How the EmDrive works: Inventor of revolutionary 'Star Trek' space thruster reveals all

A controversial space propulsion device that could speed up space travel is currently setting the world alight – though a large number of scientists argue that it is complete nonsense, the technology also has a huge number of fans on the internet who want to see it succeed.

But how exactly does British engineer Roger Shawyer's EmDrive work? Simply put, the EmDrive is a microwave thruster that aims to replace the rocket engines of today (for a more in-depth explanation, see What is the EmDrive and why should I care?).

Conventional rocket engines require some sort of propellant in order to make them move forward, so fuel like liquid oxygen and kerosene are burned in the engine, and the reaction causes the rocket to be propelled forwards, while flames come out of the back of the thruster.

What makes the EmDrive different is that it requires no propellant at all. Electricity is applied to the thruster and converted into microwaves. The microwave photons are then fired into the thruster's truncated cone-shaped closed metal cavity, and the microwave photons push against the large end of the cone, causing the small end to accelerate in the opposite direction.

Some academics argue that the EmDrive cannot possibly work because according to the law of conservation of momentum, in order for a thruster to gain speed in one direction, a propellant must be expelled in the opposite one, and since the EmDrive is a closed system with no propellant, it violates our understanding of physics.

However, other scientists that have attempted to replicate Shawyer's work and build their own versions of the EmDrive have found that the device does produce thrust, even though they do not know why.

Dr Martin Tajmar, Professor and Chair for Space Systems at the Dresden University of Technology's Institute of Aerospace Engineering, renowned for his work in researching and debunking space propulsion systems, was able to detect levels of thrust in his experiments, and in December, the American Institute of Aeronautics and Astronautics (AIAA) will be publishing a peer-reviewed paper on the EmDrive by Nasa Eagleworks.

The race is now on to see who will be the first to commercialise the EmDrive technology and potentially speed up time travel, as well as making it much cheaper to launch satellites into space.

The UK Ministry of Defence and the Pentagon are apparently interested in the EmDrive for spy satellites, and US chemical engineer Guido Fetta, who has been promoting a rival technology to the EmDrive called the Cannae Drive since 2011, is now hoping to beat Shawyer and everyone else to commercialising the technology by launching it on a cubesat into orbit to prove it works.