NASA validation of Cannae version of EMDrive produced power in the null test and a detailed look at China's version

The NASA report on the Cannae drive wasn’t much help either, since it only delved into the practicalities of testing one of the devices. At first glance, however, it looked quite interesting, stating, “Approximately 30-50 micro-Newtons of thrust were recorded from an electric propulsion test article.” If you push a bit further, it looks much less promising:

Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the “null” test article).

In other words, the negative control in the experiment worked. Which means that the experiment as a whole tells you nothing. Clearly, the device (even when disabled) appears to produce a force. But Lee suggested a variety of ways that this could happen and indicated that there are ways to monitor the device’s operation to see if any of them play a role (for example, he suggested that a mass imbalance of as little as 3 mg could account for the small force the NASA researchers found. “All in all,” Lee concluded, “it will take a lot more information before we can judge whether the thrust is really a thrust or not.”

The 2012 Chinese paper that produced power from an EMDrive device

Net thrust measurement of propellantless microwave thrusters.

According to classical electromagnetic theory, this paper introduces a new kind of propellantless microwave thruster device for use in space propulsion. This device is able to directly convert microwave radiation into thrust without the need for any propulsion medium. The difference with traditional space propulsion devices is that this system means there is no need to carry a large propellant tank, and the problems of plume emissions polluting the space craft can be eliminated. The system comprises a frustum microwave resonator, microwave source, and load. The microwave source produces microwave radiation which can be input into the frustum microwave resonator and form a pure standing wave and electromagnetic pressure gradient. Thus, along the axial direction of the frustum microwave resonator, net thrust is formed. This article, based on the indifferent equilibrium principle, overcomes the weight and rigidity resistance of the thruster itself, and successfully measures the net thrust produced by the propellantless microwave thruster. The results show that: Based on classical electromagnetic theory, creating a propellantless microwave propulsion system can produce a net thrust; when the microwave source output is 2.45GHz, with a microwave power of 80-2500W, the propulsion produced by the thruster is located in the range of 70-720mN, and the total measurement error is less than 12%.

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