Tuesday, December 23, 2014

The Breakthrough Propulsion Concept Sanity Checker

Propulsion is, on the surface, a very simple science: I make a machine which uses stored propellants or some medium my vehicle is interacting with to generate a momentum exchange with my surroundings, thus making my vehicle move in the opposite direction. But once you dive into the details of any propulsion system you will quickly find that mastering this 'simple' science requires a lot of detailed knowledge: thermodynamics, fluid dynamics, chemistry, heat transfer physics, statistical mechanics, material science, electronics and of course rigid body mechanics and dynamics are essential. If you work with space propulsion odds are you will also need to know quite a bit about quantum mechanics, electrodynamics, and plasma physics as well. Put synoptically, it's really hard to make a completely new propulsion system which will be a fundamental 'breakthrough' in the field. Many have tried; most have failed. But that of course doesn't stop a wide variety of scam artists as well as honest-to-goodness crackpots from standing up and claiming they have a viable 'breakthrough' propulsion concept. Sadly these people can often find support both among laymen (who have little resources to distinguish viable new concepts from obviously spurious claims) and even propulsion engineers who may be specialized in a different area.

I've been getting tired of these claims being reported in the media and discussed as if they had any merit. Not only does this spread false information among non-experts, but it also takes time and reporting space away from true progress in propulsion. Imagine for instance if the coverage of the garbage NASA reactionless drive coverage I posted about in August had instead been dedicated to the co-development of a full-flow staged combustion rocket engine by NASA and SpaceX. Not only is this more interesting than a reactionless drive because it actually exists, but it's also more useful as a technology and the story gives a better picture of how the aerospace industry actually works. Thus in the hopes of assisting not only prospective inventors of 'breakthrough' propulsion concepts but also laymen and elsewhere specialized engineers, I've compiled a list of guidelines for any would-be propulsion innovator. If there's something that's not on here which should be please let me know in the comments!

The List:

1. If your breakthrough propulsion concept relies on unobserved or falsified physics, it is exceedingly likely to be spurious. 

2. if your breakthrough propulsion concept achieves delta-V without expending reaction mass, it is exceedingly like to be spurious. 

3. Indeed, if your breakthrough propulsion concept violates the conservation of momentum or angular momentum in a closed system in any way, it is exceedingly likely to be spurious.

4. No propulsion system can ever, ever, EVER lead to a macroscopic violation of energy conservation. EVER.

5. building on that last point, if your breakthrough propulsion concept violates ANY of the laws of thermodynamics, it is purely fictitious.

6. No Unobtanium Principle: If your breakthrough propulsion concept requires propellants, power sources, or materials which either do not currently exist or have been shown to not be able to exist, it is fiction until those materials become available.

7. Math is your friend. If you cannot present and justify simple, first-order performance calculations for your breakthrough propulsion concept, the odds are it is flawed or impossible. 

8. Fallacious and unjustified reasoning is not an "approximation", it's just wrong.  

9. Almost any concept relying on the "quantum vacuum" is exceedingly likely to be spurious, most likely due to the proposer not understanding the physics of the QFT vacuum. 

10. Conference papers which have not been peer-reviewed are not evidence of concept validity. Neither are websites, blog posts, articles in low-impact/poor quality/obscure/for-profit journals, non peer-reviewed articles on online repositories or publications, self-published books, angry letters or emails to legitimate propulsion researchers, snarky comments on websites/blogs/online publications, or abstract macaroni portraits of your idea. 

11. Your tests of your prototype of your breakthrough propulsion concept are not evidence of validity until (1) they are written up, peer-reviewed, and accepted for publication in a well-known, mainstream aerospace or propulsion journal, (2) they are successfully duplicated by other mainstream propulsion researchers, and (3) these successful duplications are themselves written up, peer-reviewed, and published in a well-known, mainstream aerospace or propulsion journal.

12. Test results reported without a rigorous propagation of uncertainty, comprehensive analysis of systematics, and a significant number of data points, are meaningless and can (and should) be dismissed without review.

13. Similarly, test results obtained at a low level of statistical significance do not validate nor falsify a concept.

14. Preparing a press release or giving a talk on your idea before submitting it for peer-review is tantamount to being so arrogant you think you don't need any feedback from your colleagues. Since the most arrogant people in any subject are usually the least capable (see the Dunning-Kruger effect) this is a valid cause for skepticism in and of itself.

15. Patents are not the same as peer-review, nor are they evidence of validity. Just because you have the legal right to patent your idea doesn't mean anyone else has to take it seriously. In truth any idea which is patented before it is constructed, tested, and peer-reviewed is likely to be spurious. 

