![star-trek-enterprise-uses-warp-drive[1].jpg](https://tmmacattach.nyc3.digitaloceanspaces.com/data/attachments/2/2859-d6ca101f763183f2041884ad51cf7d54.jpg "star-trek-enterprise-uses-warp-drive[1].jpg")
Every so often an article gets posted here about the state of these devices. These often end up being quite heated arguments between groups of people (on all sides) that are working with partial information, are conflating speculation with what we know, and that misunderstand what scientists are actually looking at.
So, because this will continue to be a hot topic, and because Eagleworks will be conducting more experiments in full vacuums soon, I wanted to collect what information has actually been revealed, not what has been speculated in sensationalist articles, echo chambers, and comment sections.
Let me be clear, although I described the news articles as sensationalist, the facts as we currently know them are ALSO quite sensational.
EmDrive vs. Cannae Drive
The EmDrive and the Cannae Drive are two different things. They were independently invented by two people. The EmDrive was invented by Roger J. Shawyer, a British aerospace engineer who has a background in defense work as well as experience as a consultant on the Galileo project (a European version of the GPS system).
The Cannae Drive was invented by Guido P. Fetta and was formerly known as the Q-Drive.
They both are claimed to use a specially shaped cavity, with constricted openings, and operate by using some form of electromagnetic radiation in the microwave spectrum to generate a directional force. The EmDrive is claimed to receive its force from the shape of the cavity and the shape of the opening, while the Cannae drive was claimed to receive its force from the shape of the cavity, opening, and from specially shaped "slots" on the inside of the cavity.
The EmDrive has been tested in a laboratory twice independently (once by a team at the China Northwestern Polytechnical University (NWPU) in Xi'an, and once by Eagleworks at the Johnson Space Center), under different conditions and setups, while the Cannae Drive has only been independently tested once by Eagleworks.
Although they are independently invented, and different in shape, and the inventors claim different effects are the cause of the resulting force, because of their similarities in concept and mode of operation, as well as the particular method of interacting with the microwaves, it is likely that if they work they operate on the same principle regardless of what the inventors claim.
The Inventors Claims
Both inventors claim that their devices do not actually violate any physics, and instead take advantage of very particular but speculative aspects of existing physics. It is important to note that while both theories are being tested, Eagleworks is testing whether or not the devices work as a SEPARATE thing from why they work.
Shawyer claims that the EmDrive works only on radiation pressure. Light is both wave-like and particle-like. Though it has no mass, it does have momentum, and the fact that light exerts a very small force on the objects it interacts with is well documented.
Shawyer claims that the pressure exerted by light is a result of the group velocity of the wave, not the singular velocity of the the photon that interacts. He then uses this to contend that radiation pressure is actually a Lorentz force. As scientists understand it now, the momentum of a photon is related to phase velocity, while group velocity measures the propagation of information.
Fetta contends that the Cannae Drive creates a bias in the quantum vacuum and pushes against it. Basically, physicists think that at very, very small scales, much smaller than atoms or even protons, space bubbles with quantum fluctuations. This bubbling is represented in the math as sort of imaginary particles that are spawned in pairs, and then very, very quickly the pairs come back together and destroy each other. Fetta contends that the Cannae Drive creates a bias where some of these particles never come back together, and then "pushes" against them.
Cannae Tests So Far
The only independent (not conducted by the inventor, the inventor's company, or by labs hired by the inventor) tests of the Cannae Drive that I can verify have been done by Eagleworks at the Johnson Space Center.
They performed three tests:
- The device as the inventor designed it.
- The device as the inventor designed it without the slotting that the inventor claimed was critical. (Called the "null test".)
- A control test that used the same energy, but without the cavity present in the design.
The results of these tests were as follows:
- Approximately 25 micronewtons of thrust at 50 Watts.
- The same results as test #1, showing that at the very least, the slotting provided no benefit or detriment to the effect happening.
- No measurable thrust.
For each of these tests they use a torsion pendulum which could measure thrust down to about 10 micronewtons or so. They also ran the test multiple times. In addition, they ran the test in two directions, making sure that the directional thrust changed with the direction of the device (to attempt to eliminate the possibility of noise or instrumentation error). The Cannae Drive passed these test, and the control test showed it was unlikely (although not impossible) to be a heating or air current effect.
The confusion over the naming of the "null test" however led many people to think that NASA reported the same thrust in the control test. This was not the case. The fact that the null test showed only that the inventor's ideas for why thrust was being measured were incomplete or wrong, but it is certain that thrust was measured. That still does not eliminate other factors in measurement or the test setup that might have accounted for the measured thrust, although the control test does make the list smaller.
The "null test" also was only performed on the Cannae Drive, and has no bearing on the EmDrive tests, as the EmDrive has no such features which might have be tested in this way, which has been another point of confusion among many people.
EmDrive Tests
The following independent tests have been performed for the EmDrive.
- A test at 2500 W of power during which a thrust of 750 millinewtons was measured by a Chinese team at the Chinese Northwestern Polytechnical University.
- A test at 50 W of power during which a thrust of 50 micronewtons was measured by Eagleworks at the Johnson Space Center at ~760 Torr of pressure. (Summer 2014)
- A test at 50 W of power during which a thrust of 50 micronewtons was measured by Eagleworks at the Johnson Space Center at ~5.0×10−6 torr or pressure. (Early 2015)
- A test at 50 W of power during which an interferometer (a modified Michelson device) was used to measure the stretching and compressing of spacetime within the device, which produced initial results that were consistent with an Alcubierre drive fluctuation.
All these tests were conducted with a control device that did not produce thrust.
UPDATED
NOTE: a better source was found for the Chinese results, and I have changed this section to reflect that.
Test #1 was conducted at the direction of lead researcher Juan Yang. She tested the device at several power levels and frequencies using the same equipment used to test Ion Drives. The given result above was the largest result produced. Her team estimated that the total measurement error was less than 12%. Source 1[1] | Source 2[2]
Tests number 2 and 3 were performed multiple times, changing direction of the device and observing a corresponding change in the direction of force. They were not especially careful about controlling for ALL variables however, mostly owing to the lack of funding for the project. The positive tests have resulted in more funding becoming available, although it is still very, very little, and possibly not enough to explain where the error occurred if the measurement is error of some kind.
Test #4 was performed, essentially, on a whim by the research team as they were bouncing ideas off each other, and was entirely unexpected. They are extremely hesitant to draw any conclusions based on test #4, although they certainly found it interesting.
The Eagleworks team has been able to dedicate very little hardware towards this experiment, as there has been almost no dedicated funding for this experiment. The lack of funding is related to how outlandish the claims are to those who understand physics very well, and the lack of adequate explanation on the math behind the devices from the inventors.
Continued at: The FACTS as we currently know them about the EmDrive and Cannae Drive : Futurology
More info at: New Test Suggests NASA's "Impossible" EM Drive Will Work In Space
More technical info at: Evaluating NASA’s Futuristic EM Drive | NASASpaceFlight.com
Please turn out to be a warp drive! Please turn out to be a warp drive! Please turn out to be a warp drive! Please turn out to be a warp drive! Please turn out to be a warp drive! Please turn out to be a warp drive!
