Revolutionary Ion Thruster To Be Tested On International Space Station (abc.net.au) 132
Three Australian researchers have developed "an ion thruster that could replace the current chemical-based rocket propulsion technology, which requires huge volumes of fuel to be loaded onto a spacecraft." Slashdot reader theweatherelectric shares this article from the ABC News:
An Australian-designed rocket propulsion system is heading to the International Space Station for a year-long experiment that ultimately could revolutionize space travel. The technology could be used to power a return trip to Mars without refuelling, and use recycled space junk for the fuel... It will be placed in a module outside the ISS, powered, as Dr Neumann describes, by an extension cord from the station. "What we'll be doing with our system is running it for as long as we can, hopefully for the entire year on the space station to measure how much force it's producing for how long."
In the early 2000s "it was basically a machine the size of a fist that spat ions from a very hot plasma ball through a magnetic nozzle at a very high velocity," and the researchers are now hoping to achieve the same effect by recycling the magnesium in space junk.
In the early 2000s "it was basically a machine the size of a fist that spat ions from a very hot plasma ball through a magnetic nozzle at a very high velocity," and the researchers are now hoping to achieve the same effect by recycling the magnesium in space junk.
Could be dangerous (Score:3, Funny)
Didn't they watch Space 1999? The entire station could suddenly be thrust into an unknown part of the galaxy.
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Didn't they watch Space 1999?
Did you? Space 1999 started with an explosion at a nuclear waste dump on the moon.
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That's lots of ions...
This is the missing piece (Score:3, Funny)
Re:This is the missing piece (Score:5, Informative)
No it isn't. TLDR, read atomic rockets, n00b. Or, since you won't be reading it : high specific impulse ion drives have existed in various test forms for years. They are easy to make and they all have high efficiency, albeit some designs are more reliable than others. The problem with all of them is the nasty equation KE = 1/2 m * V^2. That means the higher the exhaust velocity (and thus specific impulse which is the fuel efficiency), energy required goes up with the square of exhaust velocity.
Plenty of ion thruster designs, including VASIMR, have reasonable energy efficiency. The problem is that you still have to pay the bill even if the efficiency were 100%. You still have to supply as much electrical power as the kinetic energy of the escaping propellant.
This is a big problem. Even the most exotic nuclear power generator designs anyone has drawn up, the nuclear generator is a heavy ass piece of equipment being propelled by barely any resulting thrust from the ion drive. It means that you might have great specific impulse but trips to Mars still take months. What you need is also high thrust. That's why the best engine for space travel that currently is feasible is still plain old nuclear-thermal. You only get an ISP of about 1000 (compare to 15k for this particular thruster), but you get thousands of times more thrust. You can complete your Mars injection burn in about half an hour instead of having to run the engine for months. That in turn increases efficiency because there is always 1 optimal point to do your engine burns at.
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Nahh, he's saying he's a fan of atomic rocket and he doesnt think anything else has the thrust to do what he wants, and so he does the circular firing squad thing that the space sector has been doing for the last fifty years.
Even if he is right, there is still a need for non time sensitive cargos of canned goods, metal powders for your advanced manufacturing printers, copper wire and all the other crap colonists will need, and thats where being able to go 'it'll take 500 days and we dont care' becomes impor
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http://www.projectrho.com/public_html/rocket/engines.php
I was introduced to it a few days ago after buying the video game Children of a Dead Earth. A space battle game using n-body physics.
He certainly could of been more eloquent in stating his case, quite unnecessary. As you r
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[EXIT STAGE LEFT, not having read Freefall for several weeks.] What are Flo and Co [purrsia.com] up to?
