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New Nuclear-powered Spaceship Design Revealed

Posted by CowboyNeal on Thu Sep 20, 2007 09:49 PM
from the goes-to-eleven dept.
Iddo Genuth writes "A U.S. based company introduced an innovative propulsion system that could significantly shorten round trips from Earth to Mars (from two years to only six months) and enable future spaceships to reach Jupiter after one year of space traveling. The system, which may dramatically affect interplanetary space travel is called the Miniature Magnetic Orion (Mini-Mag Orion for short), and is an optimization of the 1958 Orion interplanetary propulsion concept."

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  • Didn't we (Score:5, Funny)

    by scoot80 (1017822) on Thursday September 20, @09:52PM (#20691819) Journal
    recently have an article about trip to mars in a week? So.. this is really.. an inferior mode of transport for all those Mars holidayers...
  • hopefully (Score:3, Funny)

    by weirdcrashingnoises (1151951) on Thursday September 20, @09:53PM (#20691829)
    Hopefully this spaceship will be able to slow down before it reaches mars.

    Unlike some spaceships... http://science.slashdot.org/article.pl?sid=07/09/13/2328233 [slashdot.org]
    • Re: (Score:3, Insightful)

      What makes you think the photonic drive wouldn't be able to slow down? Does the drive not work if you flip the ship in the opposite direction?
      • Re:hopefully (Score:5, Funny)

        by Propaganda13 (312548) on Friday September 21, @02:29AM (#20693437)

        1) Start your trip from Earth Orbit, by firing up them engines and transferring into a nice trajectory to our friendly-neighborhood planet Mars.
        2) ???
        3) Profit!... no, I mean, half-way through the journey (or actually, just a little bit before half way, to give some leeway for properly transferring into a Mars orbital path), switch off them engines!
        4) Swing your craft around so that the pointy-end is towards the trajectory's rear and the business end (the engines) are pointing towards the trajectory's forward path.
        5) Fire up them engines again! Hey presto! You're now flying into nuclear explosions!
        6) ???


        fixed
        [ Parent ]
        • Re:hopefully (Score:5, Funny)

          by Minwee (522556) <dcr@neverwhen.net> on Friday September 21, @10:27AM (#20696851) Homepage

          6) Go back to school. Go directly to school. Do not pass Go, do not collect $200.
          7) Learn about strange new concepts like Galilean Relativity, Newton's Laws of Motion and Inertial Frames of Reference.
          7a) And no, I'm not going to link you to Wikipedia's articles on those. You're going to have to go with step six for that.
          8) Now that you understand why step five is no different from step one, you can figure out what step six was supposed to be.
          9) For extra credit, write "I will not talk out of my ass about Physics" 6x10^24 times on the chalkboard.

          [ Parent ]
  • by Kaenneth (82978) on Thursday September 20, @09:57PM (#20691867) Homepage Journal
    An WHUMP Orion WHUMP based WHUMP drive WHUMP can WHUMP be a WHUMP bit WHUMP rough, WHUMP any WHUMP study WHUMP on the WHUMP effects WHUMP on cargo/passWHUMPengers?
  • by patio11 (857072) on Thursday September 20, @10:02PM (#20691913)
    ... this just means you get to nowhere faster.

    (Sorry, reflexive poke at Wyoming. Wyoming has wonderful people, natural resources, and breathable atmosphere. Mars is 0 for 3. Jupiter doesn't even have a surface to land on, but now we can hurry up to get there and not land on it! Like the robot we're sending had some place it would rather be for the marginal time...)
  • Pics (Score:5, Funny)

    by StikyPad (445176) on Thursday September 20, @10:05PM (#20691935) Homepage
    Here's a few pics of the Mini-Mag [maglite.com] in action. Looks vaguely familiar... Interesting how the cargo capsule seems to release from one end and dock at the other. Very intriguing.
  • Bulk??? (Score:3, Interesting)

    by Goonie (8651) * <`robert.merkel' `at' `benambra.org'> on Thursday September 20, @10:09PM (#20691973) Homepage
    If their gadget for doing the z-pinch thingy is anything like the Z machine [wikipedia.org] at Sandia you won't be putting it on a spacecraft any time soon...
  • by Anonymous Coward on Thursday September 20, @10:11PM (#20691987)
    If you unscrew the cap in the stern of the spacecraft, you will find a spare nuclear reactor behind the battery terminal.
  • Reduces travel time how? (Score:5, Interesting)

    by Cousarr (1117563) on Thursday September 20, @10:13PM (#20691997)
    First off, I am not a rocket scientist, but I am studying for a BS in Aerospace Engineering.

