Quote from: R.W. Keyes on 01/02/2018 03:44 pm...Expensive, but worth it. Can we start a cost-estimation?I do that for a living, and my group in NG builds some of the best cubesat hardware available. We can handle up to about 500W of power (continuous) and a projected reliability of >80% at 3 years in single systems or way better than that with redundancy (which we also support). That core HW, including flight software, launch costs, ground station support, and mission ops over a reasonable lifespan is on the order of $1M.How cheap CAN you get it? Probably <$100K but the projected reliability is in the trash can. Satellites in this cost range have a >50% likelihood to never be heard from once deployed and will never survive deep space radiation. Outside the Earth's magnetosphere, the radiation is HARSH.
...Expensive, but worth it. Can we start a cost-estimation?
Monomorphic built his shell on a 3-D printer, with a copper film interior. Would those kinds of thermoplastics (?) be able to be space rated?
FYI:Acta AstronauticaArticles in PressComments on theoretical foundation of “EM Drive”In Press, Accepted Manuscript, Available online 4 January 2018C.-W. Wu-------HighlightsThe theoretical derivation of the net thrust in “EM drive” is found to be inaccurate.Self-contradiction in physics is found in the concept of “EM drive”.The theoretical foundation of the “EM drive” is found to be not solid.
The concept of EM Drive has attracted much attention and groups of work have been conducted to prove or verify it, of which the published experimental outcome is criticized in great details while the theoretical foundation has not been discussed. The present essay investigates on the theoretical derivations of the net thrust in the “EM drive” and reveals the self-contradiction arising at the very start, when the law of conservation of momentum was utilized and opposed simultaneously.
So let's go back a couple of years in this thread and sum up: No one has proposed a complete explanation of the EM drive in a comprehensive manner that has garnered acceptance. Yet, of the results that have been published, there have been null and positive results, but replication has not been consistent. No results that I have seen rises so far above the noise floor to warrant a "Eureka" moment.Major governments, including China, "may" be conducting in space tests, but they're not going to tell because of the national security implications. On top of that are the folks who ARE doing experiments who are fairly quiet, maybe because of concerns on protecting future economic rights.Monomorphic, you're the one left that has been quite open and helpful but has not published a comprehensive set of results. So the Rebel Alliance of physicists and wannabe's wait."Help us Monomorphic, you're our only hope."
Mostly, I agree, though I continue to hold out hope that Shell will publish her research, and maybe a couple others. (Star Drive, maybe?)
Quote from: VAXHeadroom on 01/04/2018 10:55 pmQuote from: R.W. Keyes on 01/02/2018 03:44 pm...Expensive, but worth it. Can we start a cost-estimation?I do that for a living, and my group in NG builds some of the best cubesat hardware available. We can handle up to about 500W of power (continuous) and a projected reliability of >80% at 3 years in single systems or way better than that with redundancy (which we also support). That core HW, including flight software, launch costs, ground station support, and mission ops over a reasonable lifespan is on the order of $1M.How cheap CAN you get it? Probably <$100K but the projected reliability is in the trash can. Satellites in this cost range have a >50% likelihood to never be heard from once deployed and will never survive deep space radiation. Outside the Earth's magnetosphere, the radiation is HARSH.Monomorphic built his shell on a 3-D printer, with a copper film interior. Would those kinds of thermoplastics (?) be able to be space rated?
EM引擎出现已经快20年了,尚未进入实用阶段,说明这个技术很不靠谱。尽管如此,好多人都想自己动动手,制造一个emdrive。据说,,,能够制造出来具有推力的引擎,并且得到公认的人并不多。那么如何制造这样一个引擎呢?有人制造过,却未能测到推力。他说费用在数万元。。。各位大婶,,各位大神。。。你们有没有知道怎么自行制造一个emdrive。。有没有资料。求共享。。
ref: https://www.sciencedirect.com/science/article/pii/S0094576517317356Highlights are provided as follows:• The theoretical derivation of the net thrust in “EM drive” is found to be inaccurate.• Self-contradiction in physics is found in the concept of “EM drive”.• The theoretical foundation of the “EM drive” is found to be not solid.- end -Now, the difficulty with any emDrive theory is that it appears to be a quantum phenomena which requires one to pick a quantum mechanic interpretation or invent a new one.There are at least 18 major interpretationshttps://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics and a few dozen minority interpretations.https://en.wikipedia.org/wiki/Minority_interpretations_of_quantum_mechanicsThe leading contenders are:Copenhagen Interpretation - The standard interpretation which has a number of anomalies but has both historical traction and greatest momentum in universities. deBroglie Bohm Interpretation - This interpretation explains a few of the anomalies. Couder's work using oil drops to demonstrate macro level effects similar to quantum effects makes this an interesting approach.Gaining momentum but falls short of being comprehensive.Transactional Interpretation - Cramer's theory explains the most of the anomalies and is the leading interpretation. Kastner extends TI to quantum field theory (QFT). Comprehensive.The real difficulty for emDrive theory is that the effect may be relativistic instead of quantum mechanic. Enter Mach effects especially for any closed or open cavity with dielectrics. Mach effects rely on General Relativity and parametric amplification. Other efforts include Unruh radiation especially McCulloch and Dynamic Casimir effect. Both of which also are related to parametric amplification.Loop quantum gravity theory combines both relativity and quantum mechanics. This theory may eventually prove to be required for any propellentless propulsion system. In any emDrive theory, to ignore either quantum mechanics or general relativity is a rather dangerous game. Even so, one has to look at particle physics and quantum field theory to gain an appreciation and understanding of the complex processes occurring within the RF closed cavity system.About the best anyone can do is use a Feynman diagram to explain their theory. Such a diagram would permit experiments at the particle level and permit exploring beyond photons and electrons to the quasiparticle realm of phonons and polarons, and perhaps even Weyl fermions, massless charge quasiparticles.