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Yes. http://spacenews.com/vasimr-ho... [spacenews.com]
Re:This is the missing piece (Score:4, Informative)
We know how Zubrin feels about VASIMR. There's also good reason to disagree with him. For example, his nuclear reactor criticism? He himself proposes building a powerful nuclear reactor to power colonies on Mars, so he's not self-consistent. His power density figures aren't anywhere close to realistic. He talks like 50W/kg is some sort of unachievably optimistic goal, when in reality ATK Ultraflex solar arrays already get 150W/kg (and MegaFlex 200W/kg), figures that have been going up significantly with time; high power nuclear designs for future space missions are measured in kilowatts per kilogram. His complaints about the funding that's gone to VASIMR versus other things are unfair, as VASIMR hasn't received all that much funding - certainly not enough to develop a nuclear reactor as he mentions. And nobody is going to develop a power system for VASIMR without having first validated the propulsion system (something Zubrin apparently doesn't want them to do). He tries to portray its various ion drive competitors as better, without mentioning that the primary reason for choosing VASIMR is its high peak thrust levels. Lastly, Zubrin's dismissal of the dangers of in-transit radiation is not shared by most researchers.
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1 kw/kg is still a tall order. You end up needing to use things like droplet radiators to even approach a number like that. As it so happens, solar panels are inherently much lighter because they can be a paper thin sheet of layered junctions - you can actually get much higher power/mass with solar than any heat engine nuclear reactor design anyone has drawn up. The only reason it sucks to use a solar-electric spacecraft to go to Mars is the sunlight incidence per square meter plummets to 44% out there.
I
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"Simple" is the last word I would choose to preface "nuclear thermal rocket". ;) ISPs on nuclear thermal aren't that great, and variable-impulse ion propulsion is much more mission profile flexible. And again: he calls for engineering high power nuclear reactors anyway, shipping them to Mars anyway, for things like ISRU - so why not use such a reactor en route, if you're going through the effort to develop one regardless? And contrary to your "before he personally dies of old age" statement, we're much c
Re:This is the missing piece (Score:4, Interesting)
It's a cylinder. Inside it are rods. The rods have channels in between. There is HEU fuel inside the rods and they are made of high temperature alloys.
For a practical Mars mission, your spacecraft would have 2-4 NERVA engines, each a little smaller than the last. On earth departure, you eject the rods that block the fuel channels and dampen the reaction. Engine is cold and has never been run at that point. You run the engine until the burn is complete. Then separate the hot radioactive mess of an engine that is melting down because when the propellant flow stops, so does the cooling.
That's the simplest way to do it. No nuclear power reactor, it's 1 time use. The pumps, radiation shield, and so forth you don't stage separate, you just eject the core and pressure vessel cannister it is. (so it can be extremely light, under a metric ton)
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You start the Mars injection burn in high orbit. You end it on a trajectory that will forever remain in solar orbit if no more engine burns are made. The engine is not radioactive when it is put in a rocket and launched, in fact you launch the engine unfueled and launch the fuel sections in separate rockets. Each fuel section would not have enough fuel to form a critical mass, so even in the worst possible accident the damage would be limited.
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The NERVA engineers were never able to keep the fuel rods from cracking and chipping under thermal stresses and pressures from the reaction mass, making it too unreliable to use in practice (one of the reasons the program was abandoned). It's possible that's a problem that could be addressed, but of all the technologies discussed on this thread nuclear thermal is the one with the highest technical risk. It would be far easier and cheaper to build a nuclear reactor.
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That's not at all what the articles say on it. It says it was essentially a flight ready technology. A few chips can either be solved by better QC or just determining the probability of failure due to the chips. 0% chance of failure is never possible, any vehicle humans has ever invented has a nonzero chance of failing spontaneously and killing you in use.
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No, it's nowhere near flight ready. The chipping problem isn't caused by bad QC; it's caused by stresses on the rods.
There's a reason nobody is seriously contemplating use of this technology.
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The only reason it sucks to use a solar-electric spacecraft to go to Mars is the sunlight incidence per square meter plummets to 44% out there.
I know folks are working very hard on space based lasers. They've become a lot more powerful and cheaper over the past decade. Of course, they have to be careful with the wavelength or suddenly they have an orbital weapons platform, rather than a propulsion, but... it could be a nice combination with the solar sails.
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Unfortunately the math doesn't work out for trips from Earth to Mars. A laser, like any other source of light, is still subject to the 1/r^2 law. The r is the effective radius of the lens, which you can make pretty big, but Earth to Mars is an enormous distance and only a tiny fraction of the energy would hit a solar sail a few kilometers across with a practical mirror you could make in orbit.