    How exactly is this supposed to reduce travel time? Current lengths of travel are not due to a lack of available thrust or due to amount of fuel available but rather the path taken to reach the destination. Currently in order to travel to say Mars Hohman transfers [wikipedia.org] are often used. These paths and others like them take a certain amount of time to complete, and stronger engines or more available Delta-V allow only for more instantaneous entrances of the transfers or more allowed change in course once at the ship's destination.

    In order to reduce time traveled a different orbital mechanic is needed. Even if a ship were to travel in a straight line toward a destination at a rapid enough speed that it would not have to meet up with it too much further along in its orbit it would have to be able to kill relative speed quickly enough to enter a capture orbit.

    Anyone know what orbital transfer method they're saying that this engine makes possible?
    • Re:Reduces travel time how? (Score:5, Interesting)

      by StefanJ (88986) on Thursday September 20, @10:32PM (#20692161) Homepage Journal
      As I recall, Hohman orbits are nice ellipses with body A at perisol and body B and aposol. You make a burn to get into it and out of it; the delta-v required is the difference in velocity between a body in a "circular" orbit at that radius and the velocity of a body in the elliptical orbit. If the planet happens to be at that point, you then just need to make another burn to get into orbit. Timing is important.

      Even Hohman orbits are too "spendy" for chemically fueled rockets. Thus the complex back-and-forth gravity-assist paths that NASA probes take on the way to the outer planets, and the use of aerobreaking by Mars probes.

      Other, faster transfers are possible. You just enter another sort of elliptical orbit whose path intersects earth's orbit when you leave it, and the destination planet's orbit at a time when the planet will be there. Of course, you have to have a spaceship capable of the much greater change in velocity to enter these orbits.

      The linked-too documents suggest that the "mini mag" is not only fuel efficient (read: high Isp), but has a decent amount of thrust. This means it CAN make the drastic changes in velocity necessary.
      [ Parent ]
    • Transfer orbit (Score:5, Funny)

      I believe they are using the "Journalist Transfer Orbit." This is a highly specialized piece of orbital mechanics: basically, you take the average distance to the destination as given by Wikipedia and divide by the spacecraft's top speed.

      [ Parent ]
      • Re:Reduces travel time how? (Score:4, Interesting)

        by Nefarious Wheel (628136) * on Thursday September 20, @10:47PM (#20692285) Journal
        My guess is that it turns around about half way during the trip to start slowing down.

        Wouldn't necessarily be half way, we're not talking linear vectors are we? If we're playing catch-up with a planetary target the crossover point might be a bit later than km/2. It's more expensive to escape the closer you are to the sun's gravity well, but I'd think a lot of the energy would be soaked relative to the velocity of the target, i.e. there may not be as much energy to dump near the target. Space ain't flat, found that out from my office mate who was doing the orbital geometry for Pioneer Venus 12/13 some years back (which had the inverse effect, being inward from EO).

        I don't know why he kept a separate set of comps in furlongs per fortnight, but us programmerz was wierd back then.

        [ Parent ]
      • Re: (Score:3, Informative)

        Hohman transfers are slow and cheap; that's why we use them. If you have a much more energy-dense fuel supply (plutonium certainly fills the bill) there are much faster routes available.

        I prefer a holtzman Transfer. Get there in 0.01s. Only bad thing is no
  • Slashdotted? (Score:3, Funny)

    by barakn (641218) on Thursday September 20, @10:25PM (#20692101)
    These people are visionaries, except when it comes to anticipating large server loads.
  • Jup in a Year (Score:4, Informative)

    by Tablizer (95088) on Thursday September 20, @10:26PM (#20692113) Homepage Journal
    and enable future spaceships to reach Jupiter after one year of space traveling.

    The New Horizons probe, heading to Pluto, took slightly more than a year to reach Jupiter. However, there was no need to stop (park in orbit) and it didn't need to carry bulky life-support stuff. Thus, it could take the fast train.
           
