New Ion Engine Being Tested

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."

Comments

cool but

[ShaneThePain]

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 would be a much greater step towards "casual" space flight. even so, very cool.

Re:cool but

[dbIII]

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.

Re:cool but

[abes]

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

[asadodetira]

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

[Velox_SwiftFox]

Collanders. Giant space Collanders.

Re:cool but

[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 they're turned around and used to decellerate for the second half (note to pedants: apply negative accelleration just sounds dumb, and it is generally understood that decellerate means to accelerate in such a manner as to reduce your velocity with respect to another object, or arbitrary "fixed" point.)

Re:cool but

[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.

For a reaction drive -- such as a rocket engine or an ion engine -- one should talk about thrust rather than about torque.

But yeah, the low-end torque of a reciprocating engine is in a way analogous to takeoff thrust for a rocket engine.

Re:cool but

[Jack Pirate]

I think in this sense, low torque is roughly equivalent with low power. It can get us moving really damn fast, really damn effeciently, but it can't do it very quickly. Therefore, we can't use it to escape earth's gravity.

Re:cool but

[fredouil]

the better and faster way would be to accelerate for the full trip and decelerate by using the gravity of the planet targeted ( and why not use as well friction of the astmospher) like they done with pretty much all mission to mars (for the deceleration only, of course).

Re:cool but

[nocomment]

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).

Re:cool but

[zephc]

The one downside is the giant net you need to catch the 'passangers'

I think you misspelled 'chunks of frozen, red slush'.

Re:cool but

[Anonymous Coward]

Since the engine is linear it doesn't have torque per se.

I think the word you're looking for is 'thrust'.

Re:cool but

[Stripe7]

These would be ideal for use in heavy lift space going airships. http://msnbc.msn.com/id/5025388/

Re:cool but

[caridon20]

Even though the parrent was trying to be funny a space catapult is a sensible idea.
It would drasticly reduce the cost to throw things into space.

One idea is to put a linear acellerator on the side of mount kilimanjaro (strategic position near equator)
and use it to "kickstart" rokets. this way you can get more payload from a smaller rocket that uses less fuel. /C

Re:cool but

[Anonymous Coward]

Yep. Just like they used to launch Fireball XL5 in the 1960s puppet show.

http://www.my-scifi-stuff.com/fireballxl5/images/x l5_on_rail.JPG

I loved that intro sequence when I was a kid.

Re:cool but

[DarkOx]

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.

Re:cool but

[phayes]

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 drives do not look quite so efficient anymore.

Re:cool but

[heavy snowfall]

Wasn't there some movie where they put the rocket miles under water and used the buoyancy to accelerate it? Cool idea.

Re:cool but

[caridon20]

Probably wont give much. The friction against the water will make the craft reach terminal velocity rather fast. /C

Re:cool but

[Deadstick]

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

Re:cool but

[Anonymous Coward]

[...]using the gravity of the planet targeted

The gravity of the target planet will only accelerate you further while you drop deeper down its gravity well.

Re:cool but

[Anonymous Coward]

Kinda like my poop in the toilet ....

Re:cool but

[fjf33]

So how do you stop the gyro without returning that moment to the spacecraft? You still need some kind of mechanism to desaturate the gyros, particularly if the saturation is coming from imbalances on the thrust from your main propulsion, other leaks, or external pressures on your exposed surfaces. The gyros are good for quick repositioning or holding a particular attitude but eventually you need to desaturate them by using some kind of rocket to slow them down.

Re:cool but

[Billygoatz]

If it was a tube that the water was pumped out of, then released it would put even pressure on the craft, but what could the top speed possibly be?

Re:cool but

[Cedric Tsui]

Why would you need nets? We don't use nets to catch the Thor rockets, and they're just a big giant long tube full of solid explosives.

You engineer the catapult to provide the needed amount of thrust, and no more.

Re:cool but

[srussell]

"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 competing, technologies.

--- SER

Re:cool but

[chainsaw1]

The problem here is that

a) Enough water has to come in the tube's end to keep the force increasing
b) The water itself will have friction against the wall of the tube.
c) The air will be denser at the bottom of the tube (though not nearly as much as the water
d) The water surface tension will rob some power at the "release" point without some forethought
e) The tube at the bottom would have to be massive to keep out the force of miles of ocean pushing down, plus miles of the building material also pushing down (this may be counterable with tube floaties).

I also want to say something happens when a stream of water is impacting air at a speed faster than sound. but I'm not sure about that.

I think a tube that collapses from the bottom up as the projectile gains speed could work nicely

Re:cool but

[DerekLyons]

One idea is to put a linear acellerator on the side of mount kilimanjaro (strategic position near equator)
and use it to "kickstart" rokets. this way you can get more payload from a smaller rocket that uses less fuel.

The reality is that you get less payload from much larger rockets. The maximum reasonable 'kick' you can apply is something under 5% of the total delta-V required - but at the cost of adding large amounts of heat shielding and structural reinforcement. (Both of which need fuel to accelerate, thus meaning that when holding the rocket size steady - the total fraction available for payloads goes down.)

On a planet with an atmosphere, catapults don't work. (Nor do jet engine assisted boosters. Nor do Bull type guns.)

Re:cool but

[dbIII]

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

Obviously - it's designed to be used for a completely different purpose. Please look it up at an authorative source.

I suspect it was modded up because I was gently pointing out how way way way off the topic a space elevator is, and that ion drives are a mature technology.

Re:cool but

[Anonymous Coward]

> On a planet with an atmosphere, catapults don't work.

So maybe we should build the catapult above atmosphere (or to the point where it is very thin). For example huge ice hill (about 20km high) in antarktica ?

Comment removed

[account_deleted]

Comment removed based on user account deletion

Don't go getting any ideas

[drrngrvy]

Look, we still can't go faster than light, ok guys?

Re:Don't go getting any ideas

[alxkit]

http://www.news.harvard.edu/gazette/1999/02.18/lig ht.html

oh yeah?

Re:Don't go getting any ideas

[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.

Re:Don't go getting any ideas

[shawb]

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.

Re:Don't go getting any ideas

[XchristX]

[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.

Re:Don't go getting any ideas

[kerrbear]

Look, we still can't go faster than light, ok guys?

If we could just contact Sigma Draconis VI we could skip past warp drive altogether!

Re:Don't go getting any ideas

[Anonymous Coward]

Given how much we (don't) know about physics at near light speed velocities, and how little we know about light period, I wouldn't call our current understanding of faster-than-light travel anything more than "vague conjecture and speculation."

Furthermore, the fact that FTL travel would violate most of our understanding of physics should not be interpreted to mean that FTL travel is impossible, but rather to call attention to the fact that there are still phenomena in physics that are not understood, and until we can explain them, we should approach the current understanding of physics with the same initial skepticism as that with which we approach FTL.

