The latest paper, “Net Thrust Measurement of Propellentless Microwave Thruster,” is in the June edition of the journal Acta Physica Sinica published by the Chinese Academy of Sciences. Yang's team used a magnetron as a 2.45 GHz microwave source and produced a measured thrust of up to 720 mN from 2.5 kw of input power. On the surface, this appears to be a peer-reviewed validation of the science.
However, Yang says she is unable to answer questions from Aviation Week on her team's work at this time and is deferring until the end of the year for unknown reasons. Shawyer, meanwhile, has no doubts about its significance.
“The new paper independently proves the EmDrive theory by publishing thrust levels five times higher than SPR results, but with a similar specific thrust,” Shawyer tells Aviation Week.
The result, 720 mN, is just 2.5 oz. of thrust, but satellites often work with less. Boeing's advanced XIPS thruster, which fires out Xenon ions at high speed, achieves 165 mN of thrust from 4.5 lb. It weighs 35 lb., more than an equivalent EmDrive, and the propellant for prolonged operation can weigh much more.
XIPS and EmDrive can both run off solar electricity, but the EmDrive never runs out of propellant. Propellant to maintain satellite position is a major weight contribution; Shawyer suggests that the EmDrive could halve the cost of geostationary satellites.
There has been little interest in the EmDrive in the West so far, and Shawyer's government funding has ended. Boeing's Phantom Works, which has previously explored exotic forms of space propulsion, was said to be looking into it some years ago. Such work has evidently ceased. “Phantom Works is not working with Mr. Shawyer,” a Boeing representative says, adding that the company is no longer pursuing this avenue.
Still, the latest Chinese work may revive Western interest in the EmDrive as a viable, revolutionary technology.
“The EmDrive will give much higher performance, at lower cost, for many types of mission,” says Shawyer. “In an increasingly competitive, international industry, space companies will have to use EmDrive technology or go out of business.”