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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?"
Here's the original.
Yes, I do know why ion engines are a good idea. Just leave Star Wars out of this.
Panurge has posted for the last time. Thanks for the positive moderations.
Before we can build X-Wings, we have to figure out what the hell "Fusial Thrust" means.
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.
It also talks about the low-cost technology being used and the charged xenon (ion) propulsion system. Can TIE-fighters be far off?
Yup, that's how technology goes, straight from moon probe to TIE fighters. No intermediate steps necessary. No life support, no radiation shielding, necessary. I can't wait to buy my A-Wing.
For ever action their is an equal and opposite reaction.
Rockets move exactly in the same way an Ion propulsion engine would move. By forcing mass out the rear. Unlike jet or propeller, a rocket ejects its fuel as a means to propel itself.
(sigh) Then the Emperor has already won.
You are not the customer.
Sure the Ion drive is a really neat addition, but it's soooo slooooow. It's going to take them 15 MONTHS to get there! And the payload isn't really greater at all. It takes longer to get any large loads going. The US space program got people to the moon and back in what...2 weeks? It may be slightly more economical, but it just doesn't seem practical.
Hopefully they can perfect the ion drive, however through this to increase the speed and payload capacity. Then we might have something really cool... (until the anti-matter reactor comes online...)
As interesting as ion engines sound, it seems like they might be rather limited in use. After all, with such low acceleration, procedures such as leaving the orbit of a planet or moon might be impossible, or at least take decades. Anyone with more specific knowledge than the Beeb wanna weigh in?
The opinions stated herein do not necessarily represent those of anybody at all. Deal with it.
Sorry to disappoint you, but yes.
Damn space cadet!
If we combine this with the space elevator, we can send shit to the moon on 6 AA batteries!!!
10 ?"Hello World" life was simple then
For every action there is and equal and oposit reaction.
Repeal the 17th Amendment TODAY! Also Please Read http://www.gnu.org/philosophy/right-to-read.html
Ion propulsion systems wouldn't be any good for fighter craft. They use very low accelerations, integrated over large periods of time. This makes them a good candidate for interplanetary flight, where you have weeks and months to build up large velocities with the small acceleration, but really crappy for combat where you want to be able to accelerate quickly. Well, maybe you don't, but I do.
Of course you don't understand - after all, this time it really IS rocket science.
anyone else wondering where such a small system is getting the energy needed to ionize a large amount of xenon atoms?
Great Atrocit
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.
It's pretty simple, really. In the atmosphere, rockets work by pushing against the air, as you might expect. However, when the rocket leaves the atmosphere and enters a vacuum, or what we physicists call an "inertial frame," then your thrust is pushing against this inertial frame, which is kind of like what physicists used to call the "Aether." Aether has gotten a bad name, since Einstein proved that electromagnetic waves don't need to travel in the aether, but this has led to the misconception that aether doesn't even exist. Mach's principle shows that Aether is real, since it is what we need to push against to rotate and accelerate in space.
Banach-Tarski Overdrive
TO THE MOON!!!
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.
- - - - - - - - - - -
I am a programmer. I am paid to produce syntax not grammar. Deal with it.
If you are wondering how rocket propulsion can work if Newton's laws dictate that every force generates an equal and opposite force, you're not distinguishing between force and acceleration. If you mass roughly 50 kg, and I hit you with a 500 kg Acme weight with a force of 1 000 N, you'll accelerate at 20 m/s^2, but the Acme weight will only accelerate at 2 m/s^2. Equal force != equal acceleration.
Although, Ion's second time around are just as fun!
Yo Grark
Canadian Bred with American Buttering...American Buttering....American Buttering...
Canadian Bred with American Buttering
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.
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
Check out this page for some nifty things you can build that may work on ion-propulsion. I thought it was a hoax at first, but my friend convinced me to build it in high-school, and the thing really did work. Of course, the efficiency was terrible. We were using an old monitor as a 20,000 volt power source, so power dissipation was probably pretty high. That was enough to lift the 2 gram device and 1 gram of payload.