  • Blog troll. Link to real info here. (Score:5, Informative)

    by Animats (122034) on Thursday September 20, @10:41PM (#20692237) Homepage

    First, this is a blog troll, to drive traffic to some ".info" site. The actual paper, "Proposed Follow-on Mini-Mag Orion Pulsed Propulsion Concept" [aiaa.org] presented at an AIAA conference last year, is more useful.

    The basic idea is to create a small fission (not fusion) explosion using magnetic compression. Nuclear weapons use chemical explosives to create an implosion, and during the implosion the fissionable material is compressed hard enough to get a 1.5x to (maybe) 2x density increase. With magnetic compression, a small pellet can be compressed hard enough to get a 10x density increase. This allows smaller explosions, around 50 gigajoules instead of the 20 terajoules of a fission bomb. They want to use curium or californium as the fuel, rather than plutonium.

    They also want to use magnetic containment, rather than an Orion-style "pusher plate" sprayed with oil. Unclear if that can be made to work.

    The experimental work (they compressed an aluminum cylinder with a big magnet at Sandia) was done back in 2002. This isn't really under active development.

    It's not a totally unreasonable idea, but it would be a huge job to make it work. For one thing, the plan is to assemble a large spacecraft in orbit, not to take off from Earth. It doesn't help with the problem of putting mass in orbit.

    • by Ungrounded Lightning (62228) on Thursday September 20, @11:04PM (#20692393) Journal
      They also want to use magnetic containment, rather than an Orion-style "pusher plate" sprayed with oil. Unclear if that can be made to work.

      Ought to be a cake-walk once they've got the field in place to make it go "bang".

      The pellet is ALREADY confined in a mag field. The re-expanding plasma from the explosion dumps much of its energy into compressing the field between the plasma and the conductor that created it, making the field stronger (and dumping a bunch of the energy back into the conductor as electricity for potential reuse or consumption).

      Should be easy to create a selective leak in the desired direction and more fields to guide the plasma as it makes its getaway. (In fact the compressed field toward the vehicle can be used as a spring to return some of that collected energy to the plasma, further increasing the exhaust velocity. And/or the energy from the compressed field could be used to create or strengthen the "nozzle" guiding fields, just-in-time to guide the burst of plasma.)

      Lots of opportunity for cute electric/magnetic/plasma engineering tricks here.

      And unlike fusion the time scale, from ignition to completion of the exhaust cycle, is short, so plasma instabilities aren't an issue.
      [ Parent ]
  • The common thread that we keep coming back to is that to really do spaceflight, you must have some form of nuclear power. The laws of physics are profoundly strong on this point. Space is too far and gravity is too strong for chemical rockets to really be successful.

    The ideal solution is to find a source of uranium in space, beyond Earth's gravity well, such that, we can mine the uranium in space, and fuel nuclear powered spacecraft from perhaps the moon. I don't see that happening any time soon, as, it is my understanding that its is practically a fluke that a relatively small body like Earth should wind up with such a heavy ore at all. The gods were kind to us during our solar system formation, and it feels unlikely that any asteroid should have a significant uranium deposit.

    That leaves us to launching live reactors into space from Earth. Unfortunately, despite safety precautions, the environmental movement makes the development of nuclear powered spacecraft a political impossibility. We can't even build a reactor on land without a mountain of red tape and lawsuits from the greens, even when we know that building such reactors are necessary to combat global warming. Putting a nuclear reactor into something that flies is unthinkable to them, and they would surely think that putting a nuclear reactor into a rocket is downright crazy. Even RTGs, relatively benign, are met with protest. Were it up them, there would be no pictures of Saturn at all from Cassini.

    In this one area, the left wing claim to scientific curiosity falls flat on its face. The science is not worth the risk. I think the key to be able to do this, really, is going to be to engage the right wing instead and paint such research as a matter of national security. The right wing, despite its proclaimed conservatism, has a penchant for throwing caution into the wind when it suits it. Heck, they'd blow off global warming just to be able to keep driving trucks. Put a nuclear reactor on a spacecraft to get to Mars in a few weeks, sure, why not? For them, though, the issue is going to be why. Doing it just for the science isn't going to cut it. However, the right does have a penchant for engaging in enormous projects for ideological goals - witness the cold war with Russia, the current war on terror and the invasion of Iraq. None of THOSE projects were cheap or short term, and honestly, only the right wing has the zeal needed to overcome failure after failure as would occur in a really long term space colonization project. Even if you disagree with it, religion is an enormously powerful motivator.

