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Space Technology

New Ion Engine Being Tested 217

Posted by Zonk
from the warp-factor-one-engage dept.
Dr Cool writes "A new design of spacecraft ion engine has been tested by the European Space Agency which dramatically improves performance over present thrusters and marks a major step forward in space propulsion capability. Ion engines are a form of electric propulsion and work by accelerating a beam of positively charged particles (or ions) away from the spacecraft using an electric field. ESA is currently using electric propulsion on its Moon mission, SMART-1. The new engine is over ten times more fuel efficient than the one used on SMART-1."
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New Ion Engine Being Tested

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  • cool but (Score:5, Interesting)

    by ShaneThePain (929627) on Sunday January 15, 2006 @01:41AM (#14474376) Journal
    Ion engines are high impulse, low torque, so they are appropriate only once your already IN space. even then, there is extremely slow acceleration. I think the construction of a space elevator http://en.wikipedia.org/wiki/Space_Elevator [wikipedia.org] would be a much greater step towards "casual" space flight. even so, very cool.
    • Re:cool but (Score:5, Insightful)

      by dbIII (701233) on Sunday January 15, 2006 @02:03AM (#14474450)
      I think the construction of a space elevator
      Dyson spheres and FTL travel are also very cool too and also have nothing to do with this - the benefit of this ion engine is we can build it now with materials and techniques in use now instead of unobtainium or obtainium-next-year-for-sure.
      • "Insightful"? Do you mods even bother reading the posts?

        OP: Ion engines are high impulse, low torque, so they are appropriate only once your already IN space.

        You. Can't. Get. Into. Orbit. With. This. Ion. Drive.

        Parent: Dyson spheres and FTL travel are also very cool too and also have nothing to do with this

        Of course. That's why the OP mentioned the space elevator. You can't get to Mars with only a space elevator, and you can't get into space with only an ion drive. They're complementary, not com

    • Re:cool but (Score:5, Funny)

      by abes (82351) on Sunday January 15, 2006 @02:05AM (#14474458) Homepage
      The space elevator seems okay, but I'm putting my money on the space catapult. The one downside is the giant net you need to catch the 'passangers'.
    • Re:cool but (Score:5, Informative)

      by asadodetira (664509) on Sunday January 15, 2006 @02:07AM (#14474465) Homepage
      The low torque is not a big concern. In space you can rotate a spaceship any way you want by using gyroscopes.

      Conservation of angular momentum says that if you turn on a gyroscope, the spaceship must start rotating in the opposite sense so the total angular momentum is the same as in the beginning. At some point you stop the gyroscope and the ship stops rotating.
      • Re:cool but (Score:3, Informative)

        by Anonymous Coward
        Not torque in that sense, but torque as it is used in an automotive engine. A higher torque means that you can accelerate quickly from lower speeds. These are indeed a very gentle acceleration, but can achieve a very high velocity after a long time I believe these are quite energy effecient, and so can provide accelleration for pretty much the entire trip, unlike conventional thrusters which dump large amounts of fuel. Well, the Ion thrusters would at least be able to accelerate for half the trip, before
        • However, Ion drives efficiency over chemical reaction trusters is often more than offset by the fact that it is much more efficient to use your propellant when deep in a gravity well than it is to do so over the breadth of the mission. Ion drives also force you to make multiple passes through earths van-allen belts which increases the shielding needed to protect the electronics.

          When you subtract the energy needed to boost the reaction mass used mid-cruise out of low orbit & the additional shielding, ion
      • Re:cool but (Score:3, Informative)

        by DarkOx (621550)
        Well yes you could change the orientation of the craft that way. Unless you actually apply some force away from the craft you won't change the trajectory its traveling at. So all the gyroscope is going to let you do is point the craft in the direction you want and let the ion engine gradually start pussing you in that direction while you continue to travel in the old direction.
      • The low torque is not a big concern.

        Indeed torque can be a big problem in space, even if you have gyroscopes.

        If the propulsion engine has a small offset in thrust wrt the center of mass of the spaceship, this generates torque. The gyroscopes can absorb this by accelerating, but only up to a certain amount (because, obviously, they cannot continue to increase their speed indefinitely).
        At that point the gyroscopes must be "unloaded" by firing some appropriate thruster and consuming propellant.

        They h

      • I think one can assume he meant thrust, but used the word torque because he's thinking in automotive terms. The ability of a car to accelerate is conventionally expressed as the torque the engine delivers, which gets translated into thrust by the drive train and wheels.

        rj

    • Collanders. Giant space Collanders.
    • Last week, Slashdot introduced a thread discussing how high-powered magnets might propel spacecraft at warp speed [slashdot.org]. In essence, we are talking about a warp engine.

