The EmDrive which made made headlines last year is back in the news with the results from a new set of tests by NASA showing that the drive has been successfully tested in a hard vacuum.
The EM drive is controversial in that it appears to violate conventional physics and the law of conservation of momentum; the engine, invented by British scientist Roger Sawyer, converts electric power to thrust without the need for any propellant by bouncing microwaves within a closed container. So, with no expulsion of propellant, there’s nothing to balance the change in the spacecraft’s momentum during acceleration. Hence the skepticism. But as stated by NASA Eagleworks scientist Harold White:
[T]he EM Drive’s thrust was due to the Quantum Vacuum (the quantum state with the lowest possible energy) behaving like propellant ions behave in a MagnetoHydroDynamics drive (a method electrifying propellant and then directing it with magnetic fields to push a spacecraft in the opposite direction) for spacecraft propulsion.
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Prior to this test there were many who believed that the resulting thrust measured during previous tests were due to thermal convection via microwaves heating the air surrounding the test drive. This seems to have been proven incorrect during the latest round of tests in a hard vacuum.
However, Paul March, an engineer at NASA Eagleworks, recently reported in NASASpaceFlight.com’s forum (on a thread now over 500,000 views) that NASA has successfully tested their EM Drive in a hard vacuum – the first time any organization has reported such a successful test.
To this end, NASA Eagleworks has now nullified the prevailing hypothesis that thrust measurements were due to thermal convection.
EmDrive Test Bed
The NASASpaceflight.com group has given consideration to whether the experimental measurements of thrust force were the result of an artifact. Despite considerable effort within the NASASpaceflight.com forum to dismiss the reported thrust as an artifact, the EM Drive results have yet to be falsified.
After consistent reports of thrust measurements from EM Drive experiments in the US, UK, and China – at thrust levels several thousand times in excess of a photon rocket, and now under hard vacuum conditions – the question of where the thrust is coming from deserves serious inquiry.
If this is truly the break through that it seems to be, it will result in a game change in space exploration.
New models show that the EmDrive acts as a three-dimensional magnetohydrodynamic flow of electron-positron virtual particles. This model also shows the reason for the discrepancy in thrust measurements in the NASA tests in respect to the tests run in the UK and in China.
The code shows two reasons for this: 1) the experiments in the UK and China used (unlike the ones in the US) a magnetron to generate the microwaves and 2) the experiments in the UK and China were performed with much higher input power: up to 2.5 kiloWatts, compared to less than 100 Watts in the US experiments.
In the US tests, microwave frequency generation was controlled via a voltage-controlled oscillator whose signal was passed to a variable voltage attenuator. The tests performed in the UK and China used, instead, magnetron microwave sources (as used in home-use microwave ovens) for their experiments.
The magnetron generates amplitude, frequency and phase modulation of the carrier wave (FM modulation bandwidth on the order of +/-20 MHz, at tested natural frequencies of ~2.5 GHz). Dr. White’s computer simulation shows that the modulation generated by the magnetron results in greater thrust force.
Computational model of EmDrive thrust
The model also shows that by increasing the input power results in focusing the virtual particle flow from near omnidirectional as shown in the NASA testing to a more focused beam at the higher power used in both the UK and China experiments.