Please create an account to participate in the Slashdot moderation system

 



Forgot your password?
typodupeerror
×
Space Technology Science

Plasma Rocket Successful Full Power Test 169

Matt_dk writes "VASIMR is a new high-power plasma-based space propulsion technology, initially studied by NASA and now being developed privately by Ad Astra. A VASIMR engine could maneuver payloads in space far more efficiently and with much less propellant than today's chemical rockets. Ultimately, VASIMR engines could also greatly shorten robotic and human transit times for missions to Mars and beyond."
This discussion has been archived. No new comments can be posted.

Plasma Rocket Successful Full Power Test

Comments Filter:
  • by TheRealZero ( 907390 ) on Monday October 27, 2008 @02:10PM (#25531623)
    LCD rockets have sharper colors.
  • by mcgrew ( 92797 ) * on Monday October 27, 2008 @02:10PM (#25531631) Homepage Journal

    The VASIMR engine works with plasma, a very hot gas at temperatures close to the interior of the Sun. Plasmas are electrically charged fluids that can be heated to extreme temperatures by radio waves and controlled and guided by strong magnetic fields. The magnetic field also insulates any nearby structure; so temperatures well beyond the melting point of materials can be achieved and the resulting plasma can be harnessed to produce propulsion. In rocket propulsion, the higher the temperature of the exhaust gases, the higher their velocity and hence the higher their fuel efficiency. Plasma rockets feature exhaust velocities far above those achievable by their chemical cousins, so their fuel consumption is extremely low and their fuel-related costs substantially reduced.

  • Constant Boost? (Score:5, Interesting)

    by Fished ( 574624 ) <amphigory@@@gmail...com> on Monday October 27, 2008 @02:12PM (#25531671)
    I couldn't find an answer in the article, or on the Wikipedia page... are the "reduced reaction mass" requirements for this engine such that constant boost becomes a possibility for longish missions? If so, then this effectively puts the Solar System within reach.
    • Re:Constant Boost? (Score:5, Insightful)

      by Kjella ( 173770 ) on Monday October 27, 2008 @02:30PM (#25531905) Homepage

      In theory, we could always do that, in practise I don't think we'll ever do that. Getting anywhere really fast burns a ton of extra energy, plasma drive or not. Most of the really long-distance missions haven't accelerated to that speed, they've done a slingshot trip around jupiter or something like that. Even on a Mars mission we're really just waiting for Mars to be in the right position to leap orbit and minimize the rocket use, not plotting a course or going from full impulse to full stop in seconds like you see on Star Trek. It would still cut a lot of costs but the cheapest route is still the slow one.

      • Re: (Score:3, Funny)

        {STAR TREK FANBOY}

        You can't go full impulse to full stop in seconds without inertial damping anyway. Duh.

        {/STAR TREK FANBOY}
      • by ceoyoyo ( 59147 )

        You're assuming (as most likely the grandparent did) that constant boost means HIGH constant boost (like 1 G).

        We've launched a few ion engine powered ships that employ more or less constant boost. The acceleration is very small, but it adds up over time.

        Getting somewhere really fast takes extra propellant, but you have to burn a certain amount to get there at all. Constant boost just means you burn it slowly, as you go, rather than burning it all in a few seconds or minutes and then coasting the rest of t

    • Re:Constant Boost? (Score:5, Informative)

      by jollyreaper ( 513215 ) on Monday October 27, 2008 @02:33PM (#25531947)

      Typically these rockets are more efficient than their chemical cousins. For a given reactant mass, rockets will give you more thrust (can't get into orbit with anything but rockets at this point) but the plasma and ion engines are more efficient, low-thrust but higher change in velocity (delta-v.)

      As it was described, a mars mission using an ion engine would not leave the space station with a dramatic blast of flame. The captain would say "turn the engine on," go, get coffee, watch a movie, look out the window and still be able to wave back to people at the station. Tune back in three weeks later and he'll be moving at a clip that would make chemical rockets weep in jealousy.

