The EmDrive has been heralded as the propulsion system that will revolutionize space exploration. But ultimately, it would be impossible to put into practice. Its inventor, however, is not of this opinion.
The concept of the EmDrive is based on the generation of fuel-less thrust with fully electric propulsion. The theoretical operation of the device consists in concentrating microwaves in a metallic resonant cavity to obtain a thrust. The mechanism uses Newton's second law. This explains that force is defined as the rate of change of momentum. "Thus, an electromagnetic wave moving at the speed of light has a certain impulse, which it will transfer to a reflector, causing minimal force" , explains the British start-up Satellite Propulsion Research.
The accumulation of a large amount of the force generated would then operate the EmDrive. This propulsion system uses no fuel. However, it requires an electric generator.
False positives according to German researchers
Bouncing microwaves in a resonant cavity generates a clean thrust in the absence of a propellant.
NASA and a Chinese team from Xi'an have announced more or less promising results after experiments. However, physicists at the Technical University of Dresden speak of false positives .
“ We were able to reproduce apparent thrust forces similar to those measured by the NASA team, but also to make them disappear by means of a point suspension. We achieved this through an improved structure. Our measurements refute all claims about EmDrive by at least 3 orders of magnitude, ”said Professor Martin Tajmar.
“ We found that the cause of the thrust was a thermal effect, ” Tajmar added. Data from the German team is available on ResearchGate.
A poorly designed resonant cavity according to Shawyer
Roger Shawyer is the inventor of EmDrive. He did not fail to comment on the conclusions of scientists at the German Technical University in Dresden.
“ The resonator used by Tajmar was poorly designed and it was never going to work. It's a flat end plate cavity to start with. If you do the simple geometry, you will see that you have a wavefront phase error approaching half a wavelength. You will never get moving waves in a flat front cavity. There are many other problems ”, defends the British aeronautical engineer. The response suggests that the EmDrive debates are far from over.