Re:Don't go getting any ideas

[saifatlast]

Aparently we can (in theory) with a large enough magnetic field and by using it to slip in to another dimension.

You're kind of missing the point here. The way such a drive (and similar ones, that for example, compress space in front of the ship and expand it behind) works is that locally, you're not actually going faster than light. You're simply changing the properties of space around you so that you arrive in a shorter amount of time.

It's the same thing with wormholes. If you go through a wormhole, you're not going faster than light, the wormholes just reduces the distance you have to travel.

Check out this article it talks a little bit about some of this stuff (and links to stuff that talks about it more.)

Re:Don't go getting any ideas

[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

"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."

Re:Don't go getting any ideas

[cheekyboy]

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, then after that its all down hill, also mainly because they get married, must
be something to do with all that nagging to do the dishes or the laundry - or it could be all that sex making
the brain go stupid.

Re:Don't go getting any ideas

[Anonymous Coward]

That is just rhetoric, you can't just say there are things we don't understand thus physics should be treated as sceptically as FTL. Those two arn't equal at all, obviouslly we understand current physics far better then any highly speculative FTL ideas.
This doesn't mean FTL is impossible, even if current physics seems to preclude it, because physics does not include all physical phenomenon at this moment. So you can speculate that some more complete physics system might have ways to work around the limit, but that is pretty much it, it is nothing more then speculation right now.

Re:Don't go getting any ideas

[Redwin]

I think we are rather ingnorant/arogant in thinking that we know that we can't go any faster than light.

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.

You know here's me thinking that one of the nice things about science in general is that discussion about other viewpoints is a "Good Thing" and that although things can be certain now they are certain built upon the foundations of our current knowledge. If in the future we discover that something doesn't quite fit in our understanding of the world and its rules then maybe it might be possible to do something that was previously proven to be "impossible".

I'm not sure that arrogant is the best discription of our view of not being able to travel faster than light and I don't think that being ignorant given our current knowledge is a good description either. Maybe foolishness that we stubborn enough to make such a statement whereas "Faster than light travel is not possible given our current understanding of the universe and it's principles" may have been better. As Einstien once said "The important thing is not to stop questioning."

Re:Don't go getting any ideas

[bhiestand]

It's a shame this is posted anonymously. Approached like a true physicist. Nobody ever revolutionized anything by saying "these are the rules and they can't be broken, bent, or changed."

Given the current (and extremely recent) unexplainable phenomena in every branch of physics, from ducting to whether or not gravitons or gravitational waves exist, to the lack of a unified theory, to well, just everything... I'm not saying there are no explanations or theories that cover these, just that the current explanations are incomplete or unproven. It's insane to say that the current world of physics won't be overthrown in the future.

We laugh at the idea of the world being flat because it's so obvious to us now that we know better. We're not laughing AT people for not knowing better, the thought just seems ridiculous to us now. Just like the thought of not being able to break the sound barrier because we didn't know how, or all of the crazy theories about nuclear chain reactions, or all of the wild conjecture about what causes the bends and what is safe for deep sea diving. The simple fact of the matter is that, at the moment, what we have is the best we can think of. The scientific process and open flow of information allows us to constantly improve that, but that also means that (if all goes well) anything that isn't 100% accurate all of the time will eventually be replaced or modified so that it is.

I can only hope that, 100 years from now, my kid will still be alive and healthy, laughing at my generation being unable to cure the common virus, generate electricity without waste, and travel faster than light.

Re:Don't go getting any ideas

[XchristX]

Like I said in my post above. There isn't enough credence for superluminality to even debate its possibility. All of the arguments above are valid only when we question the possibility of FTL. But even the issue of FTL's possibility is without meaning. It's like arguing over the veracity of a random collection of characters and asking whether it forms a word or not. The bottom line is, if I can go faster than light, I can go backwards in time and kill my own grandfather. Now, the indeterministic nature of quantum theory can allow for this (since electrons interact with their own past selves in Hartree-Fock self energy diagrams (for instance), and both the present and "past" wavefunctions are affected by each other. But it's never possible for a quantum particle to completely annihiliate its past self, hence there is no paradox in the quantum realm. However, I am not a quantum particle. I am a classical object subject to classical laws of physics. By classical laws I CAN completely annihiliate my past self if I could travel back in time. Thus I (or anyone else) cannot travel in FTL or communicate in FTL because it produces a meaningless solution.

Re:Don't go getting any ideas

[Anonymous Coward]

well, this barrier tunnel seems to have a constant rate of transmission in lenghts between 4 cm and 11.4 cm beyond that and the signal is undecipherable, less than that and it is no longer a constant. there could be other explainations for the phenomenon other than the microwaves suddenly acheived 4.7c in the 11.4 cm tunnel. however, most of those alternatives still suggest that an effective method of communicating data at FTL speeds will someday be engineerable. any ways, all we know is that the mircowaves take a constant time to traverse the barrier weather it's 4 cm or 11.4 cm.

i've always looked at it a little more simply, what happens when two photons pass through the same piece of space, headed in opposite directions? the two photons relative to eachother one could say from the perspecitive of one photon it is standing still while the other photon just passed through it at 2c. so strictly from that there doesn't seem to be any really hard and fast rule about objects traveling ftl, relative to other objects which are also moving. and every object is moving. light speed as a constant is just a measure of how fast phonons accelerate away when they're produced/released etc

Re:Don't go getting any ideas

[Liam Slider]

Well...it could be that there is some as yet undiscovered mechanism that prevents time travel, preserving causality, and yet still allowing for some form of FTL travel. Or there's the many worlds interpretation of quantum mechanics...which would suggest that if you did go back in time, you'd merely be creating yet one more alternate reality to add to the mix...one in which you kill your grandfather and therefore never were born....but didn't have to be, because you were born in the reality you came from originally where you didn't kill your grandfather.

Of course the real question is....what kind of moron wants to go back in time and kill their grandfather?

Re:Don't go getting any ideas

[blues_shuffle]

Special relativity would indicate that, if one of the photons can be considered stationary, it would observe the speed of the other photon as being c. If the other photon were stationary, it would also observe the speed of the other photon as being c. If there were another observer watching the photons, the observer would measure the speed of both photons as c.
Since the speed of light is constant for all observers, anything travelling at the speed of light will always be observed to be travelling at c, regardless of the frame of reference.

Re:Don't go getting any ideas

[Anonymous Coward]

What is observed and what is happening are two different things. Propagation affects observations and what is observed is not reality.

Re:Don't go getting any ideas

[Yartrebo]

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 containment, etc are all electromagnetic in nature). The electromagnetic force, strong as it is in everyday life, is just to weak to maintain the magnetic flux densities found on a neutral star, no less whatever that magic density is that would cause a dimensional rift (which isn't a proven thing - all that is known is that it'll cause a black hole, whatever that is).