A deep unwavering belief is a sure sign you're missing something...
ok, this is finally retarded enough. Rockets do not push against the air, they do not push against the "aether." Hell, they don't even push against the launching pad when they are on the ground.
Rocket exhaust (the flames, etc.) provide a force, yes, but THEY PUSH AGAINST THE ROCKET.
If you are standing on ice (wearing skates) and you throw a bowling ball away from you, you will slide in the opposite direction. The bowling ball doesn't need to hit anything for you to move.
Are we going to get daily news on this project?
--
"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
...probe Uranus?
Look at the dude's posting history. Read his comment and laugh. It's funny.
Oh, please. Everybody knows that rockets have to have air to push against, but aether? Please. Quit trying to fool the above poster with your farcical stories about aether.
Any respectable scientist knows that space travel is impossible anyway, that NASA never put any men on the moon, and that any satellite in orbit that you might THINK you see is really swamp gas, reflected off of Venus...
And as for my sibling posters in this subthread, you might wanna turn up the sensayumor knob in yer forebrain.
Ce n'est pas un vrai mouvement de robot!
A chance to use this link
For ever action their is an equal and opposite reaction
I'm sorry, but that dosen't explain the curry from my local Chinese restaurant. The reaction is way bigger than the action. Perhaps they should have powered SMART-1 using that.
This is just a cool way of saying they're driving the probe to the moon in the new saturn car. :)
*There's Klingons on the starboard bow, scrape em off Jim!*
Dans cette place interdite. not interdit.
...we can expose the American moon landing SCAM! ;-)
so we get the lasers that make noise and move like they're nerf gun darts too?
At least the war on the environment is going well
This one is more reputable, I believe credited to Arthur C. Clarke.
...
It was a short story about an Earth-to-Moon (orbit-to-orbit) space race, in the spirit of the Kremer prize. The spacecraft were propelled by ion engines, which were energized by Whimshurst-type machines, which were powered by
bicycles.
The racers pedaled their way to the moon, the pedals effectively powering the ion engines that drove them. The race took several days, with the right stuff added in for absurd athletics, rest breaks, minimal life-support, race security, etc.
No doubt someone here will do the math that I never bothered trying to do. One of these days, maybe I will.
The living have better things to do than to continue hating the dead.
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!"
Hey guys, this stuff isn't just dumbass. A considerable amount of thought and understanding had to go into making it look that retarded.
In short, it's a troll. A real troll at that, not the pseudo trolls we usually see around here.
Not exactly the best troll I've ever seen, but in a way it's nice to see a Slashdoter make the effort to at least try to uphold the old traditions.
KFG
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
...guide to the galaxy. Obviously this maneuver is very unnatural for all space vehicles, but it looks so cool rich people will surely want to have stuff that does that implemented in their spaceships. Just for showoff, no matter how inefficient and ridiculous that would seem :)
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
Anyone care for a Reactionless Thruster ?
----- In Your Cubicle No One Can Hear You Scream...
To perhaps give you an intuitive idea of what all this action/reaction stuff
.
. ht m
people are talking about is imagine firing a gun.
It "kicks".
The expanding gasses push the bullet out one end, sure, but they also push the
whole gun back against your shoulder. If your shoulder weren't there . .
Another example would be trying to hold onto a fire hose. If you've never had the opportunity just rent Roxanne. Then you can go down to your local Kaybee (or other) toy store and buy a cheap little plastic thing that puts this to actual
use in a rocket. Or go here if you're a do it yourself kind of guy:
http://bradcalv.customer.netspace.net.au/wrbook
KFG
The article gives examples of other ion powered craft.
We all know what hides in the dark spots that they wish to explore and that no picture of what is lurking in the darkness ever will make it back to earth.
..I have not watched too many movies...
So all we can do is wait for the message that they have lost contact with the spacecraft..
Tuesday is when the ion drive gets switched on for the first time.