      • Sounds like the smart move would be to combine the systems to get the best of both worlds (some sort of chemical/plasma/ion transmission system)

        • Regarding your sig:
          'Can someone explain to me why the () go inside the period, but the "" go outside the period?'

          They don't. Correct (but old-fashioned) English usage has them both have the . inside the () or "". Modern usage, especially among science type, is to have the . outside any parenthesis, to keep the base sentence internally consistent (and other logical reasons).

          Your perception stems from the way science types use () more often than "", and older English teachers use "" more often than ().

          • Regarding your sig:
            'Can someone explain to me why the () go inside the period, but the "" go outside the period?'

            you just did it there. Why is the ? inside the quotes? Because it's part of my question? Should'nt it then be

            you asked 'Can someone explain to me why the () go inside the period, but the "" go outside the period?'.

            See what I mean? I'm not trying to be trite, I am honestly confused. If I quote the word time and say I need more "time", why is that incorrect?

            • In the case you mention, the ? belongs to your quote; thus, I include it in the ''. The following example illustrates the other case:

              What did you mean when you said 'that idea is poison'?

              In the preceding sentence, the ? is outside the '' because the question belongs to the speakers words, not to the quote he is using.

              In all honesty, the real reason in this case was I was too lazy to type out the <blockquote> </blockquote> tags, instead I just used the ' '.
      • Re: (Score:3, Informative)

        by doug ( 926 )

        If it launched from a station in orbit, it will need to accelerate from 5mps to 7mps to break orbit. Does this slow acceleration imply that VASIMR power ships will have to circle the earth a few times to build up speed?

        • Yeah. Check out this conceptual video [youtube.com] they put up for a possible Mars mission with 3 VASIMR engines.

          • Sounds like a small-ish booster stage to break orbit, and keep going with the VASIMR would be a useful idea, so far as absolute time goes. I doubt it would be worth the extra effort, though.

      • Not being a rocket scientist here, I thought ejection velocity was a positive benefit of plasma rockets. Since you can get high ejection velocities, you can require less mass to achieve the same final velocity. Hence, mass is not as critical compared to tradition rockets. This is great for long term missions as we have plenty of time to get upto speed (and down to speed). But for maneuvering, I think chemical ejection would be more appropriate since less time is needed to make a maneuver.

        Or for that matte

      • Typically these rockets are more efficient than their chemical cousins.

        They are more efficient on paper, but in real world engineering, not so much.

        For a given reactant mass, rockets will give you more thrust (can't get into orbit with anything but rockets at this point) but the plasma and ion engines are more efficient, low-thrust but higher change in velocity (delta-v.)

        But much of the theoretical performance gain is eaten up by the need to provide a source of power - and for any significant payloa

    • The Numbers (Score:5, Informative)

      by StefanJ ( 88986 ) on Monday October 27, 2008 @03:04PM (#25532401) Homepage Journal

      The Wikipedia entry says it can be tuned for an Isp of 3,000k seconds to 30,000k seconds.

      A liquid fueled chemical rocket has an Isp of about 500 seconds. A really good fission thermal rocket, maybe 1000 seconds. The Deep Space 1 ion rocket could do 3.1k seconds.

      How to turn this into usable numbers:

      Find the exhaust velocity. Vex. Multiply the Isp by "g". So, your chemical rocket has an exhaust velocity of about 5 kps, and your VASIMIR 30 kps.

      The figure out the velocity change you want. Vd.

      Then:

      M(o)/(M(o)+M(f)) = e^(Vd/Vex)

      M(o) = Mass of spaceship without reaction mass
      M(f) = Mass of reaction mass
      e = natural log number, about 2.178

      A Hohmann orbit trip to Mars orbit from Earth orbit without need for aerobreaking of the like might require 20 kps. Hohmann orbit to Mercury, 40 kps.

      Drawback to ion drives and VASIMIR is a really, really low thrust. You might be better off with lower efficiency but higher thrust or you'll lose the fuel (uh, reaction mass) savings in consumables, and/or risks to your crew from flares.