If there is some way to have FLT, then it'll show up first in odd experimental results showing that our theories are less than perfect (they're not, but getting better every year). I would put the shortest odds on gravity behaving oddly at small (sub-millimeter) scales, but so far gravity works as the inverse square for all the experiments executed so far.

Re:Don't go getting any ideas

[debrain]

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?

Re:Don't go getting any ideas

[asavage]

The original poster just described 'FTL' travel wrong. It isn't by physically moving faster then the speed of light but finding another path to the destination that is shorter. While it is very unlikely we don't yet know if it is impossible.

Re:Don't go getting any ideas

[Anonymous Coward]

the fact that FTL travel would violate most of our understanding of physics should not be interpreted to mean that FTL travel is impossible

If anything can propagate faster than c, then special relativity tells us that there is some frame of reference in which it arrives before it leaves, violating causality. For the universe to accomodate this, the universe must be completely deterministic, with a future that is as much set in stone as the past.

Re:Don't go getting any ideas

[Floody]

Special relativity would indicate that, if one of the photons can be considered stationary, it would observe the speed of the other photon as being c. If the other photon were stationary, it would also observe the speed of the other photon as being c.

Indeed. Although its a little difficult to take a temporally based measurement, such as velocity, when your sample rate takes exactly one eternity. Of course, from the observing photon's reference frame this isn't noticable, it's just that any external reference frame will never be able to see the measurement as it will appear to never complete.

This is why the layperson "who says we can't achieve FTL, just because we haven't done it yet, anything is possible!" argument is so silly. If the SR model is correct, its pointless to contemplate FTL as its the same as asking "why can't I get task X completed sooner than right now?". It's a nonsense question with no possible meaningful answer.

However, both SR and GR show us that distance itself is somewhat "flexible." ;) Combine that with the other aspect of ever-elusive gravity, just sitting around being all enigmatic and refusing to give up a universally applicable mechanism means that (probably) the inability to violate causality does not mean that traveling vast "distance" very rapidly isn't possible. But it won't be "Faster Than Light."

Re:Don't go getting any ideas

[Goaway]

According to special and general relativity, the universe is completely deterministic, with a future that is as much set in stone as the past. This may or may not be true - we simply don't know at this point.

Causality violations aren't as simple as that. Causality violations are when superluminary communications cause events to happen in one order to one observer, and in another order to another observer, causing a paradox. Google will give you ample examples of thought experiments to illustrate this.

Re:Don't go getting any ideas

[Goaway]

Your post is quite simply completely false, unless you replace every "we" with "I" and "our" with "my".

Re:Don't go getting any ideas

[Goaway]

No experiments have been performed where actual information has been transmitted faster than the speed of light. Various tunneling experiments are often misunderstood to do this, but they do not.

The article you are quoting is from a science fiction magazine. Hardly a source for reliable scientific information.

Re:Don't go getting any ideas

[xiphoris]

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 :)

Re:Don't go getting any ideas

[Anonymous Coward]

I think XchristX missed the point. Regardless of the justification for accepting limits, the act of accepting them will prevent, or at a minimum, severely hinder direct questioning of that justification, and enbolden the limit. Whereas given time and significant questioning, we might determine that the science behind our beliefs was incomplete...as all science is.

The science of physics is by no means complete. We may very well find in the future that our physics is valid within a certain dimensional frame of reference, and thats why it works so well in the world we live. If you want to stay in this world, or box, then decide now that physics is complete and die happy.

I chose to believe that our science, all of it, is simply a model of a system that is much more complicated. The word "Law" is thrown around far too losely.

I just wish more scientists treated their knowledge as a model, which is always going to be open to revision- even if the foundation of the model is flawed. Too many people, like XchristX, are concrete believers that we've adequately described the laws and thereby faster than light travel isn't possible. Great, they've decided that. It will be unfortunately if it sets back scientists who want to evolve our models to accomodate it.

So my point is that we can stop science at any state in our history and say "This is it, we've described our world- no exceptions are possible". That said, the 60 mph example that was given earlier by someone was a very good (nonarrogant) example of why we can't just accept that science is law. This is the only thing about science that has been unchanging...the fact that we cotinually change our minds about it as it evolves. Models work that way- they adequately describe a system for reasonable predictions- but they aren't laws.

When will people get it through their heads that there are no laws that are not without exceptions and evolution. Call them laws if you must, but not without learning from history, and history tells us that the laws of today are the models of yesterday. Your model says FTL is not possible, and it fits everything we can measure. Funny thing is that the model is defined by what can be measured at the time its created. If it can't be detected, it doesn't exist, right? That's preception. This is where philosophy and science meet.

I feel bad for people who are so locked into the models of the day that they can't see the vast frontier of the unknown. They endlessly defend their models and argue about what is possible and whats not possible in forums such as this. But if they really understood the nature of existence, they'd approach such discussion with far more humility. Many of them simply say "This discussion is pointless, because our 'laws' say its impossible, and they work well for us, so we don't need your heresy". Welcome to the 17th century.

Theoretical Scientists aren't only interested in facts. Thats a mathematician. Only imagination limits us. Scientists who cowardly hold onto the model of the day are employed in the service industry- regurgitating rules set for them and providing services within their narrow paradigm. Happily, there are no Galileos, Newtons, or Einsteins yet to come out of that group of chaps.

Question everything. Ignore those who suggest that doing so is heresy or pointless. Believe in everything you can imagine and look to explain how it might occur. This is how the future will be written, and not in terms of yesterday's scientists.

Re:Don't go getting any ideas

[Goaway]

This will still create paradoxes and violate causality. To see how, consider this:

* Light always travels at c, no matter your own speed. This is a very basic tenet of relativity, and has been tested again and again.
* Place two light detectors at some (large) distance from each other. When either one receives a pulse of light, it will send you a message through a wormhole that this has happened.
* Place a light source between the two detectors.
* Stand some distance away. When the light source sends out a light pulse, the light will travel to both detectors, and each will transmit a message that they received a light pulse at the same time, if they are equally far from the source.
* While you are standing there, your friend is running past you at close to c. To him, light will reach one detector before the other, because the light pulse is travelling at c in his reference frame too, but in his reference frame, one detector will move towards the light source and one away from it. When he receives a signal that the first detector triggered (which will happen before the second one does), he jumps through the wormhole to the second detector and destroys it before the light pulse arrives.

Do you receive one or two messages from the detectors?

Re:Don't go getting any ideas

[Anonymous Coward]

How about actually being honest about the article he quoted rather than just dismissing it out of hand?

The guy quoted from http://www.npl.washington.edu/AV/av_index.html, which claims to be "The Alternate View" columns of John G. Cramer are short (~2,000 word) essays about cutting-edge science. They are aimed at readers (and writers) of "hard" science fiction, as exemplified by the SF stories of Analog, but are about real science, usually physics or astronomy. These columns are published bimonthly in Analog Science Fiction & Fact Magazine.

