible. We know that last part isn't true: you cannot measure position to an arbitrary precision in the universe.

It is therefore seen that Newton's laws become increasingly inaccurate when the scale is very large (relativity), or very small (quantum mechanics).

You might check out the Casimir effect some time.

It's not predicted by Newton's laws, but measurable and predictable using QM.

Anyone who says "EM drive cannot work because it violates my understanding of physics" should really check out the Casimir effect.

If your understanding of physics does not predict the Casimir effect, you probably shouldn't be commenting on the EM drive, or results from NASA rocket scientists.

Re:Casimir effect

[iris-n]

This is ridiculous. Conservation of momentum is valid in both quantum field theory and general relativity, there are an appropriate versions of Noether's theorem for them. And I don't see why are you harking about the Casimir effect: it doesn't violate conservation of momentum either.

Your suggestion that conservation of momentum might fail because of some fundamental discretization of space is also insane: first of all this is just speculative physics at this stage. Second, everyone that does speculate about it agrees that to probe the existence of this discretization would require particle collisions with energy around the Planck energy, about 10^28 eV. For comparison, the maximum we can do now, in the LHC, is to collide particles with energy of 10^13 eV.

To think that some lame tabletop experiment using only classical electrodynamics, running at most at 80 watts, somehow magically found a way to probe phenomena from an energy scale 15 orders of magnitude larger than the LHC scale, just shows a complete lack of knowledge of all the science involved. At the very least, it would show that the whole particle physics community are complete idiots for spending billions of euros in the LHC, while even more revolutionary science could by done on spare change by Eagleworks.

Re: That's easy. And it doesn't violate the 3rd pr

[Whatsisname]

That's not why the EM drive is neat. The force provided by emitted radiation is a fairly well understood and predictable phenomenon. The EM drive has a sealed microwave cavity, so it doesn't emit many photons, and those that it does through thermal radiation are measured and accounted for. Despite that, the EM drive appears to produce an additional force, that is what makes it neat.

Re: I thought...

[tylersoze]

Yes photons have momentum and a photon drive would be 1kW / 0.00334 millinewtons.

Re:I need to see more

[presidenteloco]

Here's a link to the NASA paper on the apparently successful test: https://drive.google.com/file/...

And here is a presentation by the technology's inventor, Roger Shawyer https://vimeo.com/channels/Emd...

Warning: Shawyer may well be brilliant, but he is the Anti-Musk in terms of his presenting and motivational skills. This guy could seriously announce a working warp drive in a way that would make people walk out of the presentation half way through. If he has funding problems, he needs to get someone else to present his technology and business case for him.

Actually, 0.043 c

[bwoneill]

I believe your math is wrong. U235 releases 202.5 MeV per atom undergoing fission, so that means 1 kg can generate 83.14 TJ from fission. Assuming 100% efficiency, a massless drive, and no mass loss from propellants, that means there is enough energy from fission to reach a velocity of 0.043 c relative to the rest frame.

dE = (m - m') c^2 = m' c^2 (gamma - 1) => m' c^2 = m c^2 (1 - dE/(m c^2)) = m c^2 (1 - rho)

rho = dE/(m c^2) = 83.14 TJ / 89.88 PJ = 9.25e-4

rho = (1 - rho) (gamma - 1) => gamma = 1/(1 - rho) = 1/sqrt(1 - beta^2)

(1 - rho)^2 = 1 - beta^2 => beta^2 = rho (2 - rho) = 1.85e-3

beta = sqrt(rho (2 - rho)) = 0.0430

Re:I thought...

[johannesg]

http://www.americanthinker.com...

http://www.killclimatedeniers....

http://www.climatedepot.com/20...

Calling upon the government to execute those with a different point of view is something I'd consider a death threat.

Re:I need to see more

[jandersen]

Well, if the drive works, then either the symmetry underlying conservation of momentum isn't entriely true (it wouldn't be the first time we discovered a surprising lack of symmetry, you know), or the drive isn't entirely reactionless. I think it is important to always be willing to keep an open mind, when we don't know for certain; what you are saying is "No, impossible, so I am not even going to look". Personally, I think preservation of momentum is true; so in my view there must be an escape of momentum that we haven't figured - if this works. This doesn't strike me as unthinkable - after all, energy is put in, so it must go somewhere. We just need to find an explanation.

take THAT, Slartibartfast!

[Thud457]

I would think a space drive powered by experimental error would be quite useful, considering what a unlimited resource it could tap.