Nasa has been investigating the drive along

It has been dubbed the 'impossible engine', that could take humans to Mars in just 10 weeks - but nobody knows how.

The so-called EmDrive creates thrust by bouncing microwaves around in an enclosed chamber, and uses only solar power.

Many argue the concept is simply hype, suggesting the design goes against the laws of physics , and now a Nasa lab that has been studying the concept is set to publish its findings for the first time it has been claimed.

Scroll down for video

A prototype of the 'impossible' fuel-free engine that some say power a spacecraft to Mars in just 10 weeks. The design is now set to undergo peer-review. Many maintain the system goes against the laws of physics

WHAT IS AN EM DRIVE? The concept of an EmDrive engine is relatively simple. It provides thrust to a spacecraft by bouncing microwaves around in a closed container. Solar energy provides the electricity to power the microwaves, which means that no propellant is needed. The implications for this could be huge. For instance, current satellites could be half the size they are today without the need to carry fuel. Humans could also travel further into space, generating their own propulsion on the way. But when the concept was first proposed it was considered implausible because it went against the laws of physics. Its allegedly fuel-free nature also means that the drive may directly contradict the law of conservation of momentum. It suggests it would produce a forward-facing force without an equal and opposite force acting in the other direction. Advertisement

The idea for an EmDrive was proposed in 2000 by a researcher named Roger Shawyer.

Since then four independent labs, including one at Nasa, have recreated the drive.

But the mysterious engine had baffled scientists because it appeared to violate the law of conservation of momentum, which states for every action there has to be an equal and opposite reaction.

This means the rocket can only accelerate forward if a force of equal magnitude is sent in the other direction - the rocket's exhaust.

Nasa's Eagleworks team is now ready to reveal its findings, it has been claimed - sending the physic world into a tizzy.

'It is my understanding that Eaglework's new paper has been today accepted for publication in a peer-review journal, where it will be published,' claims one user on the Nasa Spaceflight forum.

Earlier this year, an employee confirmed the team was working on the paper.

'The Eagleworks Lab is NOT dead and we continue down the path set by our NASA management.

'Past that I can't say more other than to listen to Dr Rodal on this topic, and please have patience about when our next EW paper is going to be published. Peer reviews are glacially slow,' Eagleworks engineer Paul March wrote on the same forum.

Earlier this year, a paper published in AIP Advances suggests the EmDrive produces an exhaust like every other rocket.

Simulated transverse magnetic modes TM20, (red high, blue low) at the wide and narrow ends of the EmDrive tapered cavity differ from each other. This implies interference of microwaves, and hence also anisotropic efflux of paired photons. The loss of momentum results in an equal and opposite reaction, i.e., thrust.

'EmDrive works just like any other engine,' Dr Arto Annila, physics professor at the University of Helsinki and lead author of the paper, told MailOnline.

'Its fuel is the input photons at microwave lengths.'

The researchers suggest the photons coming out of the machine interfere with each other, so that the overall effect seems as if nothing is there.

'In the cavity the input photons will bounce back and forth, and invariably some of them will interfere completely destructively.'

The technology has been dubbed the 'warp drive' for its similarity to the power plant from the fictional Star trek series.

'Then the two photons will be exactly 180 degrees out phase.

'At the complete interference electromagnetic fields for the two photons will cancel exactly, but the photons themselves continue to propagate.'

The idea is the same as water waves travelling together, at the exact right time so that the crest of one wave is exactly at the trough of the other and cancelling each other out.

The water does not go away, it's still there. In the same way the pairs of photons are still there and carrying momentum even though they cannot be seen as light.

The Nasa Eagleworks team is tasked with investigating radical propulsion methods

The idea is the same as water waves travelling together, at the exact right time so that the crest of one wave is exactly at the trough of the other

'The paired photons without net electromagnetic field will escape from the cavity,' Dr Annila said. 'This efflux of paired photons is the exhaust of EmDrive.'

'When the cavity is asymmetric, like the tapered cone, the efflux of paired photons is also asymmetric. Therefore the loss of momentum carried by the paired photons is uneven. In other words, thrust is non-zero.'

Dr Annila came up with the idea along with Dr Erkki Kolehmainen, an organic chemistry professor at the University of Jyväskylä and Patrick Grahn, a multiphysicist at engineering software firm Comsol.

'Thrust without exhaust is of course impossible,' the authors wrote in their. 'Yet, certain resonant cavities, when fueled with microwaves, deliver thrust without apparent exhaust.'

Their theory suggest the exhaust produced by the EmDrive is there, but just cannot be seen.

Dr Annila said the photons could theoretically be detected by an interferometer, the same instrument used to detect gravitational waves.

'My gut feeling is that it will be very difficult to detect such a small excess in energy density, especially when operating EmDrive steadily,' he said.

'Namely changes are more amenable to detection in any case. But still our idea about the exhaust can be useful to design the cavity for pairing photons better for an exit in a preferred direction, and hence to generate more thrust.'

HOW THE EMDRIVE PRODUCES THRUST WITHOUT AN EXTERNAL FORCE Dr Mike McCulloch of Plymouth University has a new explanation about how the EmDrive works The EmDrive creates thrust by bouncing microwaves around in an enclosed chamber, and uses only solar power. According to classical physics, the EM Drive should be impossible because it seems to violate the law of conservation of momentum. The law states that the momentum of a system is constant if there are no external forces acting on the system – which is why propellant is required in traditional rockets. But Mike McCulloch of Plymouth University came up with a possible explanation based on a new theory of inertia. McCulloch's suggests inertia arises from an effect predicted by Einstein's theory of general relativity called 'Unruh radiation'. The Unruh radiation effect states that if you're accelerating in a vacuum, empty space will contain a gas of particles at a temperature proportional to the acceleration. According to McCulloch, inertia is the pressure that the Unruh radiation exerts on an accelerating body. When the accelerations involved are smaller, such as is the case with the EmDrive, the wavelength of Unruh radiation gets larger. At extremely small accelerations, the wavelengths become too large to fit in the observable universe. As a result, inertia may only take on whole-wavelength units over time, causing it to become 'quantized.' This means it can only in some multiple of a unit of measure, causing sudden jumps in acceleration. But because of the EmDrive's truncated cone, the Unruh radiation in tiny. The cone allows Unruh radiation of a certain size at the large end but only a smaller wavelength at the other end, according to an in-depth report by MIT. This means the inertia of photons inside the cavity change as they bounce back and forth. To conserve momentum, they are forced to generate thrust. The concept of an EM Drive engine is relatively simple. It provides thrust to a spacecraft by bouncing microwaves around in a closed container. Dr Mike McCulloch, a scientist at Plymouth University, says something known as 'Unruh radiation' may be behind the bizarre performance of drive Advertisement



