Paul March indicated on the NASA Spaceflight forum that NASA Eagleworks is getting another EMDrive paper through peer review.
Paul March also endorsed the technical information and insights of forum member Rodal on the topic of EMdrive. Rodal indicates the differences in dielectric materials and other nuances of interpreting the known results.
A radio frequency (RF) resonant cavity thruster is a proposed new type of electromagnetic thruster. Unlike conventional electromagnetic thrusters, a resonant cavity thruster would use no reaction mass, and emit no directional radiation.
A few variations on such thrusters have been proposed. Aerospace engineer Roger Shawyer designed the EmDrive in 2001, and has persistently promoted the idea since then through his company, Satellite Propulsion Research.
Chemical engineer Guido Fetta designed the Cannae Drive, based on similar principles. If they are found to work as claimed, providing thrust without consuming a propellant would have important applications to all areas of propulsion.
Some independent teams of scientists, notably a team at Xi'an's Northwestern Polytechnical University (NWPU), one at NASA's Eagleworks laboratories, and another at the Dresden University of Technology in Germany, have built prototypes of these designs. The NWPU team reported a small but significant thrust; NASA Eagleworks reported a much smaller thrust than the NWPU team; and the Dresden team reported a small thrust, but within experimental error.
In 2014 and 2015, the NASA Eagleworks research group at Johnson Space Center tested models of both the EmDrive and Cannae drive. They reported observing a small net thrust from both, at low power levels.
NASA's first tests of this tapered RF resonant cavity were conducted at very low power (2% of Shawyer's 2002 experiment and 0.7% of the Chinese 2010 experiment), but a net mean thrust over five runs was measured at 91.2 µN at 17 W of input power. A net peak thrust was recorded at 116 µN (about 0.0004 ounces, or approximately the same weight as a grain of rice) at the same power level. The experiment was criticized for not having been conducted under vacuum, which would have eliminated thermal air currents.
Six months later, early 2015, Paul March from Eagleworks made new results public, claiming positive experimental force measurements with a torsional pendulum in a hard vacuum: about 50 µN with 50 W of input power at 5.0×10^−6 torr, and new null-thrust tests. The new RF power amplifiers were said to be made for hard vacuum, but still fail rapidly due to internal corona discharges, with not enough funding to replace or upgrade them, so measurements are still scarce and need improvement before a new report can be published.
Glenn Research Center offered to replicate the experiment in a hard vacuum if Eagleworks manages to reach 100 µN of thrust, because the GRC thrust stand cannot measure forces lower than 50 µN.
Eagleworks later announced a plan to upgrade their equipment to higher power levels, use vacuum-capable RF amplifiers with power ranges of up to 125 W, and to design a new tapered cavity analytically determined to be in the 0.1 N/kW range. The test article will be subjected to independent verification and validation at Glenn Research Center, the Jet Propulsion Laboratory, and the Johns Hopkins University Applied Physics Laboratory
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Reposted via Next Big Future
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