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Space Science

Ion Engine Propels Probe to Moon 330

lenin writes "The BBC is reporting that Europe's first moon mission, SMART-1, appears to be a success thus far. It also talks about the low-cost technology being used and the charged xenon (ion) propulsion system. Can TIE-fighters be far off?"
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Ion Engine Propels Probe to Moon

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  • by panurge ( 573432 ) on Sunday September 28, 2003 @02:47PM (#7078906)
    If Tie fighters had the acceleration of the Smart-1, Lucas Skywalker would have had nothing to fear. There's obviously some sort of competition on for the slowest flight to the Moon. The acceleration is even lower than that of the Smart car [].

    Yes, I do know why ion engines are a good idea. Just leave Star Wars out of this.

  • TIE (Score:5, Funny)

    by CGP314 ( 672613 ) <CGP AT ColinGregoryPalmer DOT net> on Sunday September 28, 2003 @02:50PM (#7078938) Homepage
    It also talks about the low-cost technology being used and the charged xenon (ion) propulsion system. Can TIE-fighters be far off?

    Yup, that's how technology goes, straight from moon probe to TIE fighters. No intermediate steps necessary. No life support, no radiation shielding, necessary. I can't wait to buy my A-Wing.
    • Not to be an over-obsessed SW geek, but the TIE fighter didn't have a life support system. That's why the pilots needed those air masks, while the X-wing pilots got the open-air helmets.

      • Not to be an over-obsessed reality geek, but even the Space Shuttle had life support in addition to the pressure suites they wear on take off and landing. The suits are in case of sudden decompression.

        In Soviet Russia, early cosmonauts didn't wear pressure suites to display the superiority of their space program. They needlessly lost people due to that practice, and have changed to using pressure suites as result.

        Also, remember the TIE figter pilots were clones, so they would wear a mask even if they we
    • Not to mention particle weapons. Or force fields and faster-than-light travel. (for your A-Wing, yes, I know TIE fighters are unshielded and sublight)
    • Re:TIE (Score:5, Funny)

      by gl4ss ( 559668 ) on Sunday September 28, 2003 @03:11PM (#7079098) Homepage Journal
      dude, tie fighters don't have life support(the pilot needs a full space suit)! that's why they're so cheap at your local imperial clearing sales.

      geez, the people on slashdot these days!
    • I am going to buy this technology and use it to dessimate that pesky web slinger once and for all!!!!

      We don't need no stinkin' micro-meteor deflection systems, no how! :)
    • Re:TIE (Score:3, Funny)

      by ScottForbes ( 528679 )
      I find your lack of faith... disturbing.
  • by Limburgher ( 523006 ) on Sunday September 28, 2003 @02:51PM (#7078942) Homepage Journal
    "But Ion engines can never acheive fast accelleration"

    (sigh) Then the Emperor has already won.

  • Sure the Ion drive is a really neat addition, but it's soooo slooooow. It's going to take them 15 MONTHS to get there! And the payload isn't really greater at all. It takes longer to get any large loads going. The US space program got people to the moon and back in what...2 weeks? It may be slightly more economical, but it just doesn't seem practical.
    Hopefully they can perfect the ion drive, however through this to increase the speed and payload capacity. Then we might have something really cool... (u
    • What's the hurry? The moon will keep. Think science, not Star Wars.
    • by adeyadey ( 678765 ) on Sunday September 28, 2003 @03:36PM (#7079254) Journal
      This is really a test bed for the ion-drive technology - although even on this mission, its effective to do it this way, once in lunar orbit the drive can make slow adjustments to cover the whole surface, without having to carry huge amounts of propellant. Over LONG periods of operation, the ion drive is something like 10 times more effective in terms of fuel carried vs thrust given compared to chemical rockets - and that figure is set to improve as research progresses. SMART-1 is an important step in that research. The Ariane-5 launch rocket is a fraction of the size/cost of the Apollo/Saturn-5's..

      In the future missions you will see these sorts of drives giving much faster flight times to Mercury, Mars, Jupiter, Saturn.. - although for the outer system you may need nuclear instead of solar power.

