EMdrive inventor Shawyer’s latest information on military applications and superconducting EMDrive progress

Roger Shawyer, SPR Ltd, invented the EMdrive and recently gave an EMdrive presentation to the UK Defence Academy Shrivenham.

EmDrive is the first true Propellantless Propulsion technology.
High frequency electrical energy is directly converted to thrust.
It is a resonant microwave cavity, shaped to obtain different group velocities at each end, and thus achieve a force difference as the EM wave reflects off each end plate.

EmDrive is not a reactionless thruster, it is simply a new class of electrical machine.

Conventional microwave technology limits the maximum Q of resonators to around 50,000, giving a specific thrust of 200 mN/kW at 3 km/s. This technology will be utilised in first generation engines where typical applications will be the orbital transfer and orbit maintenance of communication satellites and the primary propulsion for science missions.

Classic Physics can answer all questions about EmDrive
How is Momentum Conserved? EmDrive obeys Newton’s Laws
How is force produced? Radiation Pressure. Maxwell.
Why are the end plate forces different? Different group velocities due to different diameters. Cullen 1952
How is the force multiplied? EmDrive is a Resonant cavity with a multiplication factor Q. Bailey 1955
Why is EmDrive an Open System? Einstein’s theory of Special Relativity
Why are there no side wall forces? Thrust due to travelling waves not standing waves.
How is energy conserved? EmDrive is an electrical machine.
What limits thrust in high Q thrusters? Internal Doppler shift.
How is thrust calculated? Thrust equation.
How is thrust measured? With great care.

If the science is sound why is it not universally accepted?

EmDrive theory requires the convergence of a number of basic laws of Physics in an unfamiliar way.

Understanding the theory requires knowledge, patience and the ability to do the maths.

“Extraordinary claims require extraordinary evidence”
EmDrive is a difficult technology to design, build, test and thus difficult to prove to exacting standards.
Design requires special software
Build requires precision engineering
Test requires expensive test equipment and sophisticated facilities. (e.g. NWPU)

EmDrive thrusters giving significant thrust(100s mN) are potentially lethal.
Magnetron or TWTAs require High voltage power supplies
High Q, high power thrusters store significant energy levels.
High power microwaves cause blindness and can kill.

Proof of EmDrive theory and operation takes time, money and intellectual effort, which requires significant funding.
It is much easier to limit funding and criticise the level of experimental proof.

In Dec, 2016 an image appeared on the internet illustrating how an 8GHz EmDrive thruster would fit into a modern, off-the-shelf, 3 unit Cubesat.

Shawyer claims that any country with LEO capability will be able to deploy low cost orbital mines to GEO.

Superconducting EMDrive work

Any analysis of missions incorporating microwave engines will need to take into account the second important equation. This equation results from consideration of the principle of the conservation of energy and introduces the concept of the loaded Q of the engine. The Q of any resonant circuit can be defined as the stored energy divided by the energy loss per cycle. Thus as soon as kinetic energy is extracted from the engine, the stored energy, and hence the Q, falls.

A second generation engine using similar technology would however be subject to equation 2, and the effect at these high values of unloaded Q is dramatic. An average velocity of only 0.1 m/sec will reduce the specific thrust to 0.93 Tonne / kW. Equation 2 therefore constrains the applications of second generation engines to those where the kinetic energy output is limited.

We have defined the maximum Q of the engine, under static thrust conditions as Qu, the unloaded Q. Under acceleration, the Q of the engine at an average velocity of is defined as Ql, the loaded Q.

In orbit testing of EmDrive has been reported by CAST, suggesting commercial use of EmDrive has now been authorised by China

Implies military applications of first generation technology are now operational. Western space assets vulnerable.

January 2014. Information from US (AIM) and China (NWPU) reveal they both have a detailed knowledge of EmDrive theory, and a solution to the High Q Acceleration Problem.

Further work at SPR Ltd has also solved High Q acceleration problem (3G design).

2015. Gilo Industries Research + SPR Ltd
New superconducting cavity design
YBCO thin film technology
LN2 and LH2 cooling

Supertanker Emdrive proposal

Batillus class supertanker 555,000 tonnes, 64,800 bhp
Approximate thrust 648 tonnes, (100bhp/tonne)
Conventional Electrical Specific Thrust = 0.13kN/kW(e)

2G 900MHz LH2 YBCO thruster gives estimated microwave specific thrust 10kN/kW(m)

Closed cycle cooling system (e.g. Turbo-Brayton type) efficiency 4%
Thus predicted 2G EmDrive Electrical Specific Thrust = 0.4kN/kW(e)
Use of LNG boil-off in a total loss cooling system would enable much higher specific thrust.

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