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Well, these guys (http://www.deepspace.ucsb.edu/projects/directed-energy-interstellar-precursors) seem to think it may work, at least for small packages.
"As an example, on the eventual upper end, a full scale DE-STAR 4 (50-70 GW) will propel a wafer scale spacecraft with a 1 m laser sail to about 26% the speed of light in about 10 minutes (20 kgo accel), reach Mars (1 AU) in 30 minutes, pass Voyager I in less than 3 days, pass 1,000 AU in 12 days and reach Alpha Centauri in about 20 years. "
Apart from Mars
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Oh, since you probably won't read the whole article, the key paragraph is this :
"But wait, there’s more. To achieve his much-repeated claim that VASIMR could enable a 39-day one-way transit to Mars, Chang Diaz posits a nuclear reactor system with a power of 200,000 kilowatts and a power-to-mass ratio of 1,000 watts per kilogram. In fact, the largest space nuclear reactor ever built, the Soviet Topaz, had a power of 10 kilowatts and a power-to-mass ratio of 10 watts per kilogram. There is thus no basis
Re:This is the missing piece (Score:4, Informative)
It's a stupid comparison that's not to Zubrin's credit. The reason that no powerful space nuclear reactors have been developed is because there hasn't been any demand for them. Nuclear reactor power to weight ratios don't scale up linearly, they scale up vastly higher than linearly. Figures of 1000W/kg aren't just some sort of out-of-a-hat fantasy numbers, they're based on the very real work in the field. More to the point, even solar is already in the low hundreds of watts per kilogram, so again, Zubrin's acting like 10W/kg is the state of the art and 50W/kg overoptimistic is beyond absurd.
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Figures of 1000W/kg aren't just some sort of out-of-a-hat fantasy numbers, they're based on the very real work in the field.
Care to cite? I've looked fairly extensively for anything on this, and no, everything I read said it was fantasy.
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There's a nice breakdown here [nasa.gov] for different technologies, table 1. Keep in mind that they cite things in kg/kW, not kW/kg; you have to have an energy source, energy conversion, and heat rejection mechanism - and if it's manned, a neutron shield (although there's a variety of possibilities beyond a dedicated shield, such as shielding with cargo, propellant, significant distances, etc); and that the conversion efficiency must be accounted for.
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Ok, so 3 kg / kw electric is 3 times worse than it "needs to be" for a 39 day trip to Mars.
Terrible. And if I actually look at the chart you linked on page 3, that's solid core fusion (0.15 kg/kWout) + Rankine Heat Engine(.14/kg heat IN) + Neutron Shield(1 per kw HEAT) + single phase radiator, 600 K(.98 kg per kilowatt HEAT).
I already know this is going to be terrible? Why? Because it's talking about HEAT kilowatts. With 600 K radiator (efficiency is even shittier at higher radiator temperatures, see th
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Why are you pretending that there were only the technologies that you hand-picked available, when the table actually listed numerous options with a wide range of masses? Why are you pretending that a neutron shield must be inert mass used for nothing other than shielding, and that increased distance between crew and propulsion isn't likewise an option? Why are you pretending that the table doesn't already list conversion efficiency? How close attention did you actually pay to what you were reading?
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Because nothing else on the table exists as a real system.
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I may come off as terribly ignorant now, but would it not be reasonable to use such an engine for a cheap permanent ferry between Mars and Earth that never stops? It could spend a few years gaining velocity before it gets put into use.
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The big problem with fission -> electric -> ion drive is that your fission reactor needs a cold sink which can absorb its entire power output. To do that you will need a lot of radiating surfaces and associated plumbing. It adds up to a lot of mass, perhaps more than the reactor and shielding.
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That's what I said. _Although_ you could use droplet radiators to reduce that problem hugely.
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Well, just wait ten years for controlled fusion power.
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Are you trolling? Of course fusion would be nice, but there's very little reason to think that lightweight, controlled fusion is imminent. It might happen but I wouldn't bet on it.
