Tag: Shawyer

A piece of Star Trek type technology appears to be closer to becoming reality, with the EMdrive mechanism now proven independently: Nasa validates ‘impossible’ space drive (wired.co.uk, July 2014)

British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems, but critics reject his relativity-based theory and insist that, according to the law of conservation of momentum, it cannot work.

The NASA paper (PDF) Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum avoids conjecturing on how the system works, instead focusing on the test methodology that validates the observations.

So while the “why it works” is not clear yet, scientists are becoming more interested as there really appears to be something going on – a paper (PDF) on the possible workings of it behind it Can the Emdrive Be Explained by Quantised Inertia? (Michael E. McCulloch, University of Plymouth) was published in Progress in Physics, January 2015:

It has been shown that cone-shaped cavities with microwaves resonating within them move slightly towards their narrow ends (the emdrive). There is no accepted explanation for this. Here it is shown that this effect can be predicted by assuming that the inertial mass of the photons in the cavity is caused by Unruh radiation whose wavelengths must fit exactly within the cavity, using a theory already applied with some success to astrophysical anomalies where the cavity is the Hubble volume. For the emdrive this means that more Unruh waves are “allowed” at the wide end, leading to a greater inertial mass for the photons there. The gain of inertia of the photons when they move from the narrow to the wide end, and the conservation of momentum, predicts that the cavity must then move towards the narrow end, as observed. This mode l predicts the available observations quite well, although the observational uncertainties are not well known.

See also Mike McCullogh’s blog post MiHsC vs EmDrive: paper link.

Wikipedia’s entry on the EMdrive contains another overview of the differing thoughts on this topic, and numerous references.