from the is-an-EmDrive-twice-as-wide-as-an-EnDrive? dept.
German researchers have tested their own EmDrive design as well as a Mach Effect Thruster, finding that interactions between components and Earth's magnetic field may explain anomalous thrust:
The researchers – Martin Tajmar, Matthias Kößling, Marcel Weikert and Maxime Monette – presented their findings last week at the Aeronautics and Astronautics Association of France's Space Propulsion conference. The title of their paper is "The SpaceDrive Project – First Results on EmDrive and Mach-Effect Thrusters."
[...] The TU Dresden team constructed an EmDrive similar to the NASA test model. They stuck it in a shielded vacuum chamber and bombarded it with microwaves. They were able to measure thrust but it wasn't correlated with the direction the engine was pointing, leading them to conclude the test apparatus itself was affecting the measurements. They found that "magnetic interaction from twisted-pair cables and amplifiers with the Earth's magnetic field can be a significant error source for EMDrives."
The researchers will continue to conduct more tests, and will attempt to better shield the setup from interference, scale up the power, and add a missing dielectric disc component.
Meanwhile, NASA's Harold White has released another paper, Spacedrives and Conservation Laws. At a Breakthrough Discuss conference in April, he revealed plans to scale up to 400 Watts, and got grilled by Lawrence Krauss (video) and Robert Zubrin (same video) about the physics behind the device as well as a presentation slide assuming 400 times greater thrust per kilowatt than what Eagleworks observed, enabling "intersteller [sic] precursor" missions.
Also at Ars Technica, Phys.org, and Space.com.
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University finds prominent astrophysicist Lawrence Krauss grabbed a woman's breast
An investigation by Arizona State University (ASU) in Tempe concluded this week that high-profile astrophysicist and atheist Lawrence Krauss violated the university's sexual harassment policy by grabbing a woman's breast at a conference in Australia in late 2016.
"Responsive action is being taken to prevent any further recurrence of similar conduct," ASU's executive vice president and provost, Mark Searle, wrote in a 31 July letter to Melanie Thomson, a microbiologist based in Ocean Grove, Australia, who is an outspoken advocate for women in science. Thomson, who witnessed the breast-grabbing incident, received the investigative report from ASU's Office of Equity and Inclusion (OEI) and shared it with Science.
In response to an email asking what specific actions the university is taking, an ASU spokesperson wrote: "Professor Lawrence Krauss is no longer director of Arizona State University's Origins Project, a research unit at ASU. Krauss remains on administrative leave from the university. It is the policy of the university not to comment on ongoing personnel matters."
Lawrence M. Krauss and The Origins Project.
Related: Two EmDrive Papers -- Mach Effect Thruster, Too
(Score: 2) by mhajicek on Thursday May 24 2018, @06:09AM (4 children)
The Mass Effect thruster.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 4, Interesting) by BsAtHome on Thursday May 24 2018, @06:37AM (2 children)
Well, you simply jump and ever so slightly your mass will move.
Now, if we all go to the top of the mountain, then the rotational speed of the earth would decline and our days will get longer. Does this also mean we get to extend our lives? Must be a relativity question.
(Score: 0) by Anonymous Coward on Thursday May 24 2018, @06:48AM (1 child)
no. to lengthen your life, you need to go to the most intense gravitational field you can find, so sea-level would be better (I guess the South Pole would be ideal, since that's where the Earth is "dent").
(Score: 3, Informative) by takyon on Thursday May 24 2018, @07:13AM
Areas of Earth's gravitational field are not at a constant strength, but most of the fluctuations are due to water movement. NASA's GRACE data shows hot spots [nasa.gov]. GRACE-FO [nasa.gov] just launched and should provide better data.
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(Score: 1, Funny) by Anonymous Coward on Thursday May 24 2018, @07:01AM
> Still waiting for the Mass Effect thruster.
That's what *she* said!