Sunday, December 21, 2014

Walter Lewin Barred From MIT After Serious Allegations of Harassment

For those who don't know already, MIT professor emeritus Walter Lewin has been barred from MIT and his ties with the University cut after a secretive investigation of Lewin claimed he had violated MIT's sexual harassment guidelines during an online course. In the wake of the decision, all of Lewin's video lectures on physics have also been pulled from MIT's open courseware site and several press statements released. There is more detail here and another blog about it here.

If these allegations are true it is truly a shame. I remember watching Lewin's now famous basic physics lectures while I learned the same stuff from my much loved but sometimes overworked physics professor, Erik Kramer of the College of the Redwoods (known simply as "CR" to any Humboldt county native). Prof. Kramer's class, unlike so many physics courses, was something students looked forward to and he put a lot of his soul into making it as good as possible. This was sometimes hard to do at a small community college where he was the only physics professor and which had no money for any new lab equipment, often making lab sessions and demonstrations minimal. Those of us who were interested in physics, including myself and my friend Noah Flemens (now a grad student in applied physics at Cornell), would supplement Kramer's lectures with Lewin's from MIT and pretty soon the small group of 'physics kids' at CR were comparing and contrasting their "two favorite Dutchmen", though of course only Kramer could truly be thanked (or blamed) for how any of us turned out.

To hear the decision on Lewin is heartbreaking and I don't think it's right that MIT is being so secretive regarding the evidence which pushed them to dismiss a legend in physics education. Sources I found say it was clear the incidents were real and serious and this may be true, but it is no more than hearsay until we are given something--anything--to back it up beyond MIT's word.

Another bizarre decision is MIT's removal of Lewin's physics lectures from their Open Courseware website. In my opinion this is one of the best ideas MIT has had in a long time and one of the only things keeping them relevant in a world where their prestige is based more and more on their brand rather than their research quality (aside: I could write multiple posts about my view on 'big' school brands but now's not the time). Lewin's lectures were undoubtably some of the best on Open Courseware and recent events don't change that. Instead it robs the world at large from hearing good, well put together lectures on basic physics, and is MIT breaking a promise they (very publicly) made to the world at Open Courseware's inception.

Thus it seems as if MIT has two responsibilities in dealing with this incident: (1) make public the evidence of Lewin's harassment; for those of us who once idolized him as a teacher, it's the least they could do. (2) restore Lewin's lectures to Open Courseware. These lectures in and of themselves have nothing to do with this incident and it is pointless to punish those who would like to learn more about basic physics for inappropriate things the presenter may or may not have subsequently done.

Friday, August 15, 2014

"Measurements" of Anomalous Thrust: Using a conference paper as a way to cheat peer-review?

Anyone who follows tech news has undoubtedly heard some headline isomorphic to "NASA has validated a new space drive that defies the laws of physics!!!" by now. This came about shortly after the self-proclaimed "Eagleworks Laboratories" at NASA's Johnson Space Center presented a paper at the Joint Propulsion Conference this year, where they claimed to have measured microthrust coming from two devices similar to the infamous EmDrive of Roger Shawyer. Anyone who understands basic physics can clearly see the device is non-thrusting, or otherwise would violate the conservation of momentum, and both Eagleworks' "results" and 2013 "results" from a Chinese team also violate the conservation of energy (you can calculate this by looking at the equivalent thrust to power ratio produced by a photon rocket and compare the numbers to those Eagleworks and the Chinese reported). Yet Eagleworks, whose "research"--all of it-- is questionable at best, was able to present at a major conference a paper so bad it would make even the most dour reviewer laugh out loud. 

Despite the overwhelming credulity from the blogosphere and social media that inexorably comes with the mention of "NASA" there is now a number of good posts explaining issues with Eagleworks' experiment. A good one with a quote by my favorite physicist Sean Carroll is here. Carroll's response to the weird and nonsensical claim by Eagleworks, that their device is potentially producing thrust by interacting with a semi-mystical "quantum vacuum virtual plasma", is simply too well put not to reproduce:

“There is no such thing as a ‘quantum vacuum virtual plasma,’ so that should be a tip-off right there. There is a quantum vacuum, but it is nothing like a plasma. In particular, it does not have a rest frame, so there is nothing to push against, so you can’t use it for propulsion. The whole thing is just nonsense. They claim to measure an incredibly tiny effect that could very easily be just noise.”

The physicist John Baez, author of the hilarious and all too true Crackpot Index, has two posts explaining the flaws of the design and experiment (firstsecond). Sadly no space engineers, besides myself, have yet challenged Eagleworks' claim, despite the fact that it makes a mockery of our field.

