Engineer Roger Shawyer’s controversial EmDrive thruster jets back into relevancy this week, as a team of researchers at NASA’s Eagleworks Laboratories recently completed yet another round of testing on the seemingly impossible tech. Though no official peer-reviewed lab paper has been published yet, and NASA institutes strict press release restrictions on the Eagleworks lab these days, engineer Paul March took to the NASA Spaceflight forum to explain the group’s findings. In essence, by utilizing an improved experimental procedure, the team managed to mitigate some of the errors from prior tests — yet still found signals of unexplained thrust.
Isaac Newton should be sweating.
Flying in the face of traditional laws of physics, the EmDrive makes use of a magnetron and microwaves to create a propellant-less propulsion system. By pushing microwaves into a closed, truncated cone and back towards the small end of said cone, the drive creates the momentum and force necessary to propel a craft forward. Because the system is a reaction-less drive, it goes against humankind’s fundamental comprehension of physics, hence its controversial nature.
On the NASA spaceflight forums, March revealed as much as he could about the advancements that have been made with EmDrive and its relative technology. After apologizing for not having the ability to share pictures or the supporting data from a peer-reviewed lab paper, he starts by explaining (as straightforward as rocket science can get) that the Eagleworks lab successfully built and installed a 2nd generation magnetic damper which helps reduce stray magnetic fields in a vacuum chamber. The addition reduced magnetic fields by an order of magnitude inside the chamber, and also decreased Lorentz force interactions.
However, despite ruling out Lorentz forces almost entirely, March still reported a contamination caused by thermal expansion. Unfortunately, this reported contamination proves even worse in a vacuum (i.e. outer space) due in large part to its inherently high level of insulation. To combat this, March acknowledged the team is now developing an advanced analytics tool to assist in the separation of the contamination, as well as an integrated test which aims to alleviate thermally induced errors altogether.
While these advancements and additions are no doubt a boon for continued research of the EmDrive, the fact that the machine still produced what March calls “anomalous thrust signals” is by far the test’s single biggest discovery. The reason why this thrust exists still confounds even the brightest rocket scientists in the world, but the recurring phenomenon of direction-based momentum does make the EmDrive appear less a combination of errors and more like a legitimate answer to interstellar travel.
Eagleworks Laboratories’ recent successful testing is the latest in a long line of scientific research allowing EmDrive to slowly shed its “ridiculous” title. Though Shawyer unveiled the device in 2003, it wasn’t until 2009 that a group of Chinese scientists confirmed what he initially asserted to be true — that is, that filling a closed, conical container with resonating microwaves does, in fact, generate a modest amount of thrust towards the wide end of the container. Although extremely cautious about the test, the team in China found the theoretical basis to be correct and that net thrust is plausible.
The thing is, the initial reaction on this theory (especially from the west) was met with polite skepticism. Though the published work showed the calculations to be consistent with theoretical calculations, the test was conducted at such low power that the results were widely deemed to be useless. Luckily, this didn’t stop the good folks over at NASA from giving the EmDrive a spin, resulting in an official study that was conducted in August of 2013. After deliberating on the findings, the space agency officially published its judgment in June of the following year before presenting it at the 50th Joint Propulsion Conference in Cleveland, Ohio.
NASA concluded the RF resonant cavity thruster design does produce thrust “not attributable to any classical electromagnetic phenomenon.” In other words, NASA confirmed Shawyer’s initial prognosis (much like the team of Chinese scientists), but couldn’t come up with a reasonable explanation as to why the thing works outside of, “it just does.”
Moving forward, NASA’s short term objective is to conduct a diverse array of tests on a quantum vacuum plasma thruster (a similar propellantless engine flatter in shape than the EmDrive), in hopes of gaining independent verification and validation of the thruster. Initial IV&V testing will be supported by the Glenn Research Center in Cleveland, Ohio, making use of a stainless steel vacuum chamber which has the capacity to detect force at a single-digit micronewton level, called a low-thrust torsion pendulum.
After that, a similar round of low-thrust torsion pendulum tests will then be conducted at NASA’s Jet Propulsion Laboratory before comparing the findings. It’s also reported that the Johns Hopkins University Applied Physics Laboratory has contacted the lab about conducting Cavendish Balance-type testing of the IV&V shipset. Ideally, this test would allow Johns Hopkins to measure the amount of gravitational force exerted in propellantless engines.
At this time, it’s unknown when Eagleworks Laboratories intends to officially publish its peer-reviewed paper, but even so, just hearing of the EmDrive’s advancements from one of its top engineers bodes well for the future of this fascinating tech.
