from the it-shouldn't-work-but-does dept.
This story from a Wired article: NASA is a major player in space science, so when a team from the agency this week presents evidence that "impossible" microwave thrusters seem to work, something strange is definitely going on. Either the results are completely wrong, or Nasa has confirmed a major breakthrough in space propulsion.
British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems, but critics reject his relativity-based theory and insist that, according to the law of conservation of momentum, it cannot work.
NASA states... "Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma"
An article at NasaSpaceFlight.com is claiming that the superficially reactionless EmDrive has again been tested at NASA Eagleworks, this time in hard vacuum, and the anomalous thrust is still being detected:
A group at NASA's Johnson Space Center has successfully tested an electromagnetic (EM) propulsion drive in a vacuum – a major breakthrough for a multi-year international effort comprising several competing research teams. Thrust measurements of the EM Drive defy classical physics' expectations that such a closed (microwave) cavity should be unusable for space propulsion because of the law of conservation of momentum.
With the popular explanations of thermal convection or atmospheric ionization being ruled out by operation in vacuum, and thrust thousands of times greater than expected from a photon rocket, is it time to start taking the EM Drive seriously as a fundamentally new form of propulsion, and possibly a door to new physics?
After months of speculation and leaked documents, NASA's long-awaited EM Drive paper has finally been peer-reviewed and published [open, DOI: 10.2514/1.B36120] [DX]. And it shows that the 'impossible' propulsion system really does appear to work. The NASA Eagleworks Laboratory team even put forward a hypothesis for how the EM Drive could produce thrust – something that seems impossible according to our current understanding of the laws of physics.
In case you've missed the hype, the EM Drive, or Electromagnetic Drive, is a propulsion system first proposed by British inventor Roger Shawyer back in 1999. Instead of using heavy, inefficient rocket fuel, it bounces microwaves back and forth inside a cone-shaped metal cavity to generate thrust. According to Shawyer's calculations, the EM Drive could be so efficient that it could power us to Mars in just 70 days.
takyon: Some have previously dismissed EmDrive as a photon rocket. This is addressed in the paper along with other possible sources of error:
The eighth [error:] photon rocket force, RF leakage from test article generating a net force due to photon emission. The performance of a photon rocket is several orders of magnitude lower than the observed thrust. Further, as noted in the above discussion on RF interaction, all leaking fields are managed closely to result in a high quality RF resonance system. This is not a viable source of the observed thrust.
[...] The 1.2 mN/kW performance parameter is over two orders of magnitude higher than other forms of "zero-propellant" propulsion, such as light sails, laser propulsion, and photon rockets having thrust-to-power levels in the 3.33–6.67 μN/kW (or 0.0033–0.0067 mN/kW) range.
Previously: NASA Validates "Impossible" Space Drive's Thrust
"Reactionless" Thruster Tested Again, This Time in a Vacuum
Explanation may be on the way for the "Impossible" EmDrive
Finnish Physicist Says EmDrive Device Does Have an Exhaust
EmDrive Peer-Reviewed Paper Coming in December; Theseus Planning a Cannae Thruster Cubesat