This is a far cry from a science fiction magazine.

I am not suggesting the magazine knows wtf they are talking about, but at least if you are going to dismiss the quote, you give a valid reason for it.

Re:Don't go getting any ideas

[despisethesun]

Of course the real question is....what kind of moron wants to go back in time and kill their grandfather?

Someone who wants to become their own grandfather, thus leaving them without a delta brainwave. This would then make them immune to any attacks from flying brains who are hell bent on destroying the universe.

Re:Don't go getting any ideas

[Goaway]

None of what you quote invalidates what I said. I never said the article was science fiction, I said the magazine was.

Deep Space 1

[saskboy]

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

[A beautiful mind]

Hah! That's nothing! I've been watching Deep Space 9 ten years ago!

Re:Deep Space 1

[Anonymous Coward]

At least someone realizes this is old news. European Space Agency is always 1 step behind NASA.

Re:Deep Space 1

[Burz]

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.

Re:Deep Space 1

[Anonymous Coward]

Umh, except this isn't old news, this is a new type of ion thruster.

Re:Deep Space 1

[AndroidCat]

The women on The Planet Where They Took Spock's Brain had ion engines since the sixties.

Re:Deep Space 1

[Anonymous Coward]

YET -- it is still an ion thruster. It is in the prototype phase. Deep Space 1 was a real world test, plus 11 other technologies. It is now defunct satellite but it has served it's purpose. And it is still obviously helping scientists in developing better versions of the ion drive.

So, yes this is old news. We already know the ion drive exists. So move on. It is news when it is used to take group of astronauts to Mars.

Re:Deep Space 1

[saskboy]

"So, yes this is old news."

Oh, please! That wasn't my point at all, and it shouldn't be your's either. I posted about Deep Space 1, so people who didn't know the Ion Drive is about 8 years old could look it up and read more about it. Something from a different ship and organization 8 years ago, isn't a Slashdupe. And ESA's drive certainly is Geek News, so don't tell AC-1 to move along.

Re:Deep Space 1

[DerekLyons]

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.

The new engine will do almost nothing to open up space - because the problem isn't the engines.

The problem is power - a power plant light enough to supply the energy a spacecraft of significant size will need simply doesn't exist.

very efficient over long periods?

[Anonymous Coward]

throw that sucker on a generation ship and head out to colonize.

Anyone else?

[wmajik]

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

Re:Anyone else?

[Anonymous Coward]

I thought they made a new game engine and were testing it.

Re:Anyone else?

[Stormwatch]

I'm still hoping they'll release the source so someone can port Daikatana to Mac OS.

Re:Anyone else?

[Anonymous Coward]

My thought was, "I wonder what sorts of improvements they've made over existing ion engines?" I didn't think it was in reference to a game engine, or something to put on some fictional space fighter that nobody on Earth owns...I just thought it would be interesting to see read about real scientists & engineers working to advance space exploration.

Does this mean I have to hand in my geek badge? Or just my Comic Book Store Guy badge?

Re:Anyone else?

[ScottCooperDotNet]

And I thought the TIE Defender was getting an upgrade!

Re:Anyone else?

[AndroidCat]

Wow. You must hate the Mac an awful lot!

Re:Anyone else?

[Anonymous Coward]

The latter. You're a geek, OP is a lamer who thinks he's a geek.

Re:Anyone else?

[ScrewMaster]

Since when did Id Software become defunct?

Re:Anyone else?

[Anonymous Coward]

http://en.wikipedia.org/wiki/Ion_Storm_Inc.

carpool

[User 956]

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?

Re:carpool

[Jeremi]

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!

Re:carpool

[Duhavid]

Yes, as long as your run only on the ion engine.

Re:cool but... oranges and apples

[Anonymous Coward]

The space elevator is not a trans panetary propulsion system. I think they're both good ideas for the intented usage of thier makers.

Increase in the number of grids

[Verloc]

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?

Re:Increase in the number of grids

[asadodetira]

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.

Re:Increase in the number of grids

[Nyeerrmm]

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.

Re:Increase in the number of grids

[Lord Crc]

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.

Re:Increase in the number of grids

[Anonymous Coward]

You missed the point. Next grid would have even higher negative charge than the previous one.

Re:Increase in the number of grids

[Anonymous Coward]

Here's something I've been thinking about. Why not use a coiled path, with the ion source at one end and a grids at the other. The coil itself is charged to repel the ions (the field would be weak towards the center of the coil so ions could get in the tube), and has a small gradient so the ions are forced to slide around the coil to the grids.

You'd need a gyroscope to counter-act the ions moving along the coiled path. But it would seem you could achieve a greater acceleration this way.

~AC~

IANAPP (I am not a plasma physicist), but...

[Tsar]

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?

Re:IANAPP (I am not a plasma physicist), but...

[asadodetira]

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.

Re:IANAPP (I am not a plasma physicist), but...

[maxwell demon]

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 accelerate the yet-unused propellant as well, so if you need less propellant, you also need less momentum to get the desired spacecraft speed. In the extreme case where spacecraft mass is negligible to propellant mass, 1/4 propellant means 1/4 of the mass to accelerate, and therefore 1/4 momentum, i.e. 1/16 energy needed. Which more than offsets the factor 4 above (i.e. in that extreme case, you'd need just 1/4 of the energy). The real spacecrafts are most probably somewhere in between those two extremes (I don't know how much of the spacecraft mass typically goes to propellant initially; of course at the end if the propellant gets used up, the extreme case of factor 4 is reached), but I could well imagine that there's a net win in energy for real spacecrafts.

So, you definitely save propellant mass, but if you save energy or even need more of it depends on how much of the spacecraft mass goes to the propellant.

Re:IANAPP (I am not a plasma physicist), but...

[Anonymous Coward]

Somewhat, I would imagine, but if you actually read the article, you'd have seen that the second set of grids was placed there in order to allow faster ions without dramatically increasing erosion. The erosion is caused by the accelerated ions slamming into the second grid on their way out. This would only happen on the original design when they raised the energy levels to 5kV.

Also, it's not so much an increase in ions as the current number of ions being repelled faster through the system. So there's not 16x as much erosion as you are suggesting.

From the article: "Since they must operate continuously in space for tens of thousands of hours providing a small thrust, ground tests in a vacuum facility must last several thousand hours to prove their reliability"

I don't know whether there is actual erosion on the initial grid, but one would hope that we wouldn't send a ship into deep space with an eroding engine.

Finally...

[RobTheJedi]

One step closer to my TIE Fighter.

Re:Finally...

[Rallion]

I can't believe nobody said that earlier.

Re:Finally...

[Anonymous Coward]

Many people already fight their tie every single morning.. ^_^

YANAP...

[ArcSecond]

Think momentum, not energy.