      Yes both this and parent are dupes from previous thread..
    • by Clueless Moron ( 548336 ) on Sunday September 28, 2003 @04:06PM (#7079406)
      slightly more economical???

      This project cost just 100E6 Euros. That's about one quarter the cost of a single shuttle launch, never mind the astronomical costs of each Apollo mission.

      Personally I'd much rather see 4 new projects like this and one fewer shuttle launch.

    • Smart is solar powered, and likely on the order of 1's or 10's of kilowatts.

      Once you start tying ion propulsion to a nuclear power source, you start being able to achieve higher thrust levels. SMART only uses a little over 1kW of power.

      Its very practical.
      Ion propulsion can take longer than chemical (although this is not always the case) but it has a much higher specific impulse, and therefore a much lower propellant mass fraction. That means you can get more mass to a destination given the same launch m
  • elevator (Score:5, Funny)

    by spectrokid ( 660550 ) on Sunday September 28, 2003 @02:52PM (#7078950) Homepage
    If we combine this with the space elevator, we can send shit to the moon on 6 AA batteries!!!
  • anyone else wondering where such a small system is getting the energy needed to ionize a large amount of xenon atoms?
    • Actually, no big mystery, it has enormous solar panels 10s of meters long.
    • The concept relies on using power from the solar cells to make the force. This is opposed to carrying fuel.

      Using this system only a very small amount of mass is needed to accelerate the craft to quite high velocities, because the energy isn't lifted from the gound but produced in orbit.

      On a normal probe the energy for popultion would reside in the fuel carried in tanks, here it resides in the rather large fusion reactor at the center of the solar system.
  • by Tumbleweed ( 3706 ) on Sunday September 28, 2003 @02:58PM (#7079002)
    TO THE MOON!!!
  • Friction (Score:4, Insightful)

    by RetroGeek ( 206522 ) on Sunday September 28, 2003 @03:01PM (#7079021) Homepage
    Can TIE-fighters be far off?

    There will be no TIE fighters until we have friction in space. To be able to turn like an airplane in an atmosphere you need something to react against.
    • Wrong.

      You just need to have enough mass you can eject in some direction. That is called propulsion. Just collect enough light, and you will be doing well.
    • Not at all, you just need to generate massive thrust in arbitrary directions. The easy way to do this is generate thrust out the back and then have a thruster at the front-top, front-bottom, front-left, and front-right that allow the vehicle to spin on its center.
    • to the galaxy. Obviously this maneuver is very unnatural for all space vehicles, but it looks so cool rich people will surely want to have stuff that does that implemented in their spaceships. Just for showoff, no matter how inefficient and ridiculous that would seem :)
    • Not necessarily.

      What if someone invented a 'Gravity reflector' that replys gravity? then you could us the gravity as the force your reacting to in order to move like an aircraft.

      Sure, It sounds lame from me on slashdot, but if any greate Sci-Fi author had the same idea, you would think it was the coolest idea since cat doors.
  • Although, Ion's second time around are just as fun!

    Yo Grark
    Canadian Bred with American Buttering...American Buttering....American Buttering...
  • by Anonymous Coward on Sunday September 28, 2003 @03:07PM (#7079066)
    We like the moon
    Coz it is close to us
    We like the moon
    But not as much as a spoon
    Cos that's more use for eating soup
    And a fork isn't very useful for that
    Unless it has got many vegetables
    And then you might be better off with a chopstick

    Unlike the moon
    It is up in the sky
    It's up there very high
    But not as high as maybe
    Dirigibles or zeppelins or light bulbs
    And maybe clouds
    And puffins also I think maybe they go quite high too
    Maybe not as high as the moon
    Coz the moon is very high

    We like the moon
    The moon is very useful everyone
    Everybody like the moon
    Because it light up the sky at night
    And it lovely
    And it makes the tide go
    And we like it

    But not as much as cheese
    We really like cheese we like zeppelins
    We really like them and we like kelp and we like moose
    and we like deer and we like marmots
    and we like all the fluffy animals
    We really like the moon
  • by be-fan ( 61476 ) on Sunday September 28, 2003 @03:07PM (#7079072)
    Check out this page [] for some nifty things you can build that may work on ion-propulsion. I thought it was a hoax at first, but my friend convinced me to build it in high-school, and the thing really did work. Of course, the efficiency was terrible. We were using an old monitor as a 20,000 volt power source, so power dissipation was probably pretty high. That was enough to lift the 2 gram device and 1 gram of payload.
  • Are we going to get daily news on this project? []
  • by Anonymous Coward
    ...probe Uranus?
  • by dpilot ( 134227 ) on Sunday September 28, 2003 @03:31PM (#7079217) Homepage Journal
    This one is more reputable, I believe credited to Arthur C. Clarke.