      Now, according to the present thread of discussion, the European space agency is developing a new ion engine. In essence, we are talking about an impulse-powered engine.

      Warp engines. Impulse power. Hmmm.

      So, when do we make "first contact" with the Vulcans?

      • So, when do we make "first contact" with the Vulcans?

        After WWIII of course. I just hope we're the mirror universe.
      • is developing a new ion engine. In essence, we are talking about an impulse-powered engine.
        I suspect the first ion thrusters predate the first series of Star Trek by a few years. They have been used for keeping satellites in station for a long time and can be used for years with very little fuel.
    • Being on /. I didn't bother to go RTFA, but I really doubt they are using it as a method to get into Orbit. I know NASA is considering (developing?) using this for the Mars mission as a method to shorten it's round trip to something a little more reasonable than 6 years (IIRC that's what the round trip takes with current propulsion).
    • These would be ideal for use in heavy lift space going airships. http://msnbc.msn.com/id/5025388/ [msn.com]
  • by drrngrvy (873112) on Sunday January 15, 2006 @01:44AM (#14474391)
    Look, we still can't go faster than light, ok guys [startrek.com]?
      • But how quickly can YOU travel through a Bose-Einstein condensate?

        Besides, that article has multiple instances of my most annoying literary pet peeve: Vacuums hundreds of trillions of times lower than> and temperatures almost a billion times colder that that appear in one sentence. Joy.
    • by Anonymous Coward
      Aparently we can (in theory) with a large enough magnetic field and by using it to slip in to another dimension. In fact, I think we are rather ingnorant/arogant in thinking that we know that we can't go any faster than light. When people used to discuss speed, it was common knowlege that one could not go faster than 60miles per hour and still be able to breathe properly (or at all). I forsee a day when people will laugh at our naivety in relation to our perception of relativity and quantum physics.
      • by XchristX (839963) on Sunday January 15, 2006 @04:11AM (#14474758)
        [quote]

        Aparently we can (in theory) with a large enough magnetic field and by using it to slip in to another dimension. In fact, I think we are rather ingnorant/arogant in thinking that we know that we can't go any faster than light. When people used to discuss speed, it was common knowlege that one could not go faster than 60miles per hour and still be able to breathe properly (or at all). I forsee a day when people will laugh at our naivety in relation to our perception of relativity and quantum physics.

        [/quote]

        Sorry, but that is just double naysaying. The above example you cited about the 60mph thing (as well as other claims now disproven, like you cant exceed the speed of sound etc.) was not based on hard facts, but vague conjecture and speculation. Furthermore, the dogma in those claims was obvious from the fact that they were deemed "impossible". Nothing is truly impossible. ButFTL acceleration is not impossible. It is completely meaningless as it simply violates causality. If FTL accn is possible, then our entire understanding of physics is almost completely wrong, and there is ample tangible evidence to suggest that is not so.

        Furthermore, as a physicist, I do NOT laugh at the 'naivety' of the physicists of the last century at all, or the century before that. I know they made some mistakes and reached some false conclusions. I am also aware that everything that we know about the natural world today can be traced back to their work. Even quantum and statistical theory could not have been possible without the knowledge of Newtonian Mechanics and classical thermodynamics. If the scientists of the future look back and ridicule us for our efforts, they would be ignorant fools who dont realize that their understanding of physics has improved because of what we have discovered in this time.

        I know that real scientists will never be as arrogantly clueless as you, or the folks who modded you up are, though.




        • by Anonymous Coward
          "ButFTL acceleration is not impossible. It is completely meaningless as it simply violates causality. If FTL accn is possible, then our entire understanding of physics is almost completely wrong, and there is ample tangible evidence to suggest that is not so."

          I wouldn't say that. What about Quatum tunneling?

          http://www.npl.washington.edu/AV/altvw75.html [washington.edu]

          "In particular, Aichmann and Nimtz have recently transmitted Mozart's 40th Symphony as frequency modulated microwaves through an 11.4 cm length of barrier wav
          • by hweimer (709734)
            "In particular, Aichmann and Nimtz have recently transmitted Mozart's 40th Symphony as frequency modulated microwaves through an 11.4 cm length of barrier wave guide at an FTL group velocity of 4.7 c, receiving audibly recognizable music from the microwave photons that survived their barrier passage. The transit time through the barrier was about 81 picoseconds and was observed to be constant for barriers with widths varying from 4.0 cm to 11.4 cm."

