10 upvotes, 3 direct replies (showing 3)
View submission: xkcd: Quantum Vacuum Virtual Plasma
No. The technology likely doesn't exist -- the anomalous test results likely arose from an unconsidered systematic bias.
The physicist quoted in this article does it more justice:
Also see the wikipedia article:
1: http://jalopnik.com/why-nasas-impossible-engine-is-likely-just-that-1616224512
To summarize, physicists use words like quantum vacuum, virtual particles, and plasma. The words don't seem to have an accepted meaning together.
But basically there was a test of a simple prototype (and a control for the prototype) both saw a small thrust on extremely sensitive equipment that seems to be anomalous. Note the tests were done in a vacuum chamber *at ambient pressure* (that is vacuum turned off) and the equipment is extremely sensitive (e.g., waves from bodies of water 25 miles away can affect measurements). And the type of thrust seen was on the order of the gravitational force of a single grain of sand. Finally, there were two drives tested -- one was configured in a way that it shouldn't have created any thrust by the framework that motivated someone to design these drives -- and both saw propulsion.
Science journalism trumps up the story, because the headline "scientist proves the impossible" is more attention grabbing then "Unknown systematic error in experiment -- researchers hard at work to pin it down". Sort of like the superliminal neutrinos detected at OPERA that turned out to be a systematic. Every scientist knew it didn't make sense due to special relativity, being a measurement of a few nanosecond delay (near the limits of sensitivity), and prior experimental results (SN1987a was 168,000 light years away and neutrino detectors on earth saw neutrinos consistent with the time of seeing the visible supernova if both neutrinos and light travel at c, but entirely inconsistent with them travelling faster than c). Later it was found out to be a cabling issue.
Comment by Anjin at 06/08/2014 at 18:54 UTC
4 upvotes, 1 direct replies
No, there were **3** test articles. One was the properly configured test - which produced thrust. The second was a test article that was changed in a way that was intended to make it not work *if a specific theory on how the reaction worked was correct* - which produced thrust, but less than the proper configuration (meaning that theory was wrong). The last was an RF load capable of accepting the power from the inputs to test the sensors to see if there were anomaly in the system's sensitivity - that one produced no thrust.
Comment by autowikibot at 06/08/2014 at 14:49 UTC
2 upvotes, 0 direct replies
2: https://en.wikipedia.org/wiki/EmDrive
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In July 2014, a NASA team at the Advanced Propulsion Physics Laboratory (informally known as *Eagleworks*) located at the Johnson Space Center (JSC) and led by physicist [Harold G. White](https://en.wikipedia.org/wiki/Harold_G._White_(NASA%5C[3])), reported on an evaluation of a RF resonant tapered cavity similar to Shawyer's EmDrive, with positive results.
3: https://en.wikipedia.org/wiki/Harold_G._White_(NASA%5C
Testing was performed on a low-thrust torsion pendulum[4] that is capable of detecting force at a single-digit micronewton level, within a sealed stainless steel vacuum chamber[5], but at ambient atmospheric pressure[6], because the RF power amplifier[7] used an electrolytic capacitor[8] not capable of operating in hard vacuum.
4: https://en.wikipedia.org/wiki/Torsion_pendulum
5: https://en.wikipedia.org/wiki/Vacuum_chamber
6: https://en.wikipedia.org/wiki/Atmospheric_pressure
7: https://en.wikipedia.org/wiki/RF_power_amplifier
8: https://en.wikipedia.org/wiki/Electrolytic_capacitor
NASA's tests of the tapered RF cavity were conducted at very low power (50 times less than Shawyer's 2002 experiment and 150 times less than the Chinese 2010 experiment) but a net mean thrust over five runs was measured at 91.2 µN at 17 W of input power. A net peak thrust was recorded at 116 µN at the same power level.
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^Interesting: ^Roger ^Shawyer[9] ^| ^New ^Scientist[10] ^| ^Quantum ^vacuum ^plasma ^thruster[11] ^| ^Reactionless ^drive[12]
9: https://en.wikipedia.org/wiki/Roger_Shawyer
10: https://en.wikipedia.org/wiki/New_Scientist
11: https://en.wikipedia.org/wiki/Quantum_vacuum_plasma_thruster
12: https://en.wikipedia.org/wiki/Reactionless_drive
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Comment by [deleted] at 06/08/2014 at 16:25 UTC
2 upvotes, 0 direct replies
It is telling that the "vacuum chamber" part was publicized widely, while the "at ambient pressure" part wasn't.