    It was a short story about an Earth-to-Moon (orbit-to-orbit) space race, in the spirit of the Kremer prize. The spacecraft were propelled by ion engines, which were energized by Whimshurst-type machines, which were powered by ...


    The racers pedaled their way to the moon, the pedals effectively powering the ion engines that drove them. The race took several days, with the right stuff added in for absurd athletics, rest breaks, minimal life-support, race security, etc.

    No doubt someone here will do the math that I never bothered trying to do. One of these days, maybe I will.
    • No doubt someone here will do the math that I never bothered trying to do.

      I ran some numbers and the feasibility depends pretty much entirely on the weght of the spacecraft.

      If we assume a 250,000 mile race, completed in 10 days, (with no resting, since that complicates things more than I want to deal with right now), that means you need a constant acceleration of 0.11 cm/s^2. Not very much, right? Not if you're just accelerating your own weight. In fact, if *all* you had to push was, say, 60kg, it'd

  • by adeyadey ( 678765 ) on Sunday September 28, 2003 @03:32PM (#7079221) Journal
    Sorry for that pun, but..

    One point worth making - chemical rockets are getting close to the limits of thier possible efficiency. In contrast Ion engines are in their infancy. The main theoretic limit is that particles cannot be expelled faster than light. You could see very big leaps in engine power in the future..
    • In what way do you consider the fact that particles cannot be expelled faster than the speed of light a "limit"? As (almost) always when relativistic speeds are involved, think in terms of momenta instead of velocities... (the momentum of a particle is unbounded)
      • it's a limit because the maximum velocity for a space craft is the velocity with which it ejects its fuel. Ion engines are faster than chemical engines because the xenon is highly accelerated. The acceleration of the ion propelled space craft is (currently) low, because the thrust of an engine is proportional to the mass of expelled fuel. When ion engines become mature, it will be possible to expel more ions and then you wont need to have a one year acceleration phase before the actual mission can start. So
        • it's a limit because the maximum velocity for a space craft is the velocity with which it ejects its fuel.

          No, it isn't. You just have to carry more fuel if you want to exceed your exhaust velocity. This is basic physics. Review the rocket equation. Current rockets routinely exceed their exhaust velocity by several times. (NB - this applies to rockets carrying -- and hence accelerating -- their fuel. A scramjet has a problem with this -- which is why scramjets are really a silly idea for Earth-to-orbi
  • Ion Propulsion (Score:5, Informative)

    by Listen Up ( 107011 ) on Sunday September 28, 2003 @03:37PM (#7079266)
    I spent a lot of time studying this technology while I was working towards my Bachelor's Degree. Okay, let's get some facts straight, for those of you without a degree in Mathematics or Physics:

    1) Ion Propulsion is NOT new technology. The Russians and German's have been experimenting with Ion Propulsion since the early 1950's. NASA is actually a late comer to the game, although the first with a completed ion propulsion engine.

    2) Ion Propulsion do not work in an environment with an atmosphere. An ion engine does not have enough force to lift a sheet of paper more than a few inches.

    3) An Ion Engine is very simple in design. For a simple explanation, an inert gas is ionized and injected into a chamber with an opening on one end. The opening has a magnetized torid ring around it. Using the right hand rule (make a fist, stick your thumb out like you are hitchhiking...your thumb is the direction of the electric current, your fingers are curled in the direction of magnetic field flow) you create an electrical flow around the metal torid ring. The resulting magnetic field 'pulls' the ions through the ring, resulting in propulsion.