      • Re:The Numbers (Score:4, Informative)

        by ceoyoyo ( 59147 ) on Monday October 27, 2008 @04:17PM (#25533501)

        Your VASIMR ISP figures are out by 1000. It's 3000 to 30000 seconds, or 3 to 30 k seconds, NOT 3000 to 30000 k seconds.

        Generally, if you're going a decent distance, you SAVE time with a high ISP engine, even if it is low thrust. "Decent distance" depends on the specifics, but for most of these engines Mars is far enough away, the moon, probably not.

        • See what happens when you post with a low-grade fever?

          I managed to post the Isp without the extraneous "k"s down the page a bit.

      • by Fzz ( 153115 )
        M(o)/(M(o)+M(f)) = e^(Vd/Vex)

        M(o) = Mass of spaceship without reaction mass
        M(f) = Mass of reaction mass
        e = natural log number, about 2.178

        Are you sure you got the mass ratio the right way up?
        M(o)/(M(o)+M(f)) is fractional, but e^(Vd/Vex) is greater than one for positive Vd, Vex, so this can't work.

    • by ceoyoyo ( 59147 )

      Certainly. You'd probably want to use one of these things at pretty much constant boost.

      Now, that doesn't mean 1 G.

  • The VASIMR engine works with plasma, a very hot gas at temperatures close to the interior of the Sun. Plasmas are electrically charged fluids that can be heated to extreme temperatures by radio waves and controlled and guided by strong magnetic fields. The magnetic field also insulates any nearby structure; so temperatures well beyond the melting point of materials can be achieved and the resulting plasma can be harnessed to produce propulsion.

    Anyone know if this could be used in fusion reactor containment?

    • Re: (Score:3, Interesting)

      That's what they do. The problem is that when you're doing a fusion reactor, you need to have positive energy yields. With a plasma engine, you just need to be able to propel yourself. So in the short term, I doubt anything will come of this.

      However, in the long term, this could be key to getting workable fusion reactors. If the technology for a plasma engine becomes widespread with several independent firms working on it, it's entirely possible that a big breakthrough for fusion reactors will come from
      • Even indirect help. Those higher efficiency containment fields would end up making fusion research cheaper to perform, correct?

    • Yup, [wikipedia.org] as planned for ITER [wikipedia.org].

      Thanks, Andrei [wikipedia.org]

  • by Cyclopedian ( 163375 ) on Monday October 27, 2008 @02:17PM (#25531745) Journal

    Preferbly General Products #2 with a statis field.

    • Re: (Score:3, Funny)

      by Qzukk ( 229616 )

      a statis field.

      While I applaud finding a use for the whole lot of them, I'm not sure just what kind of protection you'd get from strapping a bunch of Big Government democrats and republicans to your hull... oh wait, you meant stasis not statist ;)

      • by R2.0 ( 532027 )

        "I'm not sure just what kind of protection you'd get from strapping a bunch of Big Government democrats and republicans to your hull..."

        Well, they aren't that great at meteor or radiation protection, but they are cheap, there's a lot of them, and no one will really miss them.

        And the drumming of their feet on the hull as they suffocate is very relaxing.

      • by treeves ( 963993 )
        I'm sure a field of statice would be very pretty, but not much good as a spacecraft hull.
    • by Coraon ( 1080675 )
      Don't forget to add a few on the front of the ship as well, less you forget the The Kzinti Lesson: http://www.projectrho.com/rocket/rocket3x.html [projectrho.com]
  • by Anonymous Coward

    ...whether this technology is more like Windows or Linux before I can form an opinion.

    Unless there's an RIAA angle, of course.

  • This is all fine with regards to the rocket equation, but that's just about conservation of momentum. You still have to provide it with energy, and 2*H2+O2 -> 2*H2O happens to be as good as you can get in terms of energy/mass ratio. As I see it, this plasma rocket is not really useful without a nuclear power source of some kind.