    Thus, you'll never get many righties to buy into space for the science, or the future profits, because both don't really do much. But if you could sell them space as a religious duty, then by God, they will say screw the left, throw a hundred billion dollars a year into building nuclear rockets that this country needs, all to create christian colonies on planets and take resources from asteroids. If anything, one could always further argue that with the Russians claiming the North Pole, then, the USA has to claim (something), and it may as well be Mars and the asteroid belt. Asking them to void the UN Treaty on claiming stuff on space would elicit an automatic yes - as the right is already predisposed against the UN.

    Surely such a project would be better for the world than the war on terror.

    The point is this, and this goes for both left and right. We are entering a time of great consequence for the United States, if not the world, and, it is time for us to stop seeing each other as enemies simply because we have different ideologies. We can make our differences work for us, so long as we express what we want for ourselves as individuals, not as collective party members, and from there identify those strengths we have in each other.

    In my case, I selfishly want to see the USA building a fleet of nuclear, manned, rockets, mining asteroids, and colonizing other planets. And, if I have to read the
    • Re:That's nothing.. (Score:4, Insightful)

      by cduffy (652) <charles+slashdot AT dyfis DOT net> on Thursday September 20, @09:56PM (#20691861)
      That's unfair. Gibson's "design" was loose speculation, whereas hard math has been done both on the original Orion and on this potential improvement.

      Certainly, neither of them has existed in practice -- but one was wild speculation, whereas the other had (and has) actual engineering.
      [ Parent ]
      • Re:That's nothing.. (Score:5, Informative)

        by Rei (128717) on Thursday September 20, @11:12PM (#20692447) Homepage
        Still, this has very little to do with Orion apart from them both being nuclear pulse propulsion. They only call it a successor to Orion because most people are familiar with Orion.

        Orion has already been obsoleted by a similar (but much more effective) design using normal-sized nuclear explosions -- Medusa [wikipedia.org]. Medusa reverses the Orion design, having a parachute in front towing the craft, and detonating the explosives in front of the parachute. It uses structures in tension instead of compression (lighter), it allows the explosions to be further from the craft (less radiation), allows a longer acceleration stroke (smoother acceleration), and captures a larger percentage of the explosive energy.
        [ Parent ]
    • Re:That's nothing.. (Score:5, Informative)

      Reading the (now Slashdotted) article, it sounds like this design came directly out of research done into antimatter catalyzed micro-fission [wikipedia.org]. ACMF is a well-proven technology that uses minuscule amounts of antimatter to kickstart or enhance a fission reaction. Because the technology was fairly straightforward and had good returns for antimatter quantities that are reasonable to produce, NASA was funding research into an engine called ICAN [astronautix.com].

      I remember that there was some talk of actually launching a small probe based on the concept, but apparently the plan was scrapped. (Probably to help fund manned space travel.) Whatever antimatter confinement technologies they were working on may have led to the development of this new magnetic confinement fission technology. Or it could just be a coincidence.

      Either way, nuclear technology of this sort is fairly well developed and is not a pipe dream. At least not from an engineering standpoint. Getting the risk adverse US Government and NASA to actually build one of the many known-quantity engines we have on hand is a completely different ball of wax. They're still trying to get us reliable LEO access (Thank God for Griffin is all I can say), so I doubt we'll be seeing any advanced engines in practice until the CEV/Orion project enters its third phase.
      [ Parent ]
      • Re:That's nothing.. (Score:4, Insightful)

        by donaldm (919619) on Friday September 21, @02:36AM (#20693481)
        Even if this craft can reach speeds of 10% the speed of light we would still be limited to interplanetary exploration and exploitation (human nature dictates this). As far as interstellar travel goes it would still take about 45 years to send a spacecraft to the nearest star, not to mention the 4.5 year transmission delay. Still interplanetary travel is a big breakthrough if this article can be believed.