Re:YANAP...

[arrrrg]

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.

Re:YANAP...

[Anonymous Coward]

That's right, the correct word is "propellant".

is this the same system as...

[j1m 5n0w]

...the one described in this earlier slashdot story? If so, it looks like they've progressed from concept to prototype.

Re:is this the same system as...

[SnowZero]

Not to mention the design mentioned on this page... a long time ago.

Re:is this the same system as...

[masklinn]

Well, Ion thrusters were first worked on during the 60s by the USA and the Soviet Unions, so they're old news anyway, the point here was improving a specific type of ion thruster.

Actually...

[Anonymous Coward]

I thought, when I saw it, that we needed to build a lot of spaceships with two of these, and we would be well on our way to interstellar empire. Just as geeky, I guess, but in a different way.

Ion engine spacecraft!

[nurhussein]

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 before?

Hmmm... I wonder...

[wjsteele]

if this ion engine is any more efficient than the one posted on Slashdot last month. Let me check... nope!

It's simply amazing how many posts get duplicated on this site... it must be part of a plan to drive that advertising revenue stream up a little more.

Bill

Re:Hmmm... I wonder...

[Anonymous Coward]

As far as I can tell, this isn't a dupe. The older article has one double grid, while the new one has four grids (essentially two double grids.) Allows for large power and efficiency gains. So, yeah. It is more efficient.

And it's simply amzaing how many posts get falsely called out as dupes. It must be part of a plan to be really annoying. But then again I suppose that's expected when nobody RTFAs, at least not people who complain about TFA.

Re: ISIWAPP...

[Tsar]

Thanks, ArcSecond, that makes sense. But we still use KE to calculate how quickly the plasma stream will erode the low-voltage grids, right?

gawd the moderation is bad sometimes

[cdn-programmer]

Yup - just stinks. Mod this to funny please.

Re:gawd the moderation is bad sometimes

[hackwrench]

You have a choice. If you mod 'Insightful' we smash your face against the bulkhead. If you mod 'Interesting' we smash the bulkhead against your face.

That's hewey!

[imstanny]

The real question is; do the Europeans have a 'Flux Capacitor'?

Re:That's hewey!

[Teukels]

Pretty Pretty Please, send us some new Flux Capacitors.. The French have broken our last one.

Re:That's hewey!

[ScrewMaster]

Yes, they have a device which can store large quantities of plant seeds ... oh, sorry, that was the Flax capacitor. My mistake.

Re:cool but... oranges and apples

[shawb]

In fact, these would be quite complimentary technologies. Ion drive is pretty much worthless for exiting any kind of gravity well (such as launching from earth) and a space elevator only really gets you as far as orbit. Take the space elevator to orbit, use a little bit of conventional thrust to get out of orbit, then fire up the ion drives and eventually hop to the next planet, where your reverse the process.

Re:New opportunities doesn't mean new realities?

[Firehed]

You think we won't use this to build a fleet of TIE fighters? They could remake Star Wars a third time, but it would be "right here, right now" rather than "A long time ago in a galaxy far, far away."

Read the Article

[Anonymous Coward]

'the good old US of A is putting proven and effective technology into getting back to the moon. '

This is Europe and Australia putting technology into space. US space technology these days is either space based spying on the world or spin from the Whitehouse.

Re:Read the Article

[Anonymous Coward]

This is Europe and Australia putting technology into space. US space technology these days is either space based spying on the world or spin from the Whitehouse.

If you believe that, I have some land I'd like to sell you near Mons Latalis.

Tandem accelerators

[jd]

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 source, so you increase the amount of force needed to achieve the same acceleration.

The ESA are a lot of things - many of them unprintable - but I am prepared to believe they're smart enough to have done studies on multi-stage accelerators as most European physicists have worked on them. (Many particle accelerators in Europe were of this kind, at one point.) If they're only using one grid for acceleration, there's a good chance they'll have crunched the numbers and decided that a single grid was the best bet.

Unfortunately, politics in European space research is (almost) as bad as in NASA, so it cannot be automatically assumed that the solution adopted actually is the option the engineers and ion engine scientists would have preferred. For that reason, I would certainly encourage anyone who knows the science to offer up guesstimates on what different configurations would be like. I would ALSO encourage CmdrTaco and the Slashdot team to see if they can pester someone at the ESA into giving an interview.

Re:Tandem accelerators

[Lord Crc]

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 page mentions 1cm separation between the contacts in a 15kV vacuum circuit breaker).

The references I found mentions a different approach. Negative ions are attracted to a positively charged center. Once they arrive, they're stripped of some electrons, making them positively charged. This causes them to be repelled away from the center. This makes more sense to me as there would be no deceleration phase, from what I can figure.

Then again, I'm no expert ;)

Life Mirroring "Star Trek"?

[Anonymous Coward]

Last week, Slashdot introduced a thread discussing how high-powered magnets might propel spacecraft at warp speed. 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?

Re:Life Mirroring "Star Trek"?

[massivefoot]

In essence, we are talking about an impulse-powered engine.

No. We're talking about an electrically powered engine. "Impulse" is not a form of potential energy, and so cannot "power" anything. Impulse is the integral of force over time.

Re:Life Mirroring "Star Trek"?

[aussie_a]

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

After WWIII of course. I just hope we're the mirror universe.

Re:Life Mirroring "Star Trek"?

[dbIII]

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.

Re:Life Mirroring "Star Trek"?

[Itchy Rich]

Warp engines. Impulse power. Hmmm. So, when do we make "first contact" with the Vulcans?

When you reach puberty.

Re:Life Mirroring "Star Trek"?

[Anonymous Coward]

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

I would say after you get laid.

Re:Life Mirroring "Star Trek"?

[Gromius]

More Star Wars http://www.starwars.com/databank/starship/tiefight er/

Looks like we're halfway there....

Life Mirroring "Star Trek"?

[reporter]

Last week, Slashdot introduced a thread discussing how high-powered magnets might propel spacecraft at warp speed. 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?

of course we know that since....

[efuseekay]

TIE fighters are just short range fighters.

Free Fuel?

[ThndrShk2k]

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."

It seems with there is either a typo, or the mathmatics department of the ESA is outstandingly confident that they will pass all known ways of making nearly perpetual energy, since the engine itself is going to be 10x more feul effecient then the engine used on the mission, which is the first said engine.

That or the Brits are being outstandishly cocky at the US space progam.

Re:Free Fuel?

[Luctius]

You do know that the new engine is NOT the one used in the SMART-1?

Re:Free Fuel?

[ichigo 2.0]

ESA is using an ion drive on the SMART-1 mission. The SMART-1 probe reached it's final destination in lunar orbit about a year ago. The engine in this news is a new improved version of the one used on the SMART-1 mission.