            Nimtz is a clever PR guy but a lousy physicist. Every physi
        • But come on dude, you have to admit, some asswhole idiots have slowed down science because of their
          egos. Some so called popular ideas do end up being bolony.

          We also know how crap the business end is... its not all pure science, there are idiots out there that
          will kill an idea if it means money for them... To some people after 30 years, its just a job and they like
          the easy money, to the young ones its all cool. Didnt someone once say, that all scientists make their true
          best only discoveries in their 20s, the
        • ButFTL acceleration is not impossible. It is completely meaningless as it simply violates causality. If FTL accn is possible, then our entire understanding of physics is almost completely wrong, and there is ample tangible evidence to suggest that is not so.

          Indeed, carefully worded. I seem to recall that there are no restrictions on actually travelling faster than light, only that accelerating to the speed of light requires infinite energy, yes?

        • I should point out, and I know this is the fault of the grandparent not the parent, that the word is "naiveté", prounounced "naive-tay". There is no such word as "naivety". How would you pronounce it, anyway? "Naive-uh-tee"?

          The naiveté of such a suggestion almost makes me laugh :)
      • Apparently pulsars can sustain incredibly powerful magnetic fields and still remain in this dimension. Even mutual electron-electron repulsion (the strongest manifestation of the electromagnetic force with baryonic matter) is incapable of holding the atoms apart, so the electrons and protons merge, making a soup of neutrons (which are held apart by the strong nuclear force if I remember correctly).

        Anything we build is based on the electromagnetic force (bolts, welding, internal cohesion, adhesives, magnetic
    • Look, we still can't go faster than light, ok guys?

      If we could just contact Sigma Draconis VI [startrek.com] we could skip past warp drive altogether!

    • Got an idea (Score:2, Interesting)

      by dascandy (869781)
      What if you view the speed you're going at as a 4-dimensional vector with the basic 3 axis of space and the axis of time. That way, speed would (should) be a constant, where, if you accelerate more in the space domain in any direction, your speed in the time domain would decrease. Now, if you could accept that travelling faster than the speed of light is impossible only due to this vector being constant in size, you could accelerate until it is on the other side of the timeplane, thereby allowing you to tra
      • Speed = space / time.

        Could you reword your post performing the substitution of this simple definition? ('cos I'm not sure that in it's current form your words convey any meaning at all.)
  • Deep Space 1 (Score:5, Interesting)

    by saskboy (600063) on Sunday January 15, 2006 @01:47AM (#14474399) Homepage Journal
    I remember reading about Deep Space 1 and it's Ion engine about 8 years ago. I was most impressed that the thrust is about that felt on your hand by a piece of paper when held on Earth. The key is that it accelerates the ship to a speed much greater than traditional rockets, not how quickly it does that. Besides, you don't want to go from 0 to 60 in .058 seconds, unless you want to be a smear on the bulkhead.
    • Re:Deep Space 1 (Score:3, Insightful)

      by Burz (138833)
      However it seems that the packaging for this new engine is also far smaller than the breed of ion propulsion, and will greatly increase the thrust available to a spacecraft. Its not clear yet whether that will be an order of magnitude increase, or something smaller. But it does appear to be enough to open-up exploration of the solar system with travel times lower than what we currently endure.
  • by wmajik (688431) <wmajik AT yahoo DOT com> on Sunday January 15, 2006 @01:59AM (#14474438) Homepage Journal
    You Know You Are A Geek when a /. story with the name "New Ion Engine Being Tested" makes you nearly drop the beer and wonder how a defunct game company is producing new engines.

    Nonetheless, I blame John Romero for my own confusion and/or angst, because it makes me feel better. :p
  • carpool (Score:4, Funny)

    by User 956 (568564) on Sunday January 15, 2006 @01:59AM (#14474440) Homepage
    Ion engines are a form of electric propulsion and work by accelerating a beam of positively charged particles (or ions) away from the spacecraft using an electric field.

    Cool. So can I put one on my Hummer and drive in the Carpool lane with all those Priuses?
    • So can I put one on my Hummer and drive in the Carpool lane with all those Priuses?


      Zero to sixty in 72 hours! Zoom!