        The real breakthrough would be an interstellar spacecraft (the realm of Science Fiction at the moment) and this would really open up our galaxy, however a person would have to live for thousands of years to visit each solar system in our galaxy for just one day even assuming travel between each solar system is almost instantaneous. Think "Star gate technology. Well I did say in the realm of Science Fiction :-)
        [ Parent ]
        • by Ihlosi (895663) on Friday September 21, @02:54AM (#20693581)
          Even if this craft can reach speeds of 10% the speed of light we would still be limited to interplanetary exploration and exploitation (human nature dictates this).



          The solar system is a big enough place for exploitation, and when we're done with the planets and their moons we can look at the Kuiper belt. That should keep us busy for the next couple of centuries, at least, and also allow us to use technologies to actually analyze nearby star systems without having to send probes there just yet.


          And once the solar system gets too small for use, we probably have the necessary technologies, experience and infrastructure to send something on an interstellar voyage (probably a generation ship or even a small planetoid outfitted with propulsion systems).

          [ Parent ]
          • Your Vision for Lewis and Clark? (Score:4, Insightful)

            by WED Fan (911325) <akahige.trashmail@net> on Friday September 21, @08:53AM (#20695609) Homepage Journal

            The solar system is a big enough place for exploitation, and when we're done with the planets and their moons we can look at the Kuiper belt. That should keep us busy for the next couple of centuries...

            And the President said, "Lewis, Clark, I want you to walk around the block of the White House, its plenty big, and there's probably a lot for you to see. When you're done with that, check out Virginia. Once that is done, I want a complete survey of everything east of the Mississippi. That should keep us busy for a century."

            Lewis replied, "What about the vast unexplored reaches of the west?"

            To which the President slammed his fist into the desk, "Slow down, Sparky, that would take lots of money that would be better spent on the vast wasteland of New Jersey. And, it would take a long time and nothing good would come of it, I'm sure. And, it would take you forever to get the results back to us. And, you'd smell when you got back. Hell, Clark smells already. Now, you guys do as I told you, none of that 'Vast Vision' stuff."

            Knowing they were beat, Lewis and Clark resigned themselves to taking a walk around the block.

            "Besides," the President said, "When you finish up, you can both do commercials for Lost Horizon Airlines."

            Hey, why does exploration have to be serial?

            [ Parent ]
    • Oh dear... (Score:5, Funny)

      by Roger W Moore (538166) on Thursday September 20, @09:57PM (#20691877)
      ...I think someone forgot to tell the sun.
      [ Parent ]
    • Re:Nice idea but... (Score:4, Insightful)

      by hedwards (940851) on Thursday September 20, @10:02PM (#20691915)
      A treaty is only as good as the signatories. There is no particular reason why the signatories couldn't write and sign a new treaty that just specified that there were to be no nuclear powered satellites in orbit or nuclear weapons in space.

      As that is more or less the intent. A spaceship that was nuclear powered would really only be an issue if it was allowed to orbit the earth long enough to fall out of orbit.
      [ Parent ]
    • Wrong (Score:3, Informative)

      Nuclear weapons, yes.

      Power sources, no.

      There are plenty of probes and spy satellites that are powered by plutonium-laden RTGs.
      • Re: (Score:3, Insightful)

        Orion operates by exploding a weapon against a thrust plate, so it really qualifies as a weapon, which is at least one reason Orion was cancelled. I'm not sure how the treaty applies to space-based reactors, but theres definitely a large difference betwee
        • Re:Wrong (Score:4, Interesting)

          by zippthorne (748122) on Friday September 21, @12:04AM (#20692741) Journal
          Which is quite ironic, considering Orion was conceived as a way to reduce nuclear weapons stockpiles...
          [ Parent ]
          • Re:Wrong (Score:4, Insightful)

            by TheRaven64 (641858) on Friday September 21, @06:34AM (#20694433) Homepage Journal

            A hammer can be either a weapon or a tool.
            And, while I'd object to a ban on hammers in general, I wouldn't object to a ban on people swinging hammers within a foot of my face. Scale this up by a few orders of magnitude, and you've got nuclear arms limitation treaties.
            [ Parent ]
    • Cassini (Score:5, Informative)

      by mark0 (750639) on Thursday September 20, @10:28PM (#20692119)
      You mean like a plutonium powered vehicle [wikipedia.org]?
      [ Parent ]
      • Re:Cassini (Score:4, Informative)

        by MillionthMonkey (240664) on Thursday September 20, @11:05PM (#20692409) Journal
        An RTG doesn't count. If they use plutonium, it's Pu-238 (alpha emitter) with a half life of less than 90 years, not Pu-239 which has a 90,000 year half life (fewer watts per gram) and can support a chain reaction (so it's needed for other things). There are lots of them scattered about the former Soviet Union so if you're doing any hiking there, avoid heat-emanating ceramic objects. [iaea.org]