Reality is defined by the maddest person in the room
"Dark Sith" should that be moderated redundent? Or are there happy-go-lucky-smiley-face-Siths I'm unaware of?
heh.
The Kruger Dunning explains most post on
yeah, if it travelled in a straight line.. its gonna be in orbits that keep expanding/contracting, etc. etc. etc. That saidm average velocity may be 22MPH towards the moon, but thats completely different than speed
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WHO ATE MY BREAKFAST PANTS?
I hate those self-important A-holes who have those xenon propulsion systems. It seems like every night that I go for a short trip in low earth orbit, at least one schmuck has to fly by with those damned things turned on. How am I supposed to see where I'm going when I'm being blinded by the obnoxious blue glare that they spew? If they're the only ones who can see anything, it's not making things any safer overall.
I swear, I'm going to start flashing these jokers with my laser range finder if they don't get more considerate and stop using those damned xenon units in congested orbits.
if your '71 chevy truck is slow, you just put in a bigger engine right?! so how about a bigger ION drive. and a small nucleur reactor.
i suppose you do lose some efficiency by carrying your own fuel, but nuclear power is far more efficient than solar power right now.
with larger ION drives, or more small ION drives, and enough power from the reactor, this may be able to compete with a rocket engine for inter-solarsystem travel.
but then again, id rather have laser,mazer, or phaser cannons. I'll travel really really slowly if I have a really big gun!
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another advantage would be less vibration during accelleration. Imageing sending a team to Alpha Centauri using standard rockets. They would have to burn for 3 solid months to accellerate and the same to decellerate. 3 months is a long time to be strapped to a chair.
this solves the lack of gravity problem as well. Just accellerate at a rate the would be near 1G or at some acceptable level of force, then spin the ship around and do the same thing for decelleration. This way you would have artificial gravity for a good portion of the trip. I can't imagine the side effects of a couple of years is zero G, and what happens when the team trys to go to the plannet with no muscles built up for planetside life.
Alpha Centauri is something like 5,644,944,000 kilometers away, this is most likely a 5-10 year trip. Yes, artificial gravity would be good.
Also, the waste material from the reactor could be used as the actualy propellant(maybee, IANORS(I am Not a Rocket Scientist) and then you wouldn't have to store it, you could just eject it out the back of the craft.
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
This isn't the first time an ion engine has been used in space. NASA's Deep Space 1 probe toured the solar system for over 3 years with an ion engine. This probe isn't very well known, since it was just a test bed. But in the end it made some history by performing the closest encounter ever with a comet.
--
Luck is just skill you didn't know you had.
Lets see your Buick make it to the moon on a tank of gas ;)
You obviously have never heard of The Happy Sith.
"Molest me not with this pocket calculator stuff."
- Deep Thought
...and actually that they'll never appear.
Fast space travelling is cool, but any kind of fighters are meant to be killing machines - I hope we'll never need to see anything like Star Wars in real life.
Besides, TIE fighter would only be the first step. claimed to be only for "defending the Homeworld". Sooner or later someone would build a Star Destroyer, too. And eventually something like Death Star.
Thinking this and the bloody history of humanity, it's best to hope that no other intelligent lifeforms will ever be found from space. Humans are known to be too hasty in loading their weapons.
Of course none of this is any kind of concern unless we're capable for inter-star travelling. That may take some time, yet...
“Wait for Hurd if you want something real” –Linus
>Ion Engines are probably not suitable for chasing X-Wings around the Death Star either for that matter. Easy. Install a flywheel to capture wasted energy when braking your TIE fighter.
It's not offtopic, dumbass. It's orthogonal.
Now all we need is to invent a way to project sound waves in space, then we can hold re-enactions of all the battles in Star Wars :)
Can TIE-fighters be far off?
Those things were terrible! they took a shot and a half to kill, no shields, no warheads. Wake me up when they launch TIE AdvancedX1 or TIE Defenders. Those are cool.
SAILING MISHAP
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...
Deep space one and many communications satellites already use them.