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Not trolling, joking. Controlled nuclear fusion has been ten years off since I was a boy in the 1950s. It's become a trope.
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Oh. Sure. I mean it's not totally out there. Obviously you can do it, easy, with a few bits and bobs to make a radiation lens and a wee little nuclear bomb to get the party started. Works great. So doing the same thing, just on a smaller scale with a tiny puff of fusion fuel gas, has always seemed to be right around the corner. If a bomb that weighs under 100 kg can do it on a large scale, why can't you make it happen on a small scale with 100 tons or so of apparatus, including lots of superconducting
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100 years of 10 pounds of thrust never stopping, will get you going INSANELY fast in space.
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Voyagers 1&2 are closing in on 40 years, and only their limited power supply will force them to shut down. Granted running an engine that long is likely to be significantly more complex than other instruments.
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Voyagers 1&2 are closing in on 40 years, and only their limited power supply will force them to shut down. Granted running an engine that long is likely to be significantly more complex than other instruments.
Totally incomparable. My multimeter is as old as my long dead first car.
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That's because you are a Luddite who doesn't understand that computers got better, therefore everything gets better.
Why, the first Boeing 747 flew in 1969 and took 6 hours to cross the Atlantic. My cell phone has more memory than that 1969 plane, therefore it must fly much faster now.
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I had a 40 year old electric drill (Oster brand!) that I inherited from my father. It did finally wear out, though, after lots of use. I was kind of glad; it used a cord, and the battery kind is much easier to use.
Which makes me think--maybe this spacecraft just needs a very long extension cord!
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I have a Multimeter that was new in 1941 and it's currently far more accurate and reliable than anything you can purchase today.
SO sad that simpson meters are not like they used to be.
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Yes, a radio floating in space on inertia alone is exactly the same thing as massive machinery designed to generate power.
Things are always so simple when Space Nutters/programmers are in the conversation, one wonders how come they haven't colonized Jupiter yet. It's simple, send a 3D printer to the Asteroid Belt, 3D print some terraforming machinery and nuclear space rockets, send all that stuff, and the 3D printer, to Jupiter, and within weeks it'll be just like the Bahamas.
Simple, and easy to do. It's th
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The problem with all of them is the nasty equation KE = 1/2 m * V^2. That means the higher the exhaust velocity (and thus specific impulse which is the fuel efficiency), energy required goes up with the square of exhaust velocity.
But thats just your input electrical energy being turned into kinetic energy of the reaction mass, and ultimately the vehicle.The more energy you pile on at that point, the more velocity change you get.
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Yes but the heavier your power generator needs to be. So the higher the ISP, the worse the effective thrust. The worse the thrust, the longer it takes to get somewhere.
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Well okay but its better overall than liquid fuels and if you want to send a pipeline of supplies to mars, its a good way to do that, while inefficent fast cruise stages take the humans.
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More or less. Uncrewed nuclear-electric "barges" have the obvious problem that they are technically very complex and if anything goes wrong, there is no crew aboard able to conduct repairs. Also, nuclear reactors meant for space might be extremely expensive, the cost exceeding the cost of a few heavy-lift rocket runs full of fuel. As Mr. Musk has demonstrated, it's entirely possible to launch rockets that are mostly reusable, so the cost of a few swimming pools full of additional propellant might not be
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But uncrewed solar electric barges are well validated technology. There is one orbiting Ceres right now. With a top up of reaction mass it could keep going for decades.
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Ion thrusters aren't the best for Mars colonization, because then it takes too long to get to Mars. The trip to Mars is very dangerous, due to space radiation and the effects of microgravity on human health. For actual colonization, as opposed to just an Apollo-like exploration mission, you want to minimize the transit time. In Andy Weir's "The Martian" (he worked out a realistic plan for a Mars mission and did all the math), ion engines are used, but the travel time is 250 days. In Musk's plan, powerful ro
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Then simply 3D print ion thrusters on Mars and bring Mars closer to the Earth.
Do I have to do *all* the thinking around here?
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Because we will need to send several satellites first. this engine will make those nuclear powered birds able to keep their orbits without carrying a metric buttload of fuel.