    • Hybrids rarely use the electric engine while cruising on the expressway, and as such will have the same fuel economy as a comprable gasoline-only engine. Diesel cars and motorcycles use much less fuel than conventional vehicles; but not hybrids.
    • Yes, as long as your run only on the ion engine.
  • by Verloc (119412) on Sunday January 15, 2006 @02:09AM (#14474470)
    This innovation came from the addition of another grid (from TFA) used in the process of accelerating the ions. Is there any reason that they couldn't just keep adding grids with varying voltages? And why are the last two voltages both low? Wouldn't it make sense to alternate them?
    • IAN a Rocket sci. So I'm just guessing here. It might be to fine tune the focusing of the beam. The more straight it is the better.
    • by Nyeerrmm (940927) on Sunday January 15, 2006 @02:32AM (#14474547)
      Not really, what the extra grids are doing are focusing the beams more so that they actually proceed through the grid rather than hitting it. Ions hitting the grids and causing them to collapse over time is the primary failure mode for an ion thruster, so being able to focus it more seems to allow more power to be pumped into it so that the stream is accelerated faster. I guess more grids might allow you to focus it more, but I'd guess that its a diminishing returns thing. I'm doing research with these thrusters (trying to show a particular fluid simulation, which is particularly good with parallel processing, is valid), especially for the reasons the article talks about with the testing. I think im going to try this multiple grid situation and see how it acts later.
      • Why not just increase the number of ion engines? If one gives for example a 1 m/s thrust, wouldn't 20 of them combined give a 20 m/s thrust? I know its not that simple, but you will see significant increases in acceleration, I am sure. Put together a platform with 50 of them, slap on a crew compartment and storage spage, and you have your first in-system exploration ship to go gadding about in! I'd probably throw in a nuclear plant for the giant frickin lasers myself (purely to clear debris, naturally ;)),

        • by Nyeerrmm (940927)
          It's not just a question of how much thrust you get (chemical rockets are still at the top for that), its a question of specific impulse, which is basically a measure of how much propellant mass is used to attain a certain velocity change.

          A chemical rocket has a specific impulse of about 300 s-400 s, while a typical ion thruster has something closer to 3000 s. This new design should be 12,000s I guess

          Obviously for a larger mission than DS1 or this ESA probe, doubling them up to get more thrust is definitel
          • although there are limits, because each new thruster adds to the mass signficantly.

            Eh? That doesn't make sense. Yes, each thruster adds to the mass, but it makes up for that by providing additional thrust. Ideally what you want to see is a near-zero mass drive. If we can't make the ion drive fly faster, reduce the mass needed to produce it. That should pump up the acceleration curve a bit. How fast does the "ion jet" or whatever actually exit the drive anyway? Maybe it would make more sense just to buil

          • 12,000 seconds Isp? Sheesh. You may need to see a therapist about your specific impulse fetish.

            Once you get over ~3000 seconds Isp you don't really need to keep improving it. Who cares if your propellant fraction is 15% or 20% ? As long as it's not over 60% (as is often the case with chemical propulsion) you are doing fine.

            Most space probe engineers would gladly trade lower Isp for higher thrust so they don't get too old by the time the vehicle finishes accelerating. Higher *energy* efficiency would probab
    • by Lord Crc (151920) on Sunday January 15, 2006 @02:34AM (#14474552)
      Is there any reason that they couldn't just keep adding grids with varying voltages? And why are the last two voltages both low? Wouldn't it make sense to alternate them?

      If you put a high-voltage grid after a low-voltage one, the ions would be repelled by it, not attracted. The voltage gradient must go in one direction: out of the thruster. I'm no scientist, but I don't think you'd gain much by adding a third couple of grids inbetween the two with a medium-voltage level. It would probably be more fruitfull to simply increase the difference between the high and low levels.

      I assume the last two grids are low for the same reason the first two are high, to prevent errosion.
      • Tandem accelerators (Score:3, Interesting)

        by jd (1658)
        The technique is used in tandem accelerators. You have a grid that is negatively charged (so it attracts the ions) immediately prior to the grid that is positively charged (that repels the ions, once they are through the negatively-charged grid).

        Whether this is efficient to do depends on the speed of the ions. As the velocity of the ions increases, the mass increases and therefore the energy required to achieve the same level of acceleration also increases. Of course, the grids have mass, as does the energy

        • The technique is used in tandem accelerators. You have a grid that is negatively charged (so it attracts the ions) immediately prior to the grid that is positively charged (that repels the ions, once they are through the negatively-charged grid).

          Wouldn't the ions be decelerated by the positive grid? After all, the grids can't be too close (this [rrc.mb.ca] page mentions 1cm separation between the contacts in a 15kV vacuum circuit breaker).

