Slashdot Mirror
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?"
Rockets use the same priciple that ion propulsion uses, the law of action and reaction (one of Newton's Laws, can't remember which one off the top of my head). Basically matter is accellerated out the back of the engine (by chemical means in the chemical rocket engine, and by using electro-magnetic forces in the ion propulsion engine). This accelleration causes causes a force to be placed on the engine that is equal to, but oppisite in direction, to the force accellerating the matter.
To answer your first question, Deep Space 1 used ion propulsion.
...interesting if true.
I think what confuses some people is that we're used to pushing against something to go somewhere. People have a misguided idea that it's the exhaust pushing against the ground that makes a rocket go, but it's actually the rocket pushing against its exhaust that makes it go. Basically, you mix two things together in a chamber, and under high pessure you shoot ("throw" in the parent's words) the resulting gases out the back end, and away you go. There's no need to interact with the atmosphere which is why rockets work in space and propellers don't.
This is really a test bed for the ion-drive technology - although even on this mission, its effective to do it this way, once in lunar orbit the drive can make slow adjustments to cover the whole surface, without having to carry huge amounts of propellant. Over LONG periods of operation, the ion drive is something like 10 times more effective in terms of fuel carried vs thrust given compared to chemical rockets - and that figure is set to improve as research progresses. SMART-1 is an important step in that research. The Ariane-5 launch rocket is a fraction of the size/cost of the Apollo/Saturn-5's..
In the future missions you will see these sorts of drives giving much faster flight times to Mercury, Mars, Jupiter, Saturn.. - although for the outer system you may need nuclear instead of solar power.
Yes both this and parent are dupes from previous thread..
"You lied to me! There is a Swansea!"
I spent a lot of time studying this technology while I was working towards my Bachelor's Degree. Okay, let's get some facts straight, for those of you without a degree in Mathematics or Physics:
6 ap r99_2.htm
t ar /
1) Ion Propulsion is NOT new technology. The Russians and German's have been experimenting with Ion Propulsion since the early 1950's. NASA is actually a late comer to the game, although the first with a completed ion propulsion engine.
2) Ion Propulsion do not work in an environment with an atmosphere. An ion engine does not have enough force to lift a sheet of paper more than a few inches.
3) An Ion Engine is very simple in design. For a simple explanation, an inert gas is ionized and injected into a chamber with an opening on one end. The opening has a magnetized torid ring around it. Using the right hand rule (make a fist, stick your thumb out like you are hitchhiking...your thumb is the direction of the electric current, your fingers are curled in the direction of magnetic field flow) you create an electrical flow around the metal torid ring. The resulting magnetic field 'pulls' the ions through the ring, resulting in propulsion.
4) The reason for slow inital acceleration is because the force of the ions passing through the ring is very small, but the velocity of the ions is very high. So, since there is no friction or other losses in space, after a period of time the velocity of the ions leaving the ring increases the velocity of the engine. After a matter of days the engine can be travelling at 10-30,000MPH.
For more information and history on Ion Propulsion engines you can go to the following websites:
http://science.nasa.gov/newhome/headlines/prop0
http://www.grc.nasa.gov/WWW/PAO/ds1.htm
http://space-power.grc.nasa.gov/ppo/projects/ns
Rockets use the same priciple that ion propulsion uses, the law of action and reaction (one of Newton's Laws, can't remember which one off the top of my head). Basically matter is accellerated out the back of the engine (by chemical means in the chemical rocket engine, and by using electro-magnetic forces in the ion propulsion engine). This accelleration causes causes a force to be placed on the engine that is equal to, but oppisite in direction, to the force accellerating the matter.
All means of propulsion -on Earth and in Space- use Newton's third law.
In practical terms, the difference is that Ion engines use energy from the sun, to accellerate small portions of matter (ions) over a long period of time.
Rockets use chemical energy to throw out matter, typically violently for a short period of time.
For these reasons Ion engines are predicted a bright future for travel over long distances (to the moon is unusually short in this context), there efficient use of energy wins out in the long run.
However, it seems unlikely that they could be used for lifting things into orbit; then you need to quickly accelerate to high speeds and get out of the athmosphere. Ion Engines are probably not suitable for chasing X-Wings around the Death Star either for that matter.
Tor
ok Alpha Centauri is a star system consists of Alpha Centauri A, Alpha Centauri B and Proxima Centauri, that appears as a single star to the naked eye. Of that system we are closest to Proxima Centauri not Alpha Centauri. The distance to Proxima Centauri is 4.36 light years.
In Kilometers this is:
41,220,846,106,794
So you calculation is a bit off in the time scale.
To reach it in 10 years you would have to be going roughly half the speed of light or 150,000,000 meters per second
I was thinking of the immortal words of Socrates, who said: "I drank what?" - Chris Knight (Val Kilmer)- Real Genius