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Will this be doable?
can we have 10 ion thruster vehicles doing Earth Mars round trips until they until they reach a decent speed? then every time we want to send something to Mars send a module with just enough fuel to match speed with whichever one is closer to Earth at that moment and hook to it?
It would not be easier but I don't thing is beyond our capabilities and the cost expensive at the start will be reduced by multiple uses
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If you have an experiment that shows a violation of conservation of momentum, the correct response is to send a grad student down to find out where the mistake is.
Not hold a press conference and start packing your bags for Proxima.
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Sorry, the missing piece is a closed cycle ecology. Well, nearly closed. This could be important, but it's not crucial as there are other ways of making ion rockets work in near-solar space. But the closed cycle ecology is needed if you want to get people living away from Earth. (i.e., the general category of "flexible ion rocket" is extremely important, this particular gadget is one possible implementation. But even all together without a [nearly] closed cycle ecology you're only facilitating robot ex
Interview with Dr Neumann (Score:5, Informative)
For those interested, there is a lengthy and interesting interview with Dr Neumann about this on The Space Show. http://thespaceshow.com/show/0... [thespaceshow.com]
It Just Can't Be (Score:2, Flamebait)
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I haven't worked with NASA, but my experience is that a lot of US academics and technology businesses are very introspective and suffer from major issues with NIH.
Some more information (Score:5, Insightful)
Hi,
I'm Ian Whitchurch, the CEO of Neumann Space.
First of all, if you want more technical information about the Neumann Drive, there's an article in Applied Physics Letters. It may be available here
http://scitation.aip.org/conte... [aip.org]
If that isnt working, then you might know someone with an APL subscription, or it might be somewhere on the internets under "A centre-triggered magnesium fuelled cathodic arc thruster uses sublimation to deliver a record high specific impulse Patrick R. C. Neumann, Marcela Bilek and David R. McKenzie".
Secondly, it's not just the Neumann Drive that's going up to the Bartolomeo platform on the ISS. We're planning on taking a bunch of other peoples small projects, which deserve to go into space, but cant by themselves get a ride into orbit, or an easy method to get power, heating, cooling and communications once they are there. If you're interested, you might want a look at this fine Airbus DS press release.
https://airbusdefenceandspace.... [airbusdefe...dspace.com]
There is also information available about the Facility for Australian Space Tests on our website, at http://neumannspace.com/fast/ [neumannspace.com]
Thirdly, Im happy to answer further questions people might have.
Finally, our poor, poor website. Also, the original post lacks a poll, which itself lacks a Cmdr Taco option. What the heck am I supposed to vote for ?
Re:Some more information (Score:4, Informative)
Thanks for chiming in and linking the paper, and my apologies for exposing yourself to the comment environment here, which has become rather toxic concerning space issues of late. The fact that the press coverage comes across as "hype-y" doesn't help any.
While I think your premise of using space junk is... let's say "optimistic", in the anywhere-close-to-near-term timeframe.... the engine concept itself seems quite sound and interesting. I can't read the paper (not going to shell out $30 for it... not your fault I know, the publishing world is terrible), but - how sensitive is it to the geometry of the cathode? Is your concept that things would be melted down and cast (or extruded, or any other mechanism) into your desired geometry? I assume that at present you're doing something like feeding in wire off a spool to act as the cathode?
Re:Some more information (Score:5, Informative)
It's press coverage - it's going to be hypey, and thats just the world we live in. As indeed is toxic comment environments :)
While running on space junk would be nice, it doesnt need to happen for the drives to be useful. If you're rocking 11 000s of specific impulse, then it's simple enough to bring a shipment of cathodes up from earth, transfer to a SEP tug and take them to where they are needed. The fact they are solid, and therefore dont need to be kept at the correct temperature and pressure helps a lot.
Cathode geometry is something we need to do more science on. At the moment, we've been working with one inch diameter circular cathodes, and the 'star' erosion pattern appears to be a thing. Yes, we're definitely looking at cast/extruded cathodes. We've got some ideas about how to move cathodes forward, and thats on the 'to do' list for the model thats going up to the ISS.