Also, as an European whose tax money is being spent on these ESA projects, I am slightly annoyed by the assumption that "brits" are the only ones behind ESA. The British contribution to ESA's budget is less than 14.2%, which is the portion Italy (the third biggest contributor) stands for, with the Germans (22.7%) and French (29.3%) being second and first.

Re:Free Fuel?

[Anonymous Coward]

Dude you're talking with a us-american. It's a great achievement for a us-american to even acknowledge that there is another country. So let's just accept that we're all brits and we're all horribly jealous of the one and only real nation.

It's not their fault - it's their miserable education and the constant indoctrination.

Re:Free Fuel?

[Anonymous Coward]

Without Britain, America would never have developed the rocket technology to get to the moon, even with what they had after cherry picking the Nazi regimes rocket scientists. Now that continental Europe is providing the resource and motivation to push a space programme, we're getting behind them. Unlike the busted flush, which is the bragging and militaristic USA, the European Union is quietly building a scientific and civil space capacity that will endure. I have no doubt in my mind that the closer partnership between Brtain and continental Europe will provide greater long-term dividends than our previous relationship with the rebellious colonies.

Re:Free Fuel?

[bhima]

No this is not a typo. This is English. SMART-1 has been launched and this new, recently tested, engine proves to be ten times more efficent.

Oh... By the way the "E" in "ESA" stands for EUROPEAN. It may amaze you to hear this... The European Space Agency is comprised of a collection of cooperating nations which includes the United Kingdom.

Given the recent goings on in US Space research funding and some of NASA's recent projects, I'm glad to see the ESA engaging in space research which is not directly related to the military.

Re:Free Fuel?

[Anonymous Coward]

Also, as an European whose tax money is being spent on these ESA projects, I am slightly annoyed by the assumption that "brits" are the only ones behind ESA. The British contribution to ESA's budget is less than 14.2%, which is the portion Italy (the third biggest contributor) stands for, with the Germans (22.7%) and French (29.3%) being second and first.

Yes, but the UK is the only country worth mentioning on a web site based in the US as it is an ally. The rest of the EU is not relevant.

MOD parent down

[Anonymous Coward]

Way off topic, barely makes sense.

Why increase grids?

[Darkman, Walkin Dude]

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 ;)), but we could build all that right now...

Re:Why increase grids?

[Nyeerrmm]

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 definitely a necessity, although there are limits, because each new thruster adds to the mass signficantly.

Re:Why increase grids?

[Darkman, Walkin Dude]

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 build a super sized ion drive, Extremely Large... ELION drives, has a nice ring to it. :D I also like the gyroscope mentioned earlier because firefly has a spinny thing in it too. :D :D

Re:Why increase grids?

[jwdg]

...but the big challenge is getting mass out of the Earth's gravity well at the moment (for which an ion engine is not useful) so adding extra mass is a problem. If extra grids (of very low mass) added to the ion engine can significantly improve its impulse, that can be a very effective way to improve the deep space characteristics while still having something that can be launched in one piece from the Earth.

Re:Why increase grids?

[Darkman, Walkin Dude]

but the big challenge is getting mass out of the Earth's gravity well at the moment

Well I wasn't dealing with the whole "getting it up there" issue... go too far down that road and you're talking about the energy costs to produce the rocket fuel and so on, which isn't the point of space exploration. This would never be a lander, not that that would reduce its usefulness in any way. Besides, the discoveries and resources such a vessel could return would more than make it worth our while, and if we can get the ISS up and more or less running, we can do the same for this. No need to launch in one piece at all. I think another poster dealt with the extra grids question...

Re:Why increase grids?

[Anonymous Coward]

I agree. There's nothing wrong with using one method to get to a space platform, such as a shuttle or even a space elevator, and using a space-only ship for the rest of the trip. Of course, it would have to be large enough to bring a shuttle of some kind, as landing it on mars would be a one-way trip.

As much as I'd love to have a single ship that could lift off from the earth's surface and gad about the solar system, it's technically beyond us yet.

Re:Old News

[angel'o'sphere]

So while the ESA is desperately trying to generate some positive press to help people forget about their recent failings the good old US of A is putting proven and effective technology into getting back to the moon.


Care to point out some of the recent failure sof ESA?

As a sidenote: the currently only ion drive propulsed moon orbiter is a european one ... From ESA not from good old US of A or NASA. And if you don't mind: its good old Europe, not good old USA ...

angel'o'sphere

It doesn't matter

[phiber9]

I'm just happy that new propulsion technologies are being researched. Put an atomic power generator driven by one of this babies and let's take off for Mars.

Re:It doesn't matter

[Anonymous Coward]

Put an atomic power generator driven by one of this babies and let's take off for Mars.
One? If you can put an atomic reactor into orbit, make that lots of drives.

Re:Old News

[Darkman, Walkin Dude]

very little acceleartion thus they'd only be able to get a ship to the moon by creating an increasingly eccentric orbit around the earth then eventually transferring to a very eccentric moon orbit and normalizing. Such a process would take a month at least and more realistically 3-6.

How fast will 50 of them get you there?

Doh!

[Anonymous Coward]

You *completely* missed the point. This is not about going to the moon, but about going to the end of the solar system and beyond. Ion engines could be far more fuel efficient than chemical engines. The SMART-1 was only a proof of concept.

Now the real problem to be solved is from where to get the electrical power. Solar cells are a no go if you go away from the sun and nuclear power is horribly inefficient.

PS: you should have been modded -1, Jingoistic Moron - but this is slashdot after all. Sigh.

Re:cool but... oranges and apples

[Jeremi]

Take the space elevator to orbit, use a little bit of conventional thrust to get out of orbit, then fire up the ion drives and eventually hop to the next planet, where your reverse the process.

Actually, in many cases you can get where you want to go with little or no thrust at all, simply by riding the elevator up past the altitude of geosynchronous orbit. The higher above that altitude you go, the greater the centrifugal force from being spun around the Earth, so it's just a matter of calculating when to let go of the elevator.

Dumb health question

[Jeremi]

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?

Re:Dumb health question

[Anonymous Coward]

I'm no rocket scientist, but since ions are some form of charged particles, just like alpha- and beta- radioactive particles; I presume you won't live happily ever after.

Re:Dumb health question

[Ezza]

IANARS, (... Rocket Scientist)

  Firstly, a traditional rocket would work in an atmosphere. I doubt these work in an atmosphere, in fact I'm guessing that being in a vacuum is pretty much a prerequesite for their operation (a bit like the inside of your CRT tv set). But lets humour ourselves and assume they'd operate in an atmosphere and you're standing behind one.
  The pressure of these ion engines is so small that I suspect the air between you and it would probably nullify, or at least very much disperse the charged particles shooting out the back.
  If we humoured ourselves a little more in the other direction, and assumed that you were behind this engine in the vacuum of space (maybe you are Zentradi or something), then we can assume the ion stream hits your skin directly, and you are alive to feel the sensation.
  Then I guess you've got a bunch of charged particles shooting at you very quickly onto a very small area of your skin. Besides almost certainly giving you cancer, you'd probably wind up with a bit of minor tissue damage as the particles slowly drilled into your skin.
  I suspect that would pretty much be it. You'd feel a tingle and/or stinging sensation, you might get an "injury" a bit like an insect sting and eventually the cancer might kill you.
  But I wouldn't worry about it too much :)

Re:Dumb health question

[LuckyStarr]

I guess he would be electrocuted if the engine is connected to the ground. Ions are charged particles and enough of them will make a huge potential differential.