    4) The reason for slow inital acceleration is because the force of the ions passing through the ring is very small, but the velocity of the ions is very high. So, since there is no friction or other losses in space, after a period of time the velocity of the ions leaving the ring increases the velocity of the engine. After a matter of days the engine can be travelling at 10-30,000MPH.

    For more information and history on Ion Propulsion engines you can go to the following websites: ap r99_2.htm ar /
    • ion propulsion works just fine in an atmosphere, unless im misunderstanding the working of the popular 'Ionic Breeze' air filters.
    • Re:Ion Propulsion (Score:5, Informative)

      by jd ( 1658 ) <imipak AT yahoo DOT com> on Sunday September 28, 2003 @04:20PM (#7079514) Homepage Journal
      Two small notes:

      First, this probe was from the European Space Agency, not NASA. NASA doesn't own Europe, as far as I know, and can't even afford to replace the bearings on the ancient platforms that carry the Space Shuttles to the launch pad.

      Second, NASA's Ion engine (on Deep Space 1) failed in lab tests, and then failed in space. NASA had to "shake" the probe using the gas-based manoevering jets, using up valuable fuel. The probe was a success in the end, but more by luck than design.

      • by brocheck ( 59415 ) <brocheck.satlug@org> on Sunday September 28, 2003 @04:44PM (#7079680) Homepage
        Where-ever it is you live I imagine our glorious country is not far from demonstrating quite plainly where it is we've spent the money that was once sent to NASA for the foolish exploration of space (we already discovered there is no oil there). We may not have space-craft built in the last twenty years but what we do have speaks for itself: GPS guided smart-bombs, and a lot of them!

        Don't worry, citizen, soon we'll liberate you too!
    • Re:Ion Propulsion (Score:4, Informative)

      by Manhigh ( 148034 ) on Sunday September 28, 2003 @06:17PM (#7080296)
      The opening has a magnetized torid ring around it. Using the right hand rule (make a fist, stick your thumb out like you are hitchhiking...your thumb is the direction of the electric current, your fingers are curled in the direction of magnetic field flow) you create an electrical flow around the metal torid ring. The resulting magnetic field 'pulls' the ions through the ring, resulting in propulsion.

      Actually, what you describe there sounds like a Hall effect thruster. Not all ion drives are Hall thrusters.

      DS1's ion engine used charged grids rather than a metal toroid to achieve the acceleration of the ions.

      In addition to Hall effect thrusters and grid-based ion engines, there are also arcjets, resistojets, and the ever-sexy-but-a-few-years-off magneto-plasma-dynamic thrusters.
  • Tuesday is when the ion drive gets switched on for the first time.
  • Re: Friction (Score:5, Interesting)

    by shoemakc ( 448730 ) on Sunday September 28, 2003 @04:05PM (#7079397) Homepage

    There will be no TIE fighters until we have friction in space. To be able to turn like an airplane in an atmosphere you need something to react against.

    AFAIK, space isn't a perfect vacuum, there is matter in space, just that it's concentrations are extraordinarily low. You'd need either a very large control surface, or some method of increasing friction over what limited matter there is. Why do we use brake pads on a car and not say, bars of moist Ivory? Same reason.

    Also, there is also free energy in space...particularly in a solar system. I'm not sure if light energy is believed to be particulate this week, but is it possible that photons or other forms of high frequenty energy could be used as a repuslive force? There's still quite a bit we don't understand about this stuff, and though at this point it's still probably the rhelm of science fiction, It's not impossible. Remember, there are no fictionless surfaces, no perfect vacuums, no perfect superconductors, only asymptoticly approaching approximations.


    PS - I apologize in advance for the above average number of typos and possible flaws in knowledge and logic....I'm on an iMac today ;-)

    • by rd4tech ( 711615 )
      The mathemaician said: It won't be zero value, lets run few more pages of equations. The physicist said: We can safely assume it is orbiting zero value in this equation and thus reduce the next few pages. The engineer said: Screw it, it's zero. Lets build the damn thing.
    • on the TIE fighters were solar panels - that's why the TIEs were "short range fighters".
  • Xenon sucks (Score:5, Funny)

    by Waffle Iron ( 339739 ) on Sunday September 28, 2003 @04:17PM (#7079485)
    It also talks about the low-cost technology being used and the charged xenon (ion) propulsion system.