    • by bornyesterday ( 888994 ) on Monday October 27, 2008 @02:41PM (#25532059) Homepage
      no fusion is involved here. they ionize hydrogen gas and turn it into a plasma and then heat it even further by applying radio waves (i.e. they basically put it in the microwave) and then they let the plasma out through a ring of magnets which focus and accelerate the exhaust. there isn't much in the way of specific data regarding this, but i don't think that the amount of energy needed to create radio waves or to ionize the hydrogen gas is really that great. the majority of the acceleration force is inherent in the energy of the particles since they are at over 100 million degrees F and that force is then amplified by magnets which themselves likely require little to no electrical power
      • by ceoyoyo ( 59147 )

        ALL of the acceleration energy comes from heating (via the radio waves) and accelerating (via the magnets). It takes a considerable amount of energy. Slightly more than you get in the kinetic energy of your spacecraft, actually.

    • by mshannon78660 ( 1030880 ) on Monday October 27, 2008 @02:47PM (#25532141)
      As I see it, this plasma rocket is not really useful without a nuclear power source of some kind.

      I think they've already solved that one.

      SNAP [wikipedia.org]

      RTG [wikipedia.org]

      Nuclear Reactors for Space [world-nuclear.org]

      • Re: (Score:3, Interesting)

        by rrohbeck ( 944847 )

        Only nuclear reactors. RTGs deliver too little power. A Polywell would be nice if it woks.

    • Re: (Score:2, Funny)

      by edrobinson ( 976396 )
      DiLithium crystals should suffice as a fuel.
    • As I see it, this plasma rocket is not really useful without a nuclear power source of some kind.

      There's a fine, time-proven, continuous fusion reactor about 93 megamiles away from Earth, complete with a power beam system sending plenty of power out this way. They call it "the sun".

      At this distance it provides over a kilowatt per square yard of receiver surface area. In orbit (or at feather-light acceleration) the collection structures can be very low mass. So even something with pretty low efficiency an

    • by vlm ( 69642 )

      As I see it, this plasma rocket is not really useful without a nuclear power source of some kind.

      Solar would work quite well, especially on a trip to the inner solar system (mercury / venus)

      I think it would be wiser to head inbound for manned missions... easier to keep warm and vastly higher solar output levels.

  • The article didn't mention is, so I'll ask the crowd: does anyone know what the specific impulse [wikipedia.org] of this device would be when completed?

    • by StefanJ ( 88986 ) on Monday October 27, 2008 @02:51PM (#25532195) Homepage Journal

      The same incorporates "variable specific impulse" so you have to use a range.

      3,000 seconds is comparable to a ion motor.

      30,000 seconds is better than the predicted Isp of the Orion nuke-bomb drive.

    • Re: (Score:2, Informative)

      by Anonymous Coward
      Ad Astra hasn't put up a whole lot of detailed information on their website (I assume they're busy doing engineering and test work...PR can come later), but wikipedia gives [wikipedia.org] an unsourced number of 3000 to 30,000 seconds, presumably depending on the settings of the engine since one of the touted advantages of VASIMR is the ability to switch between "high" thrust or high efficiency settings for the same size power supply. 3000 seconds is on par with existing ion engines, and slightly below other under developm
      • Efficiency is an area where ion rockets excel, but power is where chemical rockets excel. The first stage of the Saturn V actually burned propellent at a rate of about 190,000 MW, which is equivalent to nearly 200 commercial nuclear power plants. However, converting all that power to electricity so it can be effectively used in an ion thruster would be horribly impractical.

        Of course, but since the VASIMR is so much more efficient, you would only need a fraction of that power to have a really, really fast space-only drive.

