The 'impossible' fuel-free engine, which could take a humans to Mars in just 10 weeks, is still challenging science. When the idea was initially suggested, it was considered improbable as it went in contradiction with the laws of physics. But subsequent tests of the EM Drive have shown that the idea could revolutionize space travel. Now NASA has provided the first public update on the test in months, and it appears to propose that it does, in fact, work.
Researchers, though, still do not know why.
The update was given by Paul March, one of the top engineers employed on the EM Drive thruster at the Eagleworks Laboratory at the Johnson Space Center in Texas. He said NASA has achieved to remove some of the mistakes from former tests - but still discovered signals of mysterious thrust. March's announcement is the first direct announcement in months, with the space agency mostly remaining silent about any developments on the notorious project.
March posted on the NASA Spaceflight forum in reply to an unpublished paper that claims the unaccounted thrust is produced by something known as the Lorentz force. The Lorentz force is the force that is applied by a magnetic field on a moving electric charge.
But March says his tests prove this is not true.
'I will tell you that we first built and installed a second generation, closed face magnetic damper that decreased the stray magnetic fields in the vacuum chamber by at least an order of magnitude and any Lorentz force interactions it could generate,' he said. 'And yet the anomalous thrust signals remain.'
March also says that in the latest developments, thermal expansion of the thruster is taken into account to decrease all potential sources of error. Scientists say the new drive could carry passengers and their gear to the moon in as little as four hours. A trip to Alpha Centauri, which would take tens of thousands of years to reach right now, could be grasped in just 100 years. The system is based on electromagnetic drive, or EMDrive, which transforms electrical energy into thrust without the requirement for rocket fuel. While there has been some skepticism surrounding the EMDrive, in April NASA released outcomes of their own test which exhibited that the EMDrive did in fact produce thrust.
'Thrust measurements of the EMDrive challenge classical physics' anticipations that such a closed (microwave) cavity should be unusable for space propulsion as of the law of conservation of momentum,' announced NasaSpaceFlight.com in April The site has become an unofficial source of EMDrive news, with NASA engineers seemingly posting on its forum.
Tajmar wrote: 'Additional tests need to be performed to study the magnetic interaction of the power feeding lines used for the liquid metal contacts.'
'Nevertheless, we do observe thrusts close to the magnitude of the actual predictions after removing many potential error sources that should permit further investigation into the phenomena.
'Next steps include better magnetic shielding, further vacuum tests and improved EMDrive models with higher Q factors and electronics that permit tuning for optimal operation.'
According to classical physics, the EMDrive should be impossible because it appears to violate the law of conservation of momentum.
The law states that the momentum of a system is constant if there are no outside forces acting on the system – which is why propellant is compulsory in traditional rockets. Scientists from the US, UK and China have demonstrated EMDrives over the past few decades, but their fallouts have been controversial as no one has been precisely sure how it works.
Earlier this year, NASA built an EMDrive that works in circumstances like those in space, according to users on forum NasaSpaceFlight.com. A number of those discussing the plan on the technical forum claim to be NASA engineers who are involved in the project. The idea of an EmDrive engine is comparatively simple. It delivers 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 required. The implications for this could be huge. For instance, existing satellites could be half the size they are today without the requirement to carry fuel. Humans could also travel further into space, producing their own propulsion on the way. When London-based Roger Sawyer came up with idea in 2000, the only team that took him seriously was a group of Chinese researchers.
In 2009, the team allegedly created 720 millinewton (or 72g) of thrust, sufficient to build a satellite thruster. But still, nobody believed they had accomplished this. Last year, Pennsylvania-based researcher Guido Fetta and his team at NASA Eagleworks published a paper that proves that a same engine works on the same principles.
Their model, dubbed Cannae Drive, yields much less thrust at 30 to 50 micronewtons - less than a thousandth of the output of some comparatively low-powered ion thrusters used today. On the NasaSpaceFlight.com, those allegedly involved in the project claim that the reason former EmDrive models were criticized were that none of the tests had been carried out in a vacuum. Physics says particles in the quantum vacuum cannot be ionised, so therefore you cannot push against it. But NASA’s newest test is claimed to have shown otherwise.
NASA has effectively tested their EmDrive in a hard vacuum – the first time any organization has reported such a successful test,' the scientists wrote.
'To this end, NASA Eagleworks has now abolished the prevailing hypothesis that thrust measurements were due to thermal convection.'
However, NASA’s official site says that: 'There are many 'absurd' theories that have become truth over the years of scientific research.
'But for the near future, warp drive remains a dream,' in a post updated earlier this year.