Got an idea

[dascandy]

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 travel through time.

Didn't think about what paradoxes you'd need, and you'd probably bump into yourself at the moment of turnaround, but aside from that...

No research done whether this could be true, but it's an idea I've been playing with.

Re:Got an idea

[TuringTest]

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.)

Re:Got an idea

[Anonymous Coward]

Newton agreed with you.

Einstein, in 1905, proposed the change between time and space to be a curvature which caused something called a time/space warp, thereby negating your assertion.

You have been wrong for more than a century.

Mars vs Outer Planets

[sanman2]

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 performance we can squeeze out of this technology. Let's see how high they can make the thrust go. I read on the newsgroups that ion engines could one day emulate the VASIMR concept which can achieve a wide variety of thrust characteristics.

Or what about a 2-stage rocket design? Just have a regular chemical rocket first-stage with high thrust to escape the earth's gravity, and then from there use ion engines to power the 2nd-stage.

Re:Mars vs Outer Planets

[Anonymous Coward]

If you had read all the article you would know the answer to your first question.

Re:Mars vs Outer Planets

[DerekLyons]

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?

Nope; because of the elephant in the room that the various ion engine research folks won't talk about and hope you won't notice - Power. There doesn't exist a power plant light enough per megawatt to propel something as small (relatively speaking) as an Apollo CSM - let alone the larger spacecraft that a manned mission to Mars will require.

Re:Mars vs Outer Planets

[sanman2]

I've heard this point before, but consider a 2-stage system where the chemical first-stage gives the main escape velocity, and the ion-thrusting second stage functions like the SMART-1 probe. Perhaps we'll have to see if any exotic energy technology pans out, like fusion, quantum nucleonics, or some such. I wouldn't hold my breath over it, but you never know. Even SMART-1 was solar-powered despite its terribly low power density, and yet solar continues to improve in efficiency.

Re:Old News

[anno1602]

These ideas have been floating around NASA and the defense industry for years.

Ion engines, yes. Dual-Stage ones? I was under the impression that they were new.

So why haven't these engines been put into use?

What are you talking about? Dual-Stage ion engines are just being developed, and conventional ion engines are/were in use both on NASA and ESA probes.

As a result the only projects suggested were either unmanned deep space probes

You seem to be implying that unmanned space exploration is useless. It is anything but. If at all, the presence of humans in space is of questionable scientific value.

they provide very little acceleartion

If you had RTFA, you'ld have seen that this new technology remedies exactly that problem and woud lend itself for Mars missions.

Not so dumb.

[imsabbel]

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

Re:Not so dumb.

[c4ffeine]

Somewhat offtopic, but what the hell.

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

Does anyone have any links to reliable data about what happens to unprotected humans in a vaccuum? I'm curious and having a hard time finding anything reasonable accurate

Re:Not so dumb.

[TuringTest]

I'm curious and having a hard time finding anything reasonable accurate

That is probably due to not being any real experimentation in the subject, only speculation.

Re:Not so dumb.

[pavon]

Actually, a human has been exposted to vacuum, at least partially, during a test (on accident). The link goes to Nasa's ask an astrophysicist answer to your question. It is an interesting read, even if it does dispell my childhood view of boiling blood and exploding eyeballs, ala Total Recall :)

Re:Old News

[masklinn]

So why haven't these engines been put into use?

They have, check Deep Space 1. NASA's Dawn Mission will also use ion thrusters, and over 100 soviet satellites have used ion thrusters in the past 30 years.

I have you now!

[Highroller]

...and to my TIE Interceptor!

Re:I have you now!

[Meneth]

Bomber, Advanced, Defender, Phantom... the list goes on. :)

Re:I have you now!

[Liam Slider]

The Bomber and the standard TIE are both flying death traps. The others though...sweet rides.

Re:New opportunities doesn't mean new realities?

[Itchy Rich]

Is anyone even trying anymore? Just because the engine exists doesn't mean anyone will put it to use?

Ion engines are already in use. If these guys have come up with a performance increase then that new development will certainly see use... unless it's prohibitively expensive (unlikely), someone comes up with something better almost immediately (unlikely), or the world ends very soon (also unlikely).

Re: ISIWAPP...

[Anonymous Coward]

Did you properly read the article? The new higher KE is possible because they managed to reduce the erosional effects.

Specific impulse fetish

[XNormal]

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 probably be welcome, too.

Prius / Carpool

[ink]

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.

Torque can be a big problem

[YA_Python_dev]

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 have a similar problem on the ISS (but there the torque is generated by friction with the upper atmosphere and small gas leaks), where the american gyroscopes must be periodically unloaded firing the russian thrusters, using precious propellant (this, of course, isn't due to a fault in the gyroscopes).

One of the good things of ion engines is that they can very finely tuned to not have pratically any off-center thrust: the Smart-1 spacecraft has almost never had the need to use it's gyroscopes to absorb thrust generated by the ion engine.

And, of course, the torque generated by really big motors (e.g.: Space Shuttle or Ariane 5 main engines) must be corrected by the same engines with a closed-loop control, because there is no way a gyroscope can absorb that much torque.

Re:Torque can be a big problem

[luna69]

> It's just an object. Doesn't mean what you think.

Nice sig.

Re:Torque can be a big problem

[YA_Python_dev]

Thanks :-)

old tech is new again

[Anonymous Coward]

Very cool stuff, but reading I couldn't help but thinking that this is strikingly similar to pentode/tetrode tubes in ooold electronics. OK, you're dealing with charged particles and not electrons (so I guess more a thyratron than a hard valve), but still, much the same principles are involved, even up to the multiple grids to counteract each problem that comes along. Kinda cool to see this stuff being dredged up again.

Re:Old News

[Anonymous Coward]

You seem to be implying that unmanned space exploration is useless. It is anything but. If at all, the presence of humans in space is of questionable scientific value.

they provide very little acceleartion

Agreed.

Ion engine

[seven of five]

.... now there's an idea with potential...

Not more fuel efficient

[Anonymous Coward]

LESS fuel efficient, the fuel is the energy source (solar or nuclear in ion engines case). It's a shitload more mass efficient though...

210,000 m/s?!?

