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NASA Tests Microwave Space Drive
schwit1 (797399) writes with news that NASA scientists have tested the EmDrive, which claims to use quantum vacuum plasma for propulsion. Theoretically improbable, but perhaps possible after all. If it does work, it would eliminate the need for expendable fuel (just add electricity). From the article:Either the results are completely wrong, or NASA has confirmed a major breakthrough in space propulsion. A working microwave thruster would radically cut the cost of satellites and space stations and extend their working life, drive deep-space missions, and take astronauts to Mars in weeks rather than months. ... [According to the researchers] "Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma."
Skepticism is certainly warranted: NASA researchers were only able to produce about 1/1000th of the force the Chinese researchers reported. But they were careful to avoid false sensor readings, so something is going on. The paper declined to comment on what that could be, leaving the physics of the system an open problem.
Let's stick to the important consequences. When will this reach KSP? Is a patch/hotfix in development?
Skepticism is certainly warranted: NASA researchers were only able to produce about 1/1000th of the force the Chinese researchers reported. But they were careful to avoid false sensor readings, so something is going on. The paper declined to comment on what that could be, leaving the physics of the system an open problem.
The physics of the system has two explanations, one relativistic relying on a classical radiation pressure, and one quantum relying on virtual particles, and is not an "open problem". These are things that were designed, not things that just work but we can't explain why. The EmDrive site will give you the relativistic model; the paywalled Chinese article presumably gives the quantum model. The NASA researchers produced 1/1000th of the force of the Chinese & English drives because they used a different design, which reduces the Q factor of the waveguide - again, this is explained on the EmDrive site. Now Chinese, English and American teams have all measured "anomalous" thrusts from this type of device, so skepticism is not really warranted on that basis, nor on the basis of a presumed anomaly in thrust magnitude when in fact that's all well understood.
Actually, it's infinitely improbable, therefore finitely probable. All they need is a heart of gold.
Don't be deceived by vacuum chamber: the device was placed inside a chamber designed to be evacuated, but the experiments were conducted at atmospheric pressure. Ionization effects of air were not considered, and to demonstrate force at pressure and not in vacuum does nothing to establish the utility of such apparatus for extra-atmospheric purposes.
In terms of thermonuclear fuel supply in the Sun, it's a good approximation. We're talking about space here.
It is possible to generate electricity without expendable fuel, whereas our current methods of chemical propulsion *must* use expendable fuel. Unless your religion doesn't believe in solar panels?
The best part of science is when we expect X to happen, but we get Y instead. And the very best of that is when X = nothing.
No. The NASA team have found unexplained faults in their test apparatus. The null experiment ALSO produced the tiny thrust.
Why won't you let me have my magic space drive? Picard had one. Solo had one. Why can't I have one?
Fact 1: The NASA team has measured approximately 30-50 micronewtons of thrust in the experiment
Fact 2: The NASA team experienced a similar thrust on a test item that was NOT design to experience any force.
It is pretty obvious that there was a systematic error in NASA's experiment.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
Compared to burning fossil fuels, electricity is easier to derive from multiple sources (solar panels, thermocoupled radioactive decay nuclear batteries, fuel cells), especially on a vehicle where refueling can be prohibitive.
For satellites, this is profound, as the life span of most satellites is determined by the amount of fuel they carry to correct orbital trajectories. Any time a satellite has to change orbit (i.e., retasked), it shortens it's service time significantly. Now, with reactionless propulsion, satellites are only limited by their ability to produce electricity. Of course, only when this technology proves out and it is able to be put into service.
For a Mars mission, for instance, it's a lot easier if all you need for propulsion is a fission reactor core and require no reactive fuel. Previously, you had to factor in this additional mass requirement. Now, all you have to worry about is breathable air and water for the crew.
Imagine a nuclear 747.
I'm already working on my pitch to Syfy.
SJW's don't eliminate discrimination. They just expropriate it for themselves.
Luckily, there are existing electric propulsion technologies. They don't provide much thrust, but they're extraordinarily efficient (they require so little "fuel" as to effectively not be using any, with VASIMR producing roughly 10x-20x the fuel efficiency of chemical rockets, and the current VASIMR engine is very inefficient in terms of heat loss and such). The problem is that we've never had any large source of power in space, so while electric propulsion is great for getting your probe around the solar system with a minimum of fuel consumption, or perhaps automated cargo runs to some future colony that isn't time sensitive, they're not going to get you anywhere.
However, if you fit a nuclear reactor inside a 747, strap a bunch of if VASIMR thrusters to it, then that'd actually work. You wouldn't get much thrust, though... the 200 kW VASIMR engine produces only 5N of thrust. If you put a nuclear reactor on the thing similar to what you'd find in a submarine, you'd get 300N of thrust. Compare that to the "Draco" rockets used by a SpaceX dragon as manoeuvring thrusters... they have 400N of thrust.
