As a follow-up to a story we reported on last month, the leaked research paper on the controversial EM Drive that NASA was reportedly set to present for peer review has been published, in the American Institute of Aeronautics and Astronautics’ (AIAA) Journal of Propulsion and Power. The submission of this document is an important development: NASA’s Eagleworks Laboratories would not publish data such as this if they were not confident that this propellantless engine actually works.

The EM Drive, first devised by engineer Roger Shawyer in 2001, purportedly produces thrust without having to expel a reactant — an effect that would violate Newton’s Third Law, according to the device’s critics. The cone-shaped device makes use of microwaves that rebound inside the chamber, producing what is theorized to be an internal asymmetry field that produces its thrust.

The drive’s sole source of power is electricity, meaning that the device would not only be able to produce continuous thrust, but a vehicle equipped with engines such as this also wouldn’t have to carry bulky propellant to expend. With the exception of ion engines, current rocket motors expend all of their fuel within a matter of minutes, meaning that their acceleration is extremely short lived, and even ion engines still need to carry heavy reactant to produce thrust.

While NASA’s experiments have eliminated many of the potential mundane sources that might be causing the thrust that is being observed, further testing will be needed to see if the EM Drive is actually viable for use on spacecraft. Toward that end, researchers are planning on launching a shoebox-sized CubeSat-based drive into orbit, an acid test to see if the drive actually works in the vacuum of space.