Sloppy diagram (Score:3)
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Wow - thanks for commenting here and welcome. Please excuse the rude ACs.
I'm curious about the using space debris as fuel, if I read that right? If magnesium is the top "fuel" can it use something like aluminium and have a lower specific impulse?
I think Cmdr Taco is jealous of Dr Neumann's beard!
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If it's solid and conductive or semiconductive, we can use it.
That said, Im expecting to find worse power efficiency as well as lower specific impulse from "mixed metal fuel rods" - but if you didnt have to pull it up from the bottom of a gravity well, it might be worthwhile.
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thank you, I hope we see these engines buzzing around the solar system, I am fascinated.
I'd imagine when you have more current you can accelerate faster?
What about radioactive metals, depleted uranium for example, does the engine behave differently because the fuel is a radio isotope?
Comparison, please (Score:3)
How does the energy input and thrust produced compare to NASA's current operational ion engine, which has been in use on the Dawn mission for the last ten years?
Re:Comparison, please (Score:5, Informative)
http://descanso.jpl.nasa.gov/S... [nasa.gov] is as good a summary as any about NASA's current ion engines, while the APL paper by Neumann, Bilek and McKenzie for the http://scitation.aip.org/conte... [aip.org] has information about the Neumann Drive.
Short version is that xenon drives vary in specific impulse and power efficiency depending on the power levels, while Neumann Drives vary in specific impulse and power efficiency depending on the fuel used, while the power level affects how many pulses per seconds. Higher power levels appear to cause faster wear of the grid in Gridded Ion Thrusters, or the chamber in the case of Hall Effect Thrusters, as well as needing more investment in Power Processing Units and so on. Additionally, there is the issue of tankage, regulators and so on for dealing with the xenon itself, which means it's not a straight 1:1 comparison. That said ...
TLDR : Magnesium in a Neumann Drive runs about 9 uN/watt and 11 000s specific impulse. A NSTAR running at ~1000 watts input has about 32 uN/watt and 2850s of specific impulse.
Re:Comparison, please (Score:4, Interesting)
The Neumann thruster is all about saving launch capacity. Most of the ion thrusters we have now work with e.g. Xenon gas; you have to loft their fuel, and your engine mass budget has to include the material handling for the propellant; tanks, valves, etc.
The idea of the neumann thruster is that your reaction mass comes from a simple sold puck which is gradually ionized; so you immediately win on a bunch of hardware you don't have to lift.
And then, you can use as reaction mass the sorts of stuff which is already up there in orbit. Got some excess second stage, which you've lofted to orbit at ruinous cost? Instead of dropping it back into the atmosphere to burn up, melt it into a puck at the focus of some mirrors, and then use it as reaction mass for a few years.
Space junk turned into valuable fuel. Big win. .... IF it works.
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Not fuel, reaction mass
The main problem is safely grabbing the space junk (Score:5, Insightful)
The problem with space junk is less about getting to it and more about getting to it safely. Everything in orbit is travelling a minimum of 17,000 mph. Have you seen what happens when car into a wall at only a 100 mph difference? Think two flimsy satellites colliding with a 400 mph difference. There will be hypersonic shards of metal everywhere.
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The problem with space junk is less about getting to it
Actually, that is the problem. Maneuvering to intercept a piece of space junk requires a huge amount of energy when you're already traveling 17,000 mph, that's a lot of momentum to change.
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But the junk you're trying to reach is also moving exactly at orbital velocity for whatever orbit it's in, it's just at a slightly different angle. And almost all of it is moving in nearly the same orbit. So the difference in velocity would be relatively small. Of course, "relatively small" is still pretty large, but the GP's estimate of 400 mph is probably a reasonable guess. But the masses are low, so a reasonable catcher is probably possible. But you'd need to wait until a shard approached you (pref
Probably just making a point (Score:3)
... There will be hypersonic shards of metal everywhere.
Um, I know this may be a dumb question, but I'm trying to get a handle on how fast those shards would be going.
So, what's the speed of sound in space?