You're right. "Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)." Also: "within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure" I think maybe they made one of these: https://www.youtube.com/watch?...
Imagine a nuclear 747.
OK
Have gnu, will travel.
No, the question is how fast can it accelerate the average potato. NASA reported 30-50 mN of thrust., call it 40. The average potato is about 375 grams, call is 400 even so math is real east. F=m*a or a = F / M or 1e-7 m/sec^2.
40 mN is 0.04N
400g is 0.4kg
a = F/m = 0.04 / 0.4 = 0.1 m/s^2 not 0.0000001 m/s^2.
Therefore accelerating for 3e7 seconds (one year) results in a velocity of 3000 km/s. About 1% of lightspeed. And a distance of 330AU. You'll hit one lightyear in 19 years. Two lightyears in about 28 years, if you turn your potato around to decelerate, you'll deliver your potato to Alpha Century in 56 years. If you want to cook your potato by skimming one of the stars, it'll only take 38 years.
Science is all about firing a drunk pig out of a cannon just to see what happens.
Aside from the warp drive, which is currently from a physics stand point pure gobbledygook, the sub-luminal "impulse drive" of the Enterprise was a classical nuclear fusion plasma engine fueled by interstellar hydrogen gas (that's why those red things on the front of the Enterprise's warp drive nacelles were called Bussard collectors). It is technologically speaking far in excess of what we can do today, but nonetheless theoretically permitted by known laws of physics.
The Wired article speaks of Shawyer's EMDrive, which has been around for some time, and at first appears to confuse the EMDrive with a different technology Dr. Harold "Sonny" White of NASA has been working on for some time.
The tech report clears things up a bit. The test results are showing anomalous thrust, however NASA is reticent to attribute the thrust to Shawyer's theory of how it operates, which would violate conservation of momentum (hence the "impossible" in the title.
What the technical report says is something far more interesting. Dr. White has been working with several different test articles which use electromagnetic forces to increase the rate of virtual particle pair production in the quantum vacuum, then using the virtual particles during their very short time of existence as reaction mass. In other words, it is a reaction drive, but instead of carrying reaction mass in the tank, the investigators are trying to use mass borrowed from quantum vacuum plasma to generate a small, but measurable, amount of thrust.
The final sentence of the technical report contains the salient material:
"Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma. Future test plans include independent verification and validation at other test facilities."
Coypu
which is currently from a physics stand point pure gobbledygook
Dr. Alcubierre would beg to differ.
http://en.wikipedia.org/wiki/A...
The warp drive in Star Trek was based an earlier incarnation of this theory, which is based on results from Einstein. Warp drive FTL travel might not be possible, but the idea is definitely not "pure gobbledygook".
You are in a maze of twisty little passages, all alike.
Still wrong. VASIMR ejects ionized particles--mass--which is the same problem as a chemical rocket: eventually you run out of shit to eject.
We're looking for a technology that can take energy and turn it into movement without ejecting any mass. In other words: We're looking to keep going even when we have no mass to eject. You can't eject the control units, the ship's body, its atmosphere, or its crew, if you want it to keep functioning or support life; so your nuclear pile might remain hot longer than your mass resources hold out.
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It's probably #2. The paper, as presented at the 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, is available for purchase. I happened to have a spare $25 and a burning curiosity. The full paper isn't available on the NASA site, only the abstract can be gotten there for free. If you wanna read the details, you have to pay for 'em.
Anyhow, here's the relevant bit from the paper: "Two roughing pumps provide the vacuum required to lower the environment to approximately 10 Torr in less than 30 minutes. Then, two high-speed turbo pumps are used to complete the evacuation to 5x10E-6 Torr, which requires a few additional days. During this final evacuation, a large strip heater (mounted around most of the circumference of the cylindrical chamber) is used to heat the chamber interior sufficiently to emancipate volatile substances that typically coat the chamber interior walls whenever the chamber is at ambient pressure with the chamber door open. During test run data takes at vacuum, the turbo pumps continue to run to maintain the hard vacuum environment."
I'm not a physicist, but the paper is still an absolutely fascinating read, and contains a number of color photos of the test apparatus, the device itself, etc. The amount of detail they went into for the experiment is really impressive; seismically isolating the test chamber, using liquid metal (galinstan) electrical contacts to eliminate any forces due to a mechanical coupling to a wire, compensating for the magnetic field that is created by passing electricity through the device, and so on. This is NASA we're talking about here, the guys that do ROCKET SCIENCE. The idea that they wouldn't test this device in a vacuum is laughable.
Something spooky is going on inside this device, and I hope it doesn't take us too long to figure out what is really happening.
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