Physicist John Baez has another, more colorful word to describe the spate of recent reports about a breakthrough space engine that produces thrust without any propellant. The word starts with “bull–.” I won’t finish it, this being a family-friendly web site and all. Baez himself has softened his tone and now calls it “baloney,” though his sentiment remains the same: The laws of physics remain intact, and the “impossible” space drive is, as far as anyone can tell, actually impossible.

The story begins several years back with a British inventor named Roger Shawyer and his EmDrive, a prototype rocket engine which he claimed generated thrust by bouncing microwaves around in an enclosed metal funnel. Since no mass or energy emerged from the engine, Shawyer’s claim was another way of saying that he’d found a way to violate the conservation of momentum. In Baez’s words, “this is about as plausible as powering a spaceship by having the crew push on it from the inside.” Shawyer argued that he was exploiting a loophole within general relativity. Baez calls his explanation “mumbo jumbo.”

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Now, on to the Cannae drive--could it be generating thrust through some novel means, sticking the momentum into some unknown form? Yes. But I am EXTREMELY skeptical that they've measured anything real. And their comments about interaction with some quantum vacuum virtual plasma is pretty much just word salad. Nobody outside of NASA Eagleworks (who did the testing) uses that term, which should raise some red flags right away.

First, they are trying to do a torsion balance test, which are known for being extremely tricky and finicky (see Impossible Thruster Probably Impossible for some details on that front). This was tested over only a few days and only a few times, which is not much time for trying to iron out all of the issues. I would want to see months of testing to confirm any sort of results. Did I mention that Science is Hard?

[Second - issues with testing in air ]

Third, their null test gave about as much thrust as their proper test. While one could argue that the null test was not "really" a null test as, since they don't really know how it works, maybe how they made it null (removing the slots) wasn't affecting it much, but it definitely kills their explanation of how it works (since their theory relied on the slots).

Fourth, this is a conference proceeding, not a paper. This means that nobody in the greater scientific community has formally vetted it (though now many are making comments in response to the news) and let me tell you, many many proceedings turn out to be wrong (I've caught mistakes in my own proceedings). These are more "interim" reports than anything final. So I'd give it fairly little scientific weight.

And, while this may sound a bit petty, the report looks sloppy, which does not inspire me with confidence. The fact that for their own proceedings they did things like take photos of graphs on their computer screens instead of downloading the data and putting it in nice graphs (which takes 20 minutes of effort, mostly to make the graph look nice): sloppy*. They talk about irrelevant things in the experimental set-up (like what sort of solder they used) and ignore important things like what the Cannae cavities are made out of (Copper? Or some kind of superconductor?). They have some inconclusive results and then end the report with some grand scheme of all the things that could happen if they scaled this up.

Just no.

This is the kind of thing I put out if I'm rushing to write a lab report for a class and am not putting too much thought into it. I will later accept the C grade and then never look at the report again. While you could have a shoddy paper for interesting results, this really does not instill any confidence in me that this test was undertaken with enough care and precaution to counteract all the sources of experimental error.

So I cannae vouch for the Cannae drive. Like the neutrinos we thought were faster than light (a measurement that was later found to be due to a loose wire) it's all too easy for these sorts of things to be some experimental hitch.

Science is Hard.

For more reading, I recommend John Baez's post: https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4

*Alternately, you could just press "Print Screen" on your keyboard, open up MS Paint, and crop the image to get something that looks nicer. That takes 30 seconds. IT TOOK MORE WORK TO TAKE THE IMAGES OFF OF A CAMERA LIKE THEY DID.

Culling Progress

To avoid the extremes of reflexive dismissals and
sensationalist hype common with revolutionary pursuits,
it is recommended to focus on the rigor and objectivity
of the concepts rather than trying to judge their
feasibility. An impartial feasibility assessment on
unfamiliar topics is as difficult as a research task unto
itself. Instead, the level of rigor is easier to judge.

Classic symptoms of non-rigorous work are
reflected in Langmuir “pathological science” [3],
Sagan’s “baloney detector” [4], Baez’s “Crackpot
Index” [5], and the lessons from the NASA
Breakthrough Propulsion Physics Project [1: Ch 22].
Representative symptoms from those sources include:

• Selectively addressing supporting evidence while
neglecting contrary evidence or the possibility of
false-positives.

• The magnitude of effect remains close to the limit
of detectability, along with claims of great
accuracy.

• Drawing conclusions from inadequate sample sizes
(Statistics of small numbers).

• Confusing correlation with causation.

• Lack of relevant reference citations.

The only test that will truly convince is putting one of these in a cubesat and sending it off to the Moon under thrust. However, I've read comments (unsubstantiated, so hearsay right now) that the inventors of the various drives (4 at last count) were all given the idea from observations of microwave communications satellites whose orbits were decaying faster than expected.