Thanks,
P. Edant.
The speed of sound is dependent on temperature, but doesn't vary all that much - 1200 km/h to 1000 km/h at about -60 C.
Once you get to vacuum, "the mean free path" of the particles becomes so long that the atmosphere begins to act less like a gas and more like individual particles. Changes in pressure are not propagated efficiently in this situation, so the idea of "sound" starts to lose its meaning.
I think the OP was just making a visceral point. If we use the sea-level 1200 km/h speed and note that orbita
Ion thrusters were invented in 1959 (Score:2)
The first use of an ion thruster as the main engine was in 1998 in Deep Space 1. Russians use it quite a bit to correct orbits of some of their satellites. IOW this is not a new technology.
Big difference in these ion thrusters. (Score:2)
Neumann thrusters work very differently from existing ion thrusters, though. At a high enough level, the concept is the same - ionize some stuff, accelerate it using an electric field - but the details matter a ton. Or, indeed, several tons. The existing ion thrusters mostly use gases - xenon is popular - as reaction mass. That means your reaction mass is already conveniently in tiny individual particles (single atoms, since it's a noble gas) suitable for extreme acceleration, but it also means you need to
EM Drive -v ION drive = 1st space robot wars (Score:5, Interesting)
I'd like to see an EM Drive [emdrive.com] put into testing up there too (yes, yes, yes - I know it's defying the [known] laws of science [slashdot.org]. No reason not to test it in space since it seems to pass all tests on earth)
Hey maybe we could strap the ION Drive face-to-face with an EM Drive, throw them out the hatch and see who pushes who around!
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*shrug* If they want to be a customer, Im happy to sell them space and give them a power allowance.
Re: EM Drive -v ION drive = 1st space robot wars (Score:1)
So, knowing nothing about the particulars of an emDrive...
What would it cost to get a 1kW 50kg half-height fridge a ride-along with you? Is this "ambitious Kickstarter" territory or "have a rich uncle Gates or Bezos" territory?
What are the primary driving constraints? Size? Weight? Power?
Thank you again for dropping in on Slashdot to discuss this.
Re: EM Drive -v ION drive = 1st space robot wars (Score:4, Insightful)
Is this a casual conversation, or are we talking, like *numbers* here ?
If it's the latter, the 1kW is going to be the biggest constraint - you're asking for a lot of power.
As far as costs go, I'd say we're looking at 'not especially ambitious' Kickstarter, especially if you're happy for it to not come back, and to cut that power demand down a little.
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Name one breakthrough in science which was made by a crackpot -- someone who was dismissed as not being a real scientist, rather than simply considered to be incorrect by fellow scientists.
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vulcanized rubber - Goodyear was a loon, read his story sometime. wore gooey smelling clothing articles made of rubber his was experimenting with, house had globs of rubber on wall, in kitchen, poisoned himself with his experiments
AC motor, generation and transmission tech - many of Tesla's ideas just wrong, we use others daily. He was a weirdo
science of genetics - Mendel was dismissed as crackpot during his life (you know of the monk's S&M cocaine orgies right?), value of his work realized almost two
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(a) Appeal to authority. [yourlogicalfallacyis.com] Facts are true or they aren't, and the majority opinion of scientists doesn't affect that.
(b) Catastrophism [wikipedia.org] was proposed by J. Harlen Bretz [wikipedia.org] as an explanation of the geologic features of the Channelled Scablands [wikipedia.org] in Washington state. Basically he mapped out a bunch of geologic features and proposed that they were created by a catastrophic event: the unleashing of a tremendous volume of water that carved out new geologic features in a matter of days.
He was completely dismissed as a c
Crackpot [Re:EM Drive -v ION drive = 1st space r (Score:1)
"Crockpot" is probably relative. Einstein's ideas were greeted with skepticism, bordering on ridicule, as was the multiverse model of quantum physics. Even rockets working in the vacuum of space was bashed by some in the mainstream.
There is often groupthink and "best practices" of the time, and going against those can get one labelled as a crackpot. Humans naturally protect their turf.
I've been labelled such myself for claiming that human grokkab
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Did I wander into a tangent here?