        When not using solar panels (conspicuous and vulnerable) Americans like to power their satellites with RTGs. The Soviets put 35 reactor-powered satellites in orbit and only a few RTG-powered satellites. What was forbidden by the treaty was nuclear weapons, specifically including tests. An interstellar spacecraft powered by nuclear explosions would be a great way to sneakily test your weapons in full view of everyone.
        [ Parent ]
    • Re:Nice idea but... (Score:4, Informative)

      by GreggBz (777373) on Thursday September 20, @10:42PM (#20692249) Homepage
      The use of nuclear weapons is banned, yes.

      There has been research into nuclear rockets (NERVA) [wikipedia.org], and nuclear power sources.

      Project Prometheus [wikipedia.org] shows promise. Already, most of the long range probes that NASA has use radioactive decay as a power source, which is pretty safe and reliable.

      [ Parent ]
    • Not like old Orion (Score:3, Interesting)

      This one is going to be built in orbit. It will never take off or land.

      OTOH, the "fuel" pellets are going to be made of fissionable materials. I hope they point the nozzle in a direction that doesn't result in un-detonated bomblets burning up in the atmosp
        • Re:Not like old Orion (Score:5, Informative)

          by Ungrounded Lightning (62228) on Thursday September 20, @10:53PM (#20692333) Journal
          You do realize that burning coal has put more Uranium into the air than all the atomic explosions combined right?

          I'm more worried about Strontium 90 and radioactive iodine.

          Given that Hanford deliberately released a BUNCH of radioactive iodine upwind of an indian reservation at least partly to see what its effects would be on the "marginal population" of indians and rednecks downwind (leading to a considerable increase in birth defect constelations and graves' disease), I suspect others are with me on that.
          [ Parent ]
    • Re:What about manned? (Score:5, Insightful)

      by flyingfsck (986395) on Thursday September 20, @10:18PM (#20692033)
      How do deal with all those explosions in your car engine?
      [ Parent ]
      • Re: (Score:3, Informative)

        A four, six, and eight cylinder engine will have their pistons out of phase from each other as to provide a continuous and smooth power curve. Now compare that with a single piston engine (lawn mower, weed eater...etc) and take notice of the excessive vibr
        • Re: (Score:3, Insightful)

          What's the difference? An internal combustion engine is coupled directly from the explosion all the way to the road, well at least in a manual car. The reason you don't feel each explosion though is that instead of using one big one there are thousands of
          • Re:What about manned? (Score:4, Informative)

            by Duhavid (677874) on Thursday September 20, @10:45PM (#20692271)
            There is also the flywheel, which dampens the effect of each combustion event.

            Also, it is not an explosion, but rapid combustion.

            Further, the magnitude of the events is quite different
            ( in a car engine, the events are relatively small,
                on orion, well, bigger ).
            [ Parent ]
              • Re:What about manned? (Score:4, Informative)

                by gravij (685575) on Friday September 21, @02:50AM (#20693553)

                "Dampen" doesn't mean what you think it means. Or rather, it wouldn't if people would stop adding superfluous letters to seem more intelligent.

                The word is damp. The infinitive is "to damp" and a device which damps is a damper. There's no need for the extra -en unless you want to have a confusing half-synonym for moisten.
                 
                Care to back that up? No source that I could find online supported your claim. All I found was this:
                (from dict.die.net)
                Source: Webster's Revised Unabridged Dictionary (1913)

                Damp \Damp\, v. i. [imp. & p. p. Damped; p. pr. & vb. n.
                      Damping.] [OE. dampen to choke, suffocate. See Damp, n.]

                      2. To put out, as fire; to depress or deject; to deaden; to
                            cloud; to check or restrain, as action or vigor; to make
                            dull; to weaken; to discourage.