They dont really make sense as backup as you have to have two completely separate systems to support them (propellant feed, power, etc). Thats a lot of mass for something that may be nothing more than backup.
They make perfect sense for unmanned missions. Theres typically no hurry to get where youre going, and the mass benefits are large.
They can be used on manned missions, the crew would simply rendezvous with the craft in high Earth orbit rather than being aboard for the entire escape spiral from Earth.
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
on the TIE fighters were solar panels - that's why the TIEs were "short range fighters".
Clear, Dark Skies
what's next? warp drive and the Vulcans visiting?
Jerry Fletcher,
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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).
This is very true, but
1 All ion engines currently discussed use solar cells as their energy source. The whole point is that you only bring matter, not the energy source to accelerate it.
2 If you are prepared to bring an energy source as well, then you are basically back to the rocket case. Sure, you can bring a nuclear reactor, use heated atoms to drive a turbine and generate electricity, and then use the electricity to accellerate ions. But then it is more efficient to use your reactor to throw out particles directly, skipping the step of turbines and electricity generation. Btw researchers are working on such nuclear rocket systems. These would be much more efficient than anything we have today, but also politically problematic to say the least.
Tor
I understand that ion engines have pretty slow acceleration, so how long is it going to take this thing to reach its destination? The moon is not really that far away in the whole scheme of things, would it not be quicker to use a conventional engine ?
Electronic Music Made Using Linux http://soundcloud.com/polyp
It should be noted that the world has sent only a tiny set of probes to the Moon in the last 30 years - and only one of them (Lunar Prospector) was a NASA mission. The other US mission (Clementine) was also a very small and inexpensive mission, so basically since Apollo ended our spending on actual lunar missions has been maybe 2% what we've spent on Mars. Does that make sense to anybody here?
NASA still seems very reluctant to send anything, but they are being forced to by a recent review of solar system priorities - also several private firms and a bunch of other countries seem to be getting in on the Moon mission act - see the mission list from the Moon Society.
Energy: time to change the picture.
Remember it was a LONG time ago, in a galaxy FAR FAR AWAY.
moo.
"Frankly, the physics of using rockets in space has never made sense to me"
You wouldn't happen to work for the New York Times, would you?
Is that a job offer? Because I could really use the money.
(note that the above contains intentional grammatical no-nos, designed to indicate my overwhelming potential as a New York Times editor.)
It may help to think of any rocket-type (and ion, too) propulsion based system like this:
Basically, the center of mass of a fueled up rocket does not change. If you had a rocket at a dead stop and started a burn, you'd throw as much stuff behind you as your displacement was forward. Hence in a simplified 1D rocket model (which is actually pretty close to correct, diffusion is actually pretty minimal) your center of mass never moves.
Arguably, you could say this means that the entire rocket array (fuel and all) never actually moves: just spreads itself out, with the useful "stuff" at one end of the displacement.
Yes there are. They smile when they torture you.
Does the phrase "clone army" ring a bell?
Also, the books talk about Storm Troopers being grown instead of recruited.
Clear, Dark Skies
You guys seem to be forgetting Deep Space 1. Deep Space 1 was launched by NASA on October 24, 1998 and uses ion engines. I'm not sure if they are the same type, but are xenon ion engines none the less.
On a side note Deep Space 1 had a cooler mission in actually navigating really close to an commet and taking pictures and running test.
Actually, I was thinking more along these lines.
My favorite proposal from the near past was the magnetic bubble. Create a large static magnetic field - a simple dipole will do- in space, and then fill it up with plasma. The plasma causes it to expand greatly in size, which is important because the dipole field decays as r^-3. It would act much like the Earth's own magnetosphere with a shock upwind and a long tail. But unlike at Earth, this magnetic bubble can be oriented in any direction. It has been compared to a balloon in operation.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
They were brought along, or more accurately, they are created from a supply of xenon that is brought along. The energy used to ionize the xenon and accelerate the ions comes from the solar panels.