Yes, but you are right! 8-)
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Fleming wasn't considered crackpot at the time
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No, he was accused of fraud and patent infringement and poor management.... not being nuts. He received awards for his invention.
Some of his predictions are funny: "As a growing competitor to the tube amplifier comes now the Bell Laboratories’ transistor, a three-electrode germanium crystal of amazing amplification power, of wheat-grain size and low cost. Yet its frequency limitations, a few hundred kilocycles, and its strict power limitations will never permit its general replacement of the Audion
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That might be true, but doesn't invalidate the original point.
Christopher Columbus was also nuts, and a more sane person probably wouldn't take the trip. Serendipity is sometimes fueled by stupidity.
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Anyone who wants to fund the experiment is of course free to do so. I'd advise against it though,. The EM drive claims to violate conservation of momenum (4-momentum if you are being picky), under conditions that are not in any way outside the range of typical experiments. The theory, at least as presented in the AIP advances doesn't make any sense at all. The experiments are tricky and easy to get wrong. (the thrust is tiny so forces on cables etc could easily distort the measurement).
I know the argumen
Last link (Score:2)
The last link says something about recycling space junk but it is just a link the wiki page on ion thrusters.
Is there an actual article about this and is there research in this area?
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Personally, I'd start by looking at the work on solar furnaces and space manufacturing.
Actual links (Score:2)
http://neumannspace.com/ [neumannspace.com] - the web site of the company / research lab building these things. Kind of hype-y, of course, but has some good info.
http://neumannspace.com/scienc... [neumannspace.com] - the section of the site that gives an overview of how the Neumann thruster actually works, how efficient it can get, and so on. Includes links to blog posts about a number of the fuels they've tested, such as http://neumannspace.com/blog/f... [neumannspace.com] (which has an utterly ludicrous specific impulse).
It's better for cargo then for people (Score:3)
However, ion thrust technology has some real problems when it comes to moving people around the solar system: transit time. If you look at this [neumannspace.com] description, it turns out that the fastest travel time from Earth to Mars they quote is seven months. That's not from LEO but from a station at L5 to a Mars orbit where there is another orbiting station. Getting out of the gravity well is assigned to chemical rockets. This architecture requires a lot of infrastructure investment. Without these stations it's likely the transit time are much longer, closer to the 9/18 month burn and coast transfer orbits.
Long term exposure to weightlessness is not good for humans. For example, space station cosmonauts (tweaked you on that one) have long term vision problems. Even worse is the radiation exposure outside the Van Allen belts. The manned mission to Mars community, including NASA, seem to be underestimating the seriousness of this problem. It's not just about cancer. There are other long term problems like heart disease and general decline in health and longevity. For example, the long term effects of exposure to radiation from Chernobyl have been terrible in affected areas in Belarus and the Ukraine. (There is a huge coverup over this situation, so you don't hear anything about it. Even the World Health Organization seems to want to sweep it under the rug.)
It's surprising that no one here has made any comparison to the recently released road-map from SpaceX. They propose a 30 day transit time without needing any orbital infrastructure either at Earth or at Mars. They are further along then Neumann, having their first generation hardware already proving itself in space flight, while Neumann is only now doing a flight test. Even so, it's unclear if ion or chemical engines are the best way to send humans to Mars, assuming that is a good idea in the first place,
Looking at the specs, if the Neumann system works as advertised it would be well suited for exploring the outer solar system. If paired with an RTG It would allow significant size missions to the outer planets that could go into orbit and not be limited to flybys. They confidently describe continuous acceleration for years at a time with a single fuel slug weighing in at a few kilograms. Even though manned missions to Mars are more glamorous, exploring the solar system is equally important in the long run.
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Early 2000's (Score:2)
interesting but doesn't solve the big problems (Score:2)
This is quite obviously *not* any sort of general replacement for chemical fuel due to the low thrust. A Nuclear Salt Water Rocket or Fission Fragment rocket otoh might do it. I wonder if this tech would be useful for micro-ships.
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I think its Space Porn.
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nope, you want very light ion because the specific impulse/efficiency advantage is entirely due to high exhaust *velocity* not mass