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Ion Engine Propels Probe to Moon
lenin writes "The BBC is reporting that Europe's first moon mission, SMART-1, appears to be a success thus far. It also talks about the low-cost technology being used and the charged xenon (ion) propulsion system. Can TIE-fighters be far off?"
Ion propulsion technology has been around for quite some time, but has not been used for much else then the deep space probes. Its nice to see it getting some more use. Its also good that other countries are getting more involved with space. Its been far too limited with really only one country going up, since Russia does few launches anymore. I just hope the space program starts to pick up finally after the shuttle tragedy.
What's the hurry? The moon will keep. Think science, not Star Wars.
Can TIE-fighters be far off?
There will be no TIE fighters until we have friction in space. To be able to turn like an airplane in an atmosphere you need something to react against.
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I am a programmer. I am paid to produce syntax not grammar. Deal with it.
We like the moon
Coz it is close to us
We like the moon
But not as much as a spoon
Cos that's more use for eating soup
And a fork isn't very useful for that
Unless it has got many vegetables
And then you might be better off with a chopstick
Unlike the moon
It is up in the sky
It's up there very high
But not as high as maybe
Dirigibles or zeppelins or light bulbs
And maybe clouds
And puffins also I think maybe they go quite high too
Maybe not as high as the moon
Coz the moon is very high
We like the moon
The moon is very useful everyone
Everybody like the moon
Because it light up the sky at night
And it lovely
And it makes the tide go
And we like it
But not as much as cheese
We really like cheese we like zeppelins
We really like them and we like kelp and we like moose
and we like deer and we like marmots
and we like all the fluffy animals
We really like the moon
The concept relies on using power from the solar cells to make the force. This is opposed to carrying fuel.
Using this system only a very small amount of mass is needed to accelerate the craft to quite high velocities, because the energy isn't lifted from the gound but produced in orbit.
On a normal probe the energy for popultion would reside in the fuel carried in tanks, here it resides in the rather large fusion reactor at the center of the solar system.
Sorry for that pun, but..
One point worth making - chemical rockets are getting close to the limits of thier possible efficiency. In contrast Ion engines are in their infancy. The main theoretic limit is that particles cannot be expelled faster than light. You could see very big leaps in engine power in the future..
"You lied to me! There is a Swansea!"
This project cost just 100E6 Euros. That's about one quarter the cost of a single shuttle launch, never mind the astronomical costs of each Apollo mission.
Personally I'd much rather see 4 new projects like this and one fewer shuttle launch.
The maximum thrust of an ion engine (or any rocket engine, for that matter) depends on the amount of matter ejected and the ejection speed (force = counterforce = mass x speed x speed). Since ion engines use extremely small amounts of matter, the push is mainly determined by the ejection speed of the ions. This, in turn, is dependant on the strength of the electrical and magnetic fields used to eject them. The theory of relativity limits this speed as less than lightspeed, BUT also predicts that the mass of ejected particles will be increased as their speed grows, therefore allowing theoretically limitless push, as long as one can produce neccessary voltage.
In other words: the maximum push of ion engine is only limited by the energy source and technical competence in high-voltage engineering, not by any inherent flaw in the technology. An ion engine is perfectly capable of lifting from Earth surface (or chasing X-Wings) assuming you have a suitable power source (nuclear reactor, most likely) and power trasporting/transforming equipment (wires and a voltage converter).
Of course, firing a stream of near-lightspeed ions in atmosphere might cause some radioactivity as they collide with other particles...
But then it is more efficient to use your reactor to throw out particles directly, skipping the step of turbines and electricity generation.
I am not a rocket scientist, but it appears that you've oversimplified the problem.
Can't use the nuclear reaction directly while in the atmosphere, too much fallout. That's why we use chemical rockets in the first place (well, that and the fact that nuclear rockets haven't even been built yet). Suppose we could stick a small nuclear reactor and an engine on a single box and launch it into orbit. That eliminates the space shuttle's current booster system and massive fuel tank.
The ideal earth to moon shuttle should be able to take off from the surface of either body and fly all the way to the surface of the other body, and hopefully have enough reaction mass left to return (not likely, I suppose). This shuttle can't have a bunch of boosters and big fuel tanks that it drops into orbit on its way. When you have to shed 90% of your weight just to make it all the way up, you're operating very inefficiently.
In my opinion, any engine that has the potential to take us from surface to surface earth to moon without all the clumsy boosters is an engine that should be thoroughly pursued.
Then we can build, in orbit around the moon (or somewhere else in the vicinity) the big interplanetary vessels with the nuclear rockets.
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