          The references [wikipedia.org] I found [ksu.edu] mentions a different approach. Negative ions are attracted
  • by Tsar (536185) on Sunday January 15, 2006 @02:10AM (#14474472) Homepage Journal
    The test model achieved voltage differences as high as 30kV and produced an ion exhaust plume that travelled at 210,000 m/s, over four times faster than state-of-the-art ion engine designs achieve. This makes it four times more fuel efficient, and also enables an engine design which is many times more compact than present thrusters, allowing the design to be scaled up in size to operate at high power and thrust.

    Since KE=(mv^2)/2, wouldn't an ion engine with over four times the exhaust velocity have over 16 times the efficiency, all other factors being equal? And wouldn't an increase in ion KE produce a proportional increase in the erosion rate of the dual low-voltage grids, along with a concomitant shortening of the engine's usable service life?
    • YANAP... (Score:5, Informative)

      by ArcSecond (534786) on Sunday January 15, 2006 @02:14AM (#14474485)
      Think momentum, not energy.
      • I think the use of the word "fuel" is just downright confusing, since although the stuff being referred to is expended during acceleration, it is not itself providing any actual energy. It is just arbitrary junk being thrown off the back of the spaceship to speed it up (ala Newton's 3rd law), with the potential difference presumably coming from some other energy-producing substance that should more accurately be referred to as the fuel.
    • In the conservation of momentum equations the impulse is m.v, So for four times the velocity gives you have four times the impulse, for a given mass of gas expelled.
      • Alternatively, to get the same momentum, you only need to send out 1/4 of the mass. Of course you need 4 times the energy to accelerate the ions (4 times the speed gives a factor of 4^2=16 for the energy, but 1/4 of the mass gives just the factor 1/4; or said differently, with E=p^2/2m, using 1/4 of the mass for the same momentum gives 4 times the energy). So while this new drive is more propellant efficient, it also is more energy hungry. OTOH, when looking at a real space probe, you'll also have to accele
  • Finally... (Score:5, Funny)

    by RobTheJedi (547899) on Sunday January 15, 2006 @02:11AM (#14474474)
    One step closer to my TIE Fighter.
  • ...the one described in this earlier slashdot story [slashdot.org]? If so, it looks like they've progressed from concept to prototype.
  • by nurhussein (864532) on Sunday January 15, 2006 @02:20AM (#14474507) Homepage
    That's neat! Now if we could hook up two of these babies together, and perhaps add solar panels for additional power, we'd get space craft with twin ion engines. Hrm. Twin ion engines... where have I seen that [starwars.com] before?
  • by imstanny (722685) on Sunday January 15, 2006 @02:41AM (#14474576)
    The real question is; do the Europeans have a 'Flux Capacitor'?
  • Dumb health question (Score:3, Interesting)

    by Jeremi (14640) on Sunday January 15, 2006 @05:15AM (#14474884) Homepage
    Okay, here's a dumb question for you: I've got a pretty good idea what would happen to me if I stood right behind a traditional rocket while it was lit. But what would happen to me if I stood right behind one of these while it was running? Instant death? Intense pain? A refreshing tingly sensation?
    • Not so dumb. (Score:5, Interesting)

      by imsabbel (611519) on Sunday January 15, 2006 @06:29AM (#14475046)
      Well... on earth, nothing would happen, as this kind of engine only works in vaccuum... The mean free travel lenght of those ions in air would be meassured in mircrometers...

      In vaccuum, you would die rather violently, due to shortage of air....

      So i dont think this is a practical concern...

      Of course, if you were in a spacesuit, there would be an issue...

      The process (hitting an object with high energy noble gas ions) is also used on earth, where to precess is used to alter surfaces of materials. Its called "sputtering", or "plasma etching". So i guess you can get a general idea of what it does... It cant penetrate your spacesuit, but will happily kick layer by layer of atoms from its surface.

      If you waited long enough, it would open holes/ect, but it you be very damaging to sensor equipment/solar cells even with short exposures.

      Think of a very low power slaver desintegrator from the ringworld novels :D
  • by sanman2 (928866)
    I realize these ion engines have a low thrust/acceleration as a tradeoff against their better fuel economy, which means they're really meant for the long-duration missions such as to the outer planets, etc. Yet I wonder if this new ion thruster design, and also the Double Layer Helicon Thruster that was also recently tested, will result in ion engines that could take man to Mars?

    It would be nice if upcoming unmanned space missions could put these new ion engines through their paces, to see how much performa
  • .... now there's an idea with potential...
  • Does anyone know how these engines avoid accumulating a net charge over time? If you're emitting a stream of positive ions for a long time, and you're not taking in any negative ions, you would have an increasingly large negative charge. It seems that this would decrease the thrust over time, not to mention electrocuting the vessel upon re-entering an atmosphere.

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