        If a 190 GW-rated VASIMR engine could be built and the power plant for it ( antimatter? dilithium crystals? ) was available, then I think .999c would seem like first gear. :-P

  • So when can I put in an order for my very own Ironman suit?
  • Does anyone know the risk of explosion of a rocket based on this technology compared to a typical fuel rocket? Does the need for less fuel result in a safer rocket?
    • no way of judging at this point because they only have a partial engine built. it isn't going to be used for escaping the earth's gravity well though. it'll be launched using a standard lift system and then engaged once in space.
    • Re: (Score:3, Interesting)

      by azemute ( 890775 )
      VASIMR is not a conventional rocket and instead uses ionized argon gas as a propellant. Argon gas is inert and thus unreactive; meaning that there's really no serious explosion danger compared to a conventional rocket powered vessel.

      Mind you, much like ion drives, it can only be used in a vacuum, making it totally useless for load-lifting object *into* space and really only useful for moving them around while up there. Ion drives have classically been used as station keeping drives on space stations and
    • Re: (Score:3, Informative)

      They are using Argon which is a noble gas so, other than the pressure they keep it at, there is no chance of an explosion. In fact if there was a fire and the gas was released it would probably put out the fire.
  • Wamprats (Score:4, Funny)

    by Wiarumas ( 919682 ) on Monday October 27, 2008 @02:39PM (#25532019)
    Now if we can only find a pilot that can maneuver down a trench and target a thermal exhaust port 2 meters wide...
  • by Animats ( 122034 ) on Monday October 27, 2008 @02:40PM (#25532039) Homepage

    OK, this is a classic plasma rocket - ionize an inert gas (here argon) and push it out with an electric field (not done in this test). So what are the numbers? How much argon are they using per unit thrust? How much electric power does this take. Is 200KW the input, or the output?

    You still have to carry reaction mass; that's the argon. So you can't just keep boosting as long as you have power.

    It's not a bad idea, but it's not clear how good the implementation is.

  • Old news... (Score:2, Interesting)

    by Meumeu ( 848638 )

    VASIMR is a new high-power plasma-based space propulsion technology

    Yeah, if by new, you mean 30 years old [wikipedia.org]...

  • rob (Score:2, Funny)

    by robcauss ( 1393139 )
    So, I am new here and I have a question, according to the caption under the photo on the site referenced, the unit is UNDERGOING vacuum testing. How long will it be before that guy in the picture implodes? Is this just me?
  • Arrrrrgon? (Score:4, Funny)

    by mfnickster ( 182520 ) on Monday October 27, 2008 @03:21PM (#25532651)

    Q: What's a pirate's favorite rocket propellant?
    A: Arrrrgon!

    Q: What's a pirate's favorite sock pattern?
    A: Arrrrgyle!

    Q: What's a pirate's favorite rating system?
    A: Arrrrbitron!

    Q: What's a pirate's favorite Dudley Moore movie?
    A: Surprisingly, it's 'Micki and Maude'

  • by 32771 ( 906153 ) on Monday October 27, 2008 @04:25PM (#25533637) Journal

    So, does anyone know what the lowest possible orbit is one can use that thing from?

    One reason ion engines cannot be used from ground to orbit is that they need a vacuum to operate, the other one is that the trust is too low to get into orbit.

    With Vasimir however one can get higher trust than with typical ion engines. Could it be possible that suborbital trajectories might be enough?

    To get a usable orbit one needs an engine which raises the perigee from the ground to a point outside the atmosphere (I even tried this in Orbiter once), could it do that too?
     

    • Re: (Score:3, Informative)

      by 32771 ( 906153 )

      While I don't have an answer to my question, let me mention that I somehow had the dream of ion engines being the best thing since sliced bread since they have such a high exhaust velocity (v_e).

      Since v_e affects the delta v linearly as opposed to logarithmically like the mass fraction this is just such a nice knob to play with.

      Unfortunately the power plant weight of the ion engine is something we are stuck with forever, so there is no nice mass ratio involved with ion engines.

      The other thing is that accord

  • by SnarfQuest ( 469614 ) on Monday October 27, 2008 @06:28PM (#25535077)

    This isn't going to become a useful technology, like lasers, until you can mount it on a shark!

Ocean: A body of water occupying about two-thirds of a world made for man -- who has no gills. -- Ambrose Bierce

Working...