(Score: 2) by Gaaark on Thursday May 24 2018, @10:14AM (2 children)
No. Tajmar has only shown that a signal that is about 50 times smaller than the expected emdrive thrust could be magnetic in origin.
--- https://www.blogger.com/comment.g?blogID=4637778157419388168&postID=6209683373889927133 [blogger.com]
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 2) by opinionated_science on Thursday May 24 2018, @11:06AM (1 child)
I got this too, from the *poor* article.
They *KNEW* they were publishing a mainstream rhetoric piece - at the *VERY* least they should have tried to mitigate their main point.
So another clickbait journal article. Quelle surprise.
(Score: 4, Informative) by Gaaark on Thursday May 24 2018, @09:24PM
Here's McCullough's rebuttal
https://physicsfromtheedge.blogspot.ca/2018/ [blogspot.ca]
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 2) by VLM on Thursday May 24 2018, @03:08PM
I skimmed the paper, missed that quoted line although I trust its a legit quote, I did get pissed off when reading where they found some positional error that they couldn't explain and handwaved it away as "must be a problem with twisted pair". Also kinda pissed that I found a line in the paper about they're gonna try next time with more than partial mu-metal shielding, WTF.
The problem is twisted pair, differential input amps on the pair, and mu-metal shielding IS the way to eliminate noise and errors. Maybe its some German to English translation thing and they actually wrote in German that they wired it all up with alligator clips a quarter mile from the legacy AM broadcasting transmitter and got a shitload of noise leading them to consider twisted pair or differential input amps for next time.
The thing with twisted pair is you get a sane-ish transmission line of predictable-ish impedance where induced noise tends to average out to the same on both conductors. We can build cheap differential input op amps that are darn near theoretically perfect such that the difference between the conductors can be output at a nice low impedance, maybe with some gain, in a low noise shielded cabinet. And for decades we've had mumetal you've probably seen it inside old fashioned CRT TVs. Its surprisingly expensive stuff and mechanically screwing around with it can change its magnetic shielding parameters a bit.
My point is if they asked an EE they could have gotten much better sensor input system rather than just chickening out with some "aw shucks" stuff about how it must be the wiring or opamp. What they're doing is harder than screwing around at my lab bench in my basement, but not a millionth as hard (yeah I throw down the gauntlet of 60 dB of SNR... feeling lucky? make my day... ) as what the metrology professionals at NIST and similar do all day long. In fact J Random Calibration Lab Bench Tech could probably help them quite a bit just by sheer osmosis of how to do it right.
I'm just triggered at the "they found that something is" but in the paper I read it was more like "aw shucks I donno why it ain't workin' must be the damn wiring" there's a subtle difference in tone and probably whatever they heck they said/wrote in German is a third totally different take on the topic which makes it even worse. A bad SN automobile analogy is there's a difference between shadetree guy listening to a misfiring engine and saying they donno whats wrong and he don't understand carbs so it must be the carburetor, vs a pro pulling a spark plug out and showing you the gap and insulator are demonstrably F'ed up so "physically worn out spark plugs can be a significant error source for misfiring engines".
(Score: 0) by Anonymous Coward on Thursday May 24 2018, @04:15PM (3 children)
let's just hope that if it works, that they add laser guns 'cause last i heard
downed earthian spacecrafts make great alien coral reefs in the alien planets ocean...
(Score: 2) by takyon on Thursday May 24 2018, @05:05PM
With all that mass saved from not carrying propellant, you could add plasma weapons.
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(Score: 2) by Snow on Thursday May 24 2018, @07:49PM (1 child)
I was watching a video on this test last night. Apparently they had the thruster mounted to a motor so they could change the orientation without opening the vacuum chamber. They move is this way and test, then move it that was and see if the results are as expected.
Eventually, they would generate the microwave signal, but instead of pumping it into the thruster, they would dump it to ground and they were still able to observe 'thrust'. That is a pretty damning result.
(Score: 0) by Anonymous Coward on Friday May 25 2018, @02:02AM
Dammit!!!