NASA's reactionless thruster

[Disembodied]

NASA has published a peer-reviewed paper on an experimental reactionless thruster:

Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum

A friendlier summary of what might be going on is available here:
http://www.sciencealert.com/it-s-offici ... -published

But this might- might - be a breakthrough that could eventually make interplanetary travel a realistic prospect. A prospect fraught with peril and difficulty, granted , but at least one that doesn't mean lugging fuel all over the place.

[Cody]

Now if I could just have myself frozen until something like this becomes a reality. <sighs wistfully>
Wake me in a hundred years, rejuve my body, refresh my brain, and give me a new left foot.

[Smivs]

I'm not sure there will be much of anything left in a few hundred years time!
However, a way to flee the planet now would be nice....

[spud42]

i seem to remember a couple of years ago a private company or a university claiming to get thrust this way and all the mainstream scientists dismissing it.. its not much but constant acceleration adds up over time....

[Disembodied]

i seem to remember a couple of years ago a private company or a university claiming to get thrust this way and all the mainstream scientists dismissing it.

Fair enough, it does defy the Third Law of Thermodynamics … something that supposedly breaks a law that well established is almost certainly bogus. But fair's fair, NASA have tested it, and tested it, and had their research peer-reviewed, and published their results, and it seems to be working. This is science, doing what science should do.

If it does turn out to be true, there are two advantages, above and beyond interplanetary travel: first, it puts Elite: Dangerous's fuel-and-thrusters model in the bin where it belongs; and second, the pilot-wave theory of quantum mechanics which might be behind the whole thing knocks out the Copenhagen interpretation of Heisenberg's Uncertainty Principle, which if you ask me drives a horse and cart through Noel bloody Edmonds's Deal or No Deal.

[Cody]

If it does turn out to be true, there are two advantages, above and beyond interplanetary travel: first, it puts Elite: Dangerous's fuel-and-thrusters model in the bin where it belongs; and second, the pilot-wave theory of quantum mechanics which might be behind the whole thing knocks out the Copenhagen interpretation of Heisenberg's Uncertainty Principle, which if you ask me drives a horse and cart through Noel bloody Edmonds's Deal of No Deal.

<sniggers - twice>

[Cody]

According to El Reg, the Chinese think it works, and have sent one into space for testing.

[Redspear]

i seem to remember a couple of years ago a private company or a university claiming to get thrust this way and all the mainstream scientists dismissing it.. its not much but constant acceleration adds up over time....

...and I seem to recall some of us discussing it.

[Disembodied]

It's definitely got a lot of clever people interested …

This article, from the Atomic Rockets website, is worth a read, and has some good skeptical links about this specific engine too, under the "EmDrive" section:
http://www.projectrho.com/public_html/r ... sdrive.php

Friends Don't Let Friends Use Reactionless Drives In Their Universes.

Personally, I like reactionless drives, but the article does make a good point about their existence leading to the development of planet-shattering weaponry.

The trick is making a reactionless drive that doesn't give you the ability to shatter planets with the Naval equivalent of a rowboat (which would throw a big monkey wrench into the author's carefully crafted arrangement of combat spacecraft). Reactionless drives, with no fuel/propellant constraints, will give you Dirt Cheap Planet Crackers. If you have a reactionless drive, and stellar economics where most of the common tropes exist (privately owned tramp freighters), you also have gravitic drive missiles. Unfortunately avoiding Planet Crackers Done Real Cheap is almost impossible to justify on logical grounds, so SF author is faced with quite a daunting task.

Ultimately, I think here the lesson is, don't let the maths get in the way of the story. Maths is good, and I'm very appreciative of all the things that maths can do for us, but fiction is fiction, whether science- or not, and I'm willing to exercise a little bit of Suspension of Disbelief (or, more accurately, Suspension of Things I Didn't Know and Don't Really Understand Anyway).

However: if here in the real world, we have a genuine reactionless thruster, then we have perpetual motion. And planet-busting missiles.

Happy Christmas!

[Cody]

MAD for the interplanetary/interstellar age: you bust our planet, we'll bust your planet!

Happy winterfest!

[spud42]

but you dont need a drive at all to bust a planet. just bump a rock out of its orbit . if you can compute the trajectory for a planet strike with a reactionless drive then you certainly have the ability to do it with out one! the stars gravity is all the acceleration you need.

[Cody]

but you dont need a drive at all to bust a planet.

You do if you're aiming at those slimeballs on Proxima Centauri b.

[spud42]

but you dont need a drive at all to bust a planet.

You do if you're aiming at those slimeballs on Proxima Centauri b.

then you bump one of their rocks..... bump several .... do a Shoemaker Levy to them...lol

[Cody]

then you bump one of their rocks

Yeah... but you gotta get to their system to do that.

[spud42]

Ahh, but how do you know there are there unless you are close enough to their system to tell??