[deander2]

is that a typo in the article? are they really accelerating their propellant to 70% the speed of light?!?

Re:210,000 m/s?!?

[deander2]

oh wait, never mind. i'm an idiot. :-P
SOL ~= 300,000 km/s, not m/s.
210,000 m/s / 300,000,000 m/s = 0.07% the speed of light
(much more believable)

Charge accumulation?

[JourneyExpertApe]

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.

Re:Charge accumulation?

[Ruie]

Does anyone know how these engines avoid accumulating a net charge over time?

They have an electron gun that shoots electrons the same way the ions go, so the net charge is close to 0.

Just curious

[tcatt]

Along with all these new advances in engines and thrust, are there research divisions in exisitance that are trying to invent better spacetravel braking systems?

Imagine a day when we actually discover another inhabited planet and incorporate every means of advanced sophisticated propulsion we know to get there, only to approach their planet full-thrust.. backwards! and then deploy parachutes to land...

Practical? Sure. Graceful? No. Awe-inspiring first impression? Nah-uh.

Re:Just curious

[tcatt]

Wait a second!!

Maybe if we put scary faces all over the parachutes... !!

I hereby retract my previous post.

Re:Just curious

[joskay]

The bouncing ball landing would be funny. Aliens are waiting in excitement over the new contact but have to wait till the space craft bounces around for a bit.

Re:cool but... oranges and apples

[fjf33]

But think about the environmental impact of doing something like that. You are wasting a non-renewable resource that rightly belongs to everyone on Earth. I don't think anyone should be able to do something like that until we are really clear on the impact on Earths like from the rotation slowdown that would happen from this. Even more I think we should impose a ban on any and all fly-by assisted missions.

What about shielding?

[MillenneumMan]

The velocities theorized by this technology are mind boggling, but wouldn't a collision with a tiny piece of space dust be, for all intents and purposes, completely catastrophic for the vehicle at that speed? A collision with a grain of sand when travelling at 70% of the speed of light would involve a VERY large quantity of kinetic energy. Without some kind of shielding beyond our current technology levels, wouldn't the vehicle would be severely damaged?

Re:What about shielding?

[Anonymous Coward]

Dude, you're an idiot. Do you really think that we're capable of traveling at 70% the speed of light? Try 0.07%

oh, shut up, both of you!

[ChrisCampbell47]

Huygens was a great success. Beagle 2 was a great failure. Ion thruster improvement = success. Ariane 5 = failure (initially). Et cetera. Cue rhetoric.

http://www.google.com/search?q=esa+failure

Re:oh, shut up, both of you!

[angel'o'sphere]

Lol,

the poor guy I answered to got modded into oblivion.

Technicaly Beagle was no ESA mission but a private funded one. Beagle "only" used an ESA vehicle to reach Mars. Thats a little bit nitpicking of course ;D

Well, my parent had the opinion that ESA had more failed mission in the recent history than NASA, and I don't think that this is true.

angel'o'sphere

Re:cool but... oranges and apples

[Wolfier]

> I think we should impose a ban on any and all fly-by assisted missions.

I think you're trying to be funny here...

Re:cool but... oranges and apples

[xiphoris]

It still takes the same amount of thrust (or, I should say, just force) to ride the elevator up to geosynchronous orbit as with any other system. The advantage of the elevator is that you don't need to also lift your fuel with you; it's transmitted as electricity through the elevator (or as a laser beam or some other system).

But, a space elevator is definitely not a "free ride" into space. There will always be gravity to overcome, and that takes energy.

Alleged FTL experiments

[hweimer]

"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 physics undergrad should know that both the group and phase velocity of electromagnetic waves can have arbitrary values and that this doesn't contradict special relativity. The important question is how fast information is being transmitted and for this neither the group nor the phase velocity is suitable.

Re:cool but... oranges and apples

[shawb]

But a fair amount of energy could in theory be recovered on re-entry. Picture a pulley system where a roughly equal mass travels down one side of the elevator while pulling the "launch" cargo up the other side. It realistically wouldn't be a rope, but probably magnetic braking similar to regenerative braking in an automobile or some similar technology, and energy gained from this would supplement the energy needed to lift the cargo going up. This wouldn't exactly be a free ride either due to friction and other inefficiencies, as well as the simple problems with trying to schedule equal loads up and down; but such a system could mitigate part of the energy costs of launch.

Re:cool but... oranges and apples

[StarKruzr]

No, he raises an important point.

How do you return the rotational energy to the earth? Losing it would be a REALLY BAD THING for the planet. Has anyone done the math on this?

Re:cool but... oranges and apples

[corngrower]

The earth already is loosing rotaional energy. Quite a bit in fact. It happens naturally. The moon has pretty much lost all its rotational energy.

Re:Old News

[Anonymous Coward]

50 will get you there a little faster, but the extra weight and power requirements put so much overhead on the launch that the cost is not worth it - you can launch the equivalent of a convertible car into orbit for maybe less than 10 million USD these days, but a hummer would cost you maybe 200 million USD.

The efficiency of this engine beats the numbers at small payloads - hence the wide adoption in smaller spacecraft and long-lasting missions. But when you want to get somewhere fast, it is really not an option. This is one reason why geostationary communication satellites are still being carried from low orbit to 36k-km level with old-style rocket fuel carriers, and not ion engines. It would just not be worth the wait, and you can't have your xxx million costing comsat sitting on the slow train for 3 months when it's life expectancy is only 3 years.

Re:cool but... oranges and apples

[fjf33]

Yes I was, glad you got it.

Re:cool but... oranges and apples

[Anonymous Coward]

Has anyone done the math on this?

Yes.
The amount of rotation lost would be so miniscule that it would be almost immeasurable.
The Earth would lose less (much less!) than one second per century from the lost angular momentum due to a Space Elevator.
As the other respondent pointed out, the Moon is sapping much more rotational energy from the Earth than will anything Man does in the forseeable future.
Also, note that the elevator can also gain angular momentum for the Earth by "catching" ships.

Re:cool but... oranges and apples

[Hamzter]

The earth has so much rotational energy that we'll make almost no dent in it by launching craft into space with a space elevator. The Earth has about 2 × 10^29 J, I'm now sure what kind of speeds you'd get off the cable, but if you travelled to the very end (probably ~twice geosync unless there's a counterweight), you'd be at an altitude of 70,000km, and a speed of about 5000m/s. That means you'd have 12.5MJ/kg of mass that you sent up. In order to use just 1% of the earth rotational energy you'd have to launch 1.6 x 10^20 kg into space. That's a huge ammount, unless someone feels the need to put australia on Mars I don't think we'll have a problem...

Re:cool but... oranges and apples

[Xaoswolf]

What about the giant rotating pinwheel/space elevator thing that the Freds used in the Doom novels?

Wait...

Does this get automatically modded down as it proves that I read past the first novel?