"I'm not impatient. I just hate waiting." - My Dad
From the article:
"Ion drives do not produce the sudden burst of forward momentum you get from a chemical rocket. But over the long-term they are considerably more efficient and many future probes will use them. "
"Dark Sith" should that be moderated redundent? Or are there happy-go-lucky-smiley-face-Siths I'm unaware of?
Yes. Be afraid.
I mean, since the thrust is so weak, there must be a benefit somewhere, right? None of the articles touch on this that I've read.
Blar.
I forgot the most important side effect. The magnetic bubble is very good at deflecting even high-energy ions and electrons, i.e. just about everything besides neutrons, neutrinos, and electromagnetic waves like UV, x-rays, or gamma rays. This type of radiation shielding seems like a natural for a mission with astronauts.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
fyi you got your equations wrong -- you meant mass flow rate (aka m_dot) times exhaust velocity gives you thrust .. notice that the units on this end up correct (mass*distance/time^2) whereas the mv^2 gives us Joules (in metric) aka energy - infact, you might recognize 1/2 mv^2 from highschool physics.
.. even if they were made out of "unobtanium."
Also - as far as light speed goes - yes, I guess your particle mass would approach infinity, but then so would your power requiremnent (its not just a voltage difference), wouldn't it? And even a nuclear reactor can't provide inifite power.
Also, generally ion engines have charged plates to accelerate the ionized fuel, these would wear out pretty quickly if you were bombarding them with infinitly massize particles moving at light speed
Finally, practically speaking ion engines CANNOT function in atmospheres - the ambient pressure of an atmosphere will "out push" the pressure produced at the mouth of the thruster by the thruster. With a nuclear reactor - I don't know - I do agree that it'd be nice if someone would cough up the cash for that...
It will happen. You don't need friction, you just need ass-kicking "manouvering thrusters" on every side.
You can have your stupid tie fighters. I'm waiting for the xwing with "shields". Who the hell builds a space fighter and relies on non-regenerating "armour". Although, maybe I'd be up for the TIE++ model depending on how long shields take. You know, the one made out of carbon nanotubes with backup nanobot repair packs.
You can pull ions straight out of space. No need to bring your own fuel. Think of it like a submarine powered by water. That's also why they're good for long-term missions. Infinite fuel. You can just leave the pedal to the metal the whole trip. Granted, your acceleration sucks, but it doesn't stop.
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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Yeah? Well, for your information TIE Fighters don't have any kind of shielding, and only 1 out of 4 survive to retirement. They're fast, and they're extremely lightweight, and *very* maneuverable, but they don't have any shielding. The pilots fly in a spacesuit, and that's their atmosphere. None of the pressurized bullshit X-wings with their shielding. That's how come the TIE fighters outran the X-wings and even flew circles around them at the Death Star. It's also why if you hit one it usually blew up, whereas an X-wing could sustain a lot more damage.
Like what I said? You might like my music
Deep Space 1 certainly did not fail (who in their right mind would send a multi-million dollar probe up without testing it first?!) Here's proof.
Deep Space 1 ion engine lab videos Pictures of the DS1 project (scroll down for ion engine)
DS1 was one of the most successful missions that NASA ever had. If you doubt me, you can look at the site...Official DS1 site
They extended the mission MULTIPLE times, and even landed it on an asteroid (yes, landed, very softly too) This European mission isn't even worth mentioning. They're going to map the moon, whop-de-freaking do. The only reason it's getting press is because of the ion engine, which if the press cared about the American space program they would have reported that NASA has already succesfully untilized ion engine technology in space for hundreds of days in a row. It was shut down after hundreds of days of use (and after it had completed its mission). Then they restarted the engine (unprecedented!) by 'shaking it up' with the gas maneuvering jets. You've misread your space history, jd.
If the ion propulsion spits out lots of positively charged ions. What happens to the surplus electrons ? Will the spacecraft build up a negative elecrical potential ? Will this cause trouble with discharges if you try to land on something when you get where you are heading ? Is there a way to dispose the electrons ?
