In one minute

M. Tajmar, O. Neunzig and M. Weikert test the EMDrive, a proposed propellantless thruster in which microwaves in a closed tapered cavity would produce at least 1 mN/kW of thrust. Heat, mechanical load and large currents can create artefacts that look like thrust. They built an inverted counterbalanced double pendulum balance that removes most thermal drift, and ran the device on its own battery pack to avoid feedthrough interactions. Across a wide frequency band with several resonances and modes they found no thrust, limiting any anomalous thrust to below the force of classical radiation for the same power. The result sets strong limits for every proposed theory and rules out earlier test results by at least two orders of magnitude.

High-accuracy thrust measurements of the EMDrive and elimination of false-positive effects