Shut up and calculate
Quote from: Bob Woods on 01/05/2018 01:20 amQuote from: VAXHeadroom on 01/04/2018 10:55 pmQuote from: R.W. Keyes on 01/02/2018 03:44 pm...Expensive, but worth it. Can we start a cost-estimation?I do that for a living, and my group in NG builds some of the best cubesat hardware available. We can handle up to about 500W of power (continuous) and a projected reliability of >80% at 3 years in single systems or way better than that with redundancy (which we also support). That core HW, including flight software, launch costs, ground station support, and mission ops over a reasonable lifespan is on the order of $1M.How cheap CAN you get it? Probably <$100K but the projected reliability is in the trash can. Satellites in this cost range have a >50% likelihood to never be heard from once deployed and will never survive deep space radiation. Outside the Earth's magnetosphere, the radiation is HARSH.Monomorphic built his shell on a 3-D printer, with a copper film interior. Would those kinds of thermoplastics (?) be able to be space rated?EM引擎出现已经快20年了,尚未进入实用阶段,说明这个技术很不靠谱。尽管如此,好多人都想自己动动手,制造一个emdrive。据说,,,能够制造出来具有推力的引擎,并且得到公认的人并不多。那么如何制造这样一个引擎呢?有人制造过,却未能测到推力。他说费用在数万元。。。各位大婶,,各位大神。。。你们有没有知道怎么自行制造一个emdrive。。有没有资料。求共享。。
Quote from: Bob Woods on 01/06/2018 12:25 am"Help us Monomorphic, you're our only hope." Bob,wonderful as the Monomorph might be, he is far from being our only hope. Who knows how many builders or theorists there are out there, who will not publish till they are confident they can satisfy the critics
"Help us Monomorphic, you're our only hope."
At this point I am thinking it would be wise for all interested in a cubesat style experiment ( as I certainly am) to review TRL status of the concept and how that works during preparation for available launch vehicles.Another thread, in May, Robotbeat had a good comment, keep in mind the number of stakeholders required to actually achieve orbit..."...I do think there's some unnecessary ritual in the whole concept of the Technology Readiness Level formalism. It seems primarily a tool for getting multiple stakeholders to agree on whether a certain technology is mature enough for some application..."https://www.nasa.gov/pdf/458490main_TRL_Definitions.pdfWhat this means to me is quite simply, unless and until somebody has demonstrated suitable TRL no experiment will fly. Personally funding a launch is simply beyond my reach. YMMV
Quote from: Bob Woods on 01/05/2018 01:20 amMonomorphic built his shell on a 3-D printer, with a copper film interior. Would those kinds of thermoplastics (?) be able to be space rated?The PLA I used would out-gas in a vacuum. However, there is vacuum rated 3D printer filament available.
Just out of curiosity - why haven't anyone tested with array of thrusters/fustrums?It seems from the thread that the biggest issue for current and past tests is detecting reliable thrust signal from the background noise. Yet all developments have tried either to eliminate the noise sources.. or to elevate the power levels (also bringing up the background noise), but not adding to the thrust by adding thrusters.Yet - if I understand correctly - thrust is expected to come from the fustrum and it should not be extremely hard to place 2 or 4 fustrums on the torsion balance. Yes, it would elevate the weight - but would also multiply the thrust signal while leaving feeding system and overall design pretty much the same. One would also be able to switch on fustrums independently, getting additional thrust with each additional fustrum powered up, that should be visible from analysis. In theory it would also be possible to add thrusters on both sides of torsion balance, adding to the stability of the system..