    I hate those self-important A-holes who have those xenon propulsion systems. It seems like every night that I go for a short trip in low earth orbit, at least one schmuck has to fly by with those damned things turned on. How am I supposed to see where I'm going when I'm being blinded by the obnoxious blue glare that they spew? If they're the only ones who can see anything, it's not making things any safer overall.

    I swear, I'm going to start flashing these jokers with my laser range finder if they don't get more considerate and stop using those damned xenon units in congested orbits.

  • thoughts (Score:4, Interesting)

    by itzdandy ( 183397 ) < minus threevowels> on Sunday September 28, 2003 @04:29PM (#7079582) Homepage
    if your '71 chevy truck is slow, you just put in a bigger engine right?! so how about a bigger ION drive. and a small nucleur reactor.

    i suppose you do lose some efficiency by carrying your own fuel, but nuclear power is far more efficient than solar power right now.

    with larger ION drives, or more small ION drives, and enough power from the reactor, this may be able to compete with a rocket engine for inter-solarsystem travel.

    but then again, id rather have laser,mazer, or phaser cannons. I'll travel really really slowly if I have a really big gun!


    another advantage would be less vibration during accelleration. Imageing sending a team to Alpha Centauri using standard rockets. They would have to burn for 3 solid months to accellerate and the same to decellerate. 3 months is a long time to be strapped to a chair.

    this solves the lack of gravity problem as well. Just accellerate at a rate the would be near 1G or at some acceptable level of force, then spin the ship around and do the same thing for decelleration. This way you would have artificial gravity for a good portion of the trip. I can't imagine the side effects of a couple of years is zero G, and what happens when the team trys to go to the plannet with no muscles built up for planetside life.

    Alpha Centauri is something like 5,644,944,000 kilometers away, this is most likely a 5-10 year trip. Yes, artificial gravity would be good.

    Also, the waste material from the reactor could be used as the actualy propellant(maybee, IANORS(I am Not a Rocket Scientist) and then you wouldn't have to store it, you could just eject it out the back of the craft.
    • Re:thoughts (Score:4, Informative)

      by ninthwave ( 150430 ) <> on Sunday September 28, 2003 @05:11PM (#7079880) Homepage
      ok Alpha Centauri is a star system consists of Alpha Centauri A, Alpha Centauri B and Proxima Centauri, that appears as a single star to the naked eye. Of that system we are closest to Proxima Centauri not Alpha Centauri. The distance to Proxima Centauri is 4.36 light years.
      In Kilometers this is:

      So you calculation is a bit off in the time scale.
      To reach it in 10 years you would have to be going roughly half the speed of light or 150,000,000 meters per second
  • by thepacketmaster ( 574632 ) on Sunday September 28, 2003 @04:48PM (#7079707) Homepage Journal
    This isn't the first time an ion engine has been used in space. NASA's Deep Space 1 [] probe toured the solar system for over 3 years with an ion engine. This probe isn't very well known, since it was just a test bed. But in the end it made some history by performing the closest encounter ever with a comet.
  • It should be noted that the world has sent only a tiny set of probes to the Moon in the last 30 years - and only one of them (Lunar Prospector) was a NASA mission. The other US mission (Clementine) was also a very small and inexpensive mission, so basically since Apollo ended our spending on actual lunar missions has been maybe 2% what we've spent on Mars. Does that make sense to anybody here?

    NASA still seems very reluctant to send anything, but they are being forced to by a recent review of solar system p
  • Remember it was a LONG time ago, in a galaxy FAR FAR AWAY.
  • It may help to think of any rocket-type (and ion, too) propulsion based system like this:

    Basically, the center of mass of a fueled up rocket does not change. If you had a rocket at a dead stop and started a burn, you'd throw as much stuff behind you as your displacement was forward. Hence in a simplified 1D rocket model (which is actually pretty close to correct, diffusion is actually pretty minimal) your center of mass never moves.

    Arguably, you could say this means that the entire rocket array (fuel an

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