                Source: Webster's Revised Unabridged Dictionary (1913)

                Dampen \Damp"en\, v. t. [imp. & p. p. Dampened; p. pr. & vb.
                      n. Dampening.]

                      2. To depress; to check; to make dull; to lessen.

                Dampen \Damp"en\, v. i.
                      To become damp; to deaden.
                [ Parent ]
          • Re:What about manned? (Score:5, Interesting)

            by modecx (130548) on Thursday September 20, @11:31PM (#20692549)
            Isn't it kinda sad that people on a site which is supposedly for nerds can't naturally grasp the idea of waves, pulse-width, modulation, duty cycle, and psychophysical thresholds?

            Exactly what kind of nerds are they cranking out these days?
            [ Parent ]
    • Re:What about manned? (Score:4, Informative)

      by Fox_1 (128616) on Thursday September 20, @10:25PM (#20692089)
      1. lot of explosions in a car engine, and we're all mostly still sane. Seriously though they are small contained explosions (couple grams of material) that vent plasma, there is no reason why people in the passenger compartment would even be aware of each individual explosion. The point is that these are nuclear weapon sized explosions, but many smaller ones providing relatively constant thrust. It won't be jerky.

      2. I don't know if you understand how acceleration works. But Fewer larger explosions would make for a rougher ride. And you don't get up to speed on a day to day basis, that would be a weird way to fly a space craft.

      3. 1 g constant acceleration for a few hours is pretty freaking fast. This engine could do the thrust of the space shuttle - which is more then 1 g, but why would you do 12 g for more then a few minutes?
      If you do 1g acceleration for a full day you are going about After 1 day, you are going 800,000 m/s - 800km/sec or 288,000 km/hour mars is about 78million km away - so you can see how this is going, if you stop accelerating at this speed it's about a 4 or 5 million km a day just coasting, or 20 or so days to get there. So it's silly to do more then 1g acceleration, unless you are leaving a planets surface and need to reach escape velocity. So no worries about weird physical effects from the acceleration - now long term zero g is a whole'nother type of problem, but again no need to make it a long trip with this kind of power.

      [ Parent ]
    • Re:What about manned? (Score:5, Funny)

      by Tablizer (95088) on Thursday September 20, @10:37PM (#20692213) Homepage Journal
      1. How will people deal with the psychological effect of the never-ending pounding brought by this type of propulsion?

      Explains...why...Kirk...talked...like...this. The...future...is...here.
             
      [ Parent ]
    • Re:What about manned? (Score:5, Informative)

      by Grond (15515) on Thursday September 20, @10:59PM (#20692361)
      The full press release notes that the maximum acceleration would be a mere .6 G's or so, which is more than Mars but obviously less than Earth. This is unlikely to result in any unknown physiological changes. In fact, the at least occasional exposure to g-forces would probably be beneficial compared to continuous micro-gravity.

      Anyway, a 100 metric ton craft would be pretty wimpy. That's 5% of the Space Shuttle's mass, for instance. I suspect this would be an unmanned mission. (For reference, the Apollo Service Module & Lunar Module together were about 40 metric tons and the longest Apollo missions only lasted 12 days).

      Also, the 'ignition mass' for the fastest version would be a whopping 1300 metric tons of plutonium. Using uranium prices as a stand-in, that's about $300 million in fuel. That's an awful big price tag for just getting a larger probe to Mars faster.

      [ Parent ]
    • Re:What about manned? (Score:4, Funny)

      by fyoder (857358) on Thursday September 20, @11:03PM (#20692381) Homepage Journal
      I think many of your concerns would be addressed by the addition of an inertial compensator [wikipedia.org]. As the wikipedia article points out, this may not fully protect against sudden shocks. It also seems less effective on people suffering from HPD (hamminess personality disorder), who may be thrown about much more violently than people less drama prone.
      [ Parent ]
    • Re:jupiter? (Score:5, Funny)

      by moosesocks (264553) on Thursday September 20, @10:37PM (#20692215) Homepage
      Obligatory:

      Fry: Hey, as long as you don't make me smell Uranus. (laughs)
      Leela: I don't get it.
      Professor: I'm sorry, Fry, but astronomers renamed Uranus in 2620 to end that stupid joke once and for all.
      Fry: Oh. What's it called now?
      Professor: Urectum.
      [ Parent ]