One of the top engineers working on NASA’s controversial EM Drive thruster at the Eagleworks Laboratory at the Johnson Space Center in Texas has spoken publicly about the current state of the project. This is the first direct update in months, as NASA is keeping a very tight lid on the developments.

The latest news regarding the EM Drive, which produces a thrust seemingly from nowhere, comes from Paul March, one of the principal investigators on the EM Drive, and was published on the NASA Spaceflight forum. The post is in reply to an unpublished paper that claims the unaccounted thrust is generated by the Lorentz force between the EM Drive and the Earth’s magnetic field, something that March says his tests prove is not true.

“I will tell you that we first built and installed a 2nd generation, closed face magnetic damper that reduced the stray magnetic fields in the vacuum chamber by at least an order of magnitude and any Lorentz force interactions it could produce,” commented March in the post on October 28. “And yet the anomalous thrust signals remain...” he added.

March also claims that in the latest developments, thermal expansion of the thruster is taken into account to reduce all possible sources of error. But the anomalous thrust is still being observed, indicating a yet unexplained cause for it.

Once the tests at the Eagleworks Laboratory are complete, they will be subjected to independent verification and validation at the Glenn Research Centre, at the Johns Hopkins University Applied Physics Laboratory, and at the Jet Propulsion Laboratory.

The EM Drive thruster is a hypothetical thruster that uses no fuel. It uses a magnetron, a high-powered vacuum tube where the interaction between a magnetic field and electrons generates microwaves. The magnetron sends the microwaves into a truncated cone, hitting the short end and, according to the proponents of this technology, generating thrust.

The EM Drive is controversial because it violates Newton’s conservation of momentum laws. The EM Drive doesn’t apply any known force on the smaller end of its cone, so the thruster should not move.

The supposed thrust is small, on the order of the micronewton (the weight of a mosquito on Earth), so unaccounted phenomena could be mimicking thrust. Such a small force might not seem useful for space travel, but it would be significant when scaled up in a spacecraft. If the EM Drive becomes a reality, some say it could be used to reach the edge of the Solar System in months not decades.