Man, if that was such a simple matter I'd be to Alpha Centauri after all the bean burritos I've had in my time...
--------
If I can own an idea, does that mean I can legally claim some portion of your soul once I tell you that idea? Or even if you just come up with it on your own? Heck, who needs contracts written in blood...
"What in the name of Fats Waller is that?"
"A four-foot prune."
The 15 month travel time isn't too appealing. But with the cheap cost and simpler propulsion system, the trade-off is acceptable.
The nifty thing is that ion drives is possible with practical applications for planetary exploration.
!@#$% whole-grain cereal. When I want fiber, I eat some wicker furniture. - G. Carlin
The quantity of movement (m * s) is preserved in the system. "s" stands for the speed *vector*, and "m" for the mass.
Therefore, if you eject something out of the rocket, because the quantity of movement is preserved, you have a "delta s" generated that pushes you in the opposite direction.
Since rockets eject small quantity of material (compared to their mass), they need to eject it at a very high speed so that the rocket gains the opposite quantity of movement.
This is linked with acceleration (which is a variation of speed) but not really as you explained it: What matters is the ejection speed, which creates a delta speed in return.
If we assume the rocket's mass is M and the quantity of particles ejected at instant t is dm, at speed s, and we project the vectors on the propulsion axis, then we have:
0 = dm * s - (M - m) * ds -- Quantity of movement preserved, i.e. = 0
"ds" is the variation in speed of the rocket due to the ejection.
So: ds = (dm * s) / (M - dm)
The fastest "s" is, the higher ds, which is the acceleration gained.
Note that this is true only in space. An airplane ejects matters through its reactors continuously, but we are not in space: there is a reaction force exerced by the air within which the airplane moves. That's why airplanes tend to fly in the higher portions of the atmosphere, were there are less molecules (but still a sufficient supply of O2 molecules, since airplanes are not rockets: they don't embark the oxygen necessary for the combustion).
Ion Engines, 0-600,000 in 2.2 light-years!
What is special about xenon? How much does one need to for a mission like this?
NASA [...] can't even afford to replace the bearings on the ancient platforms that carry the Space Shuttles to the launch pad.
Actually, they repaired and replaced the bad bearings in the JEL (jacking, equalization, and leveling) cylinders before they allowed Atlantis to launch within a month of discovering the problem during an effort to refurbish and maintain systems which hadn't been taken apart since the construction of the machines in 1966. That's pretty good considering that they only had 9 spares for 34 worn and broken bearings. They fixed it back in September of 2002 after discovering it in August of 2002.
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
I know I've seen NASA projects testing a NASA Ion engine in space. I think it was Deep Space 1, which looks like it was started and finished years ago. They also made a flyby of a comet 2 years ago similar to this European probe's flyby of the moon. Seems to me that the moon is an easier target to fly by than a comet. So, this doesn't look like anything new to NASA.
Here's a FAQ on what they're doing with it and why most NASA projects don't want to use it:
NASA FAQ About Ion Propulsion
It could be simply a question of money -- if you can afford to use tried-and-true technologies, why use slower, riskier technologies when you really REALLY have to produce results? But, like they say in the FAQ, if they can prove the technology for long haul missions, that's where it makes sense. They even say specifically that for short missions like to the moon it doesn't make sense (look at how long it'll take that European probe to get to the moon -- 2005?).
Hmm, I don't remember seeing Deep Space 1 news like this on Slashdot -- I had to see it on PBS. Could it be bias or just ignorance? (correct me if I'm wrong, but even a search for "Deep Space 1" on Slashdot didn't produce anything relevent)
"Look, Houston. That SMART-1 probe is heading for the moon!"
"That's no moon..."
(Obligatory Star Wars quote)
Why would anyone mock the Europeans. In a very real sense, the US and Russian space programs are rooted in the very-successful German rocket program anyway, since the two superpowers divided up the German scientists after the war, forgiving any Nazi tendencies they may have had to form their respective programs.