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."

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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.

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: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: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: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: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: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

[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.

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:cool but

[caridon20]

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

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.