After reading some of the credulous (and skeptical) pieces and becoming incensed, I wrote to the AIAA, who lead the JPC and therefore would have been responsible for allowing Eagleworks' nonsense to be presented without review. I asked them if I could submit a technical comment for a conference proceeding, challenging the claims of Eagleworks and explicating the flaws of their nonsense experiment in full. This is routine for a normal, peer-reviewed paper in a journal, but is not typically done for conferences. After a few days the answer was clearly 'no' which made me even more incensed. This was not helped by their associate's claim that the paper was "unpublished" by the AIAA, despite the fact that an e-copy is hosted on an AIAA server! 

How is our field supposed to maintain its credibility when the lines can be blurred so easily? In these days of high publication demands by employers--even some in industry--many respectable engineers use conference proceedings as publications on their CVs. But crackpots, such as Eagleworks, can also submit and present their drivel, all apparently with impunity from peer-review. How can fringe work be filtered out from real, valid research if the submissions to conferences which we increasingly rely upon for results are not reviewed? Although the anomalous thrust incident appears to most skeptics as a small skirmish in a larger war against the public misunderstanding of science, I see it as revealing a gapping hole in astronautics' wall of separation between legitimate research and crackpot ideas. To me this incident, the amount of media attention it got, and the AIAA's refusal to retract or allow rebuttal to the paper indicates that anyone can now use the JPC (and possibly other conferences) as a way to cheat peer-review and also be shielded from any formal criticism within the publications of the same professional organization. 

This is a sad perversion of the noble goals for which these conferences were first started and we as a community ought to think of a way to end this abuse of the conference system and the peer-review process. I am confident Eagleworks will eventually try to present more and more of their garbage as legitimate science and will exploit this conference paper loop-hole to do it. The bigger and bigger the claims get, the more and more people will begin to expect science-fiction style technology which has no way of being delivered in reality. When it isn't they'll blame NASA and the whole field will suffer for it. Meanwhile we will have opened the floodgates to every crackpot propulsion idea in the world. Is this really what propulsion engineers want? Probably not. It's time we started reviewing conference submissions.

Saturday, July 5, 2014

Just a Bit of Rocket Science

It's only rocket science and not even a lot of rocket science. It's just a bit of rocket science and the rest is counting beans, pennies, unhatched chickens, and whatever else you can fit into a quarterly report.

It's electronics and code. Sure. It's wiring up a little gizmo to test another gizmo that might be used to validate the concept for a subsystem in an engineering model which they're gonna build half-way across the country five years from now. But if there's any rocket science it will be just a bit of rocket science and it's nothing you need to be worried about.

It's project planning. Yes. It's planning to plan for implementing a ConOps under five different circumstances for each subsystem. It's planning for an engineer who needs to remake a harness three times before he gets it right. It's planning for the systems engineer to walk in and say she has a new plan and so no one needs to worry about that harness anymore, which the project manager has to plan for in itself. But you don't really need to plan any rocket science, and if for some reason you do if will be just a bit of rocket science and you can just consult the systems spreadsheets and find a place to squeeze it in.

It's testing. Of course. It's testing everything in every way and then some. It's coming up with failure modes God himself couldn't and then a way to fix them with three pipe cleaners, superglue, and a rubber band (and it's making sure there's an extra pipe cleaner just in case). But you don't need rocket science for testing, and even if you do it will be just a bit of rocket science and you can review the literature to learn it.

It's documentation. Without a doubt. It's documenting the fact that you documented the interface between a plug and an outlet which was used by an intern on the third floor for a week three months ago. It's documenting the conversation you had half-drunk at the bar with your PI about potentially contacting a company to help manufacture the chassis for a payload instrument which wont be finalized for another 4 years and 6 reviews. But if you have to document any rocket science, it will be just a bit of rocket science and its going to be vetted and expanded by eight other people so you don't need to write too much about it.

It's reviews. Absolutely. It's having to do N+1 PDRs, CDRs, and FRRs after you've already done N for all numbers N. It's making slides and wearing your nicest suit. It's public speaking. It's humoring dumb questions and faking your way through good ones. But no one's going to ask you about rocket science because no one wants to hear about rocket science and plus everyone knows rocket science already so why would they need to ask you? But if for some unimaginable reason they do ask you about rocket science it will be just a bit of rocket science and you really shouldn't go overboard.

And then, at the end of it all, you fly out to the launch facility and see your work ready to be fired upward at hundreds of times the force of gravity. Your heart jumps into your mouth as they count down for what seems like an eternity, until finally the motors ignite and the launch vehicle, pristine and elegant, raises itself into the sky and finally beyond. And at that moment you realize it was rocket science, every bit of it. You realize you and everyone else did a lot of rocket science with just a bit of rocket science, and that rocket science wasn't as simple an idea as it had been made out to be. Because it's not explosions, or engines, or nozzles that make rockets. It's people, it's politics, it's reviews, it's documentation, and it's everything you ever learned in science and math and then some. It's just a bit of rocket science and a lot of everything else in life, the universe, and everything.