Ion-Propulsion Craft Reaches The Moon

Peak of eternal light by Rei · 2004-11-15 11:40 · Score: 5, Informative

I think what is most interesting is one of the destinations they're going to visit - the peak of eternal light. Perfect spot for a moonbase - constant sunlight instead of 2 weeks of light and 2 of darkness, water ice likely in nearby craters, and temperatures warm enough that you might be able to get by with passive solar heating alone.

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Re:Peak of eternal light by binarybum · 2004-11-15 11:48 · Score: 5, Interesting

man, screw your moon base. Perfect place for a five-star resort. This sounds like prime realty. The europeans should stake a claim to it and auction it off as land for when the moon is colonized. The price this would go for would probably fund a colonization project, oh and a moonbase - somewhere else.

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Re:Peak of eternal light by RebelWebmaster · 2004-11-15 11:51 · Score: 5, Informative

I'm pretty sure there are international treaties banning any country from claiming extraterrestrial land for their country.
Re:Peak of eternal light by Naffer · 2004-11-15 11:56 · Score: 2, Insightful

I'm also pretty sure that no one could do anything about it if the U.S. built a base and claimed to own 10 miles in every direction around it.
Re:Peak of eternal light by AstroDrabb · 2004-11-15 12:01 · Score: 2, Insightful

Sure they could. China could send up a "scientific mission" that just happens to fail and crash into the US Moon base. Do you really think the USA would start WWW (III/IV/V) over it? Humm, if the president at that time happens to be a Bush, maybe "we" would.

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Re:Peak of eternal light by uncoveror · 2004-11-15 12:19 · Score: 4, Funny

No one on earth could do anything about it, but not everyone who goes to the moon is from earth. The Zhti Ti Kofft would probably destroy any U.S. base in no time, or at least conquer it, and say ALL YOUR BASE ARE BELONG TO US!

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Re:Peak of eternal light by yobbo · 2004-11-15 12:44 · Score: 2, Insightful

You honestly think the US will remain the leading superpower forever?

You poor thing.
Re:Peak of eternal light by Jaywalk · 2004-11-15 13:11 · Score: 2, Funny

I'm pretty sure there are international treaties banning any country from claiming extraterrestrial land for their country.
Sorta. You're probably thinking about the Lunar Treaty. While that treaty only prohibits the actions of states, I doubt that a private industry would be able to claim moon land with any authority. Still, Article 9 specifically grants the authority to build moon bases provided "that they do not impede the free access to all areas of the moon by personnel, vehicles and equipment of other States Parties conducting activities on the moon."
Sure, you can build your luxury hotel, but you're never going to be able to keep out the riff-raff.

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Re:Peak of eternal light by phoenix321 · 2004-11-15 15:00 · Score: 4, Insightful

Of course there's no army to back this up. But if you built a base on the moon and claim anything inside plus 5 km around the perimeter your own property, it *should* be yours.

It's as simple as that: if you made new land habitable, it should be yours. Maybe I'm a little romantic here, but making some land habitable comes first, then it becomes your property, then you defend it against possible intruders.

As long as there is enough land left on the moon, there will be no conflicts, if the people involved have the slightest hint of moral obligatons left. What they may or may not have anymore, considering this will be 20 years from now at a minimum.

In general, humans all alone on a vast amount of land, totally devoid of people, in a situation of need and struggle, they tend to build friendly relationships instead of murdering each other for a piece of land. Supply and demand. If there's enough resources, land in this case, left, people don't value that land high enough to commit crimes against their moral standards. Example: Australia. Even outlaws built a society, because they couldn't survive otherwise.

Sooner or later, people will fight their wars in space, of course. But not as long as there's millions of square kilometres left for anyone to take.
Re:Peak of eternal light by JudgeFurious · 2004-11-15 16:33 · Score: 3, Interesting

Well of course nobody thinks the US will remain the leading superpower forever. Nobody who gives it any thought at least. At one point damned near ever real "power" on the earth was located in Europe. Now there's not a single nation in Europe that equals the United States. Together they do the job quite nicely though.

That's just it. Despite what we've seen from the former USSR there is life after being a superpower. Most Americans aren't living under the impression that the ride's going to last forever and only the small percentage of real paranoids think it has to at any cost.

I can't wait for us to return to being one of the pack so to speak. Then maybe our leaders wouldn't feel like it's necessary to station troops all over the planet. A military that can protect the United States is fine by me. An economy in the upper half of the world is more than many could ask for. Damn I'd like to see us get out of the world police business and back to the "working on making America better" business.

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Re:Peak of eternal light by hey! · 2004-11-15 16:40 · Score: 2, Interesting

It's as simple as that: if you made new land habitable, it should be yours. ...

As long as there is enough land left on the moon, there will be no conflicts, if the people involved have the slightest hint of moral obligatons left.

The words you are looking for here are: Lockean proviso. According to Locke, it is permissible to privatize a resource that you improve, provided you leave as much of the same (unimproved) quality for others. For example, you can privatize an oasis in the desert, so long as it is not the only one within reach of a caravan route.

Of course Locke then went on to argue that money changes this basic moral prinicile, but that's a story for another day.

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Re:Peak of eternal light by Dr.+Spork · 2004-11-15 17:58 · Score: 2, Interesting

I think you're right, and I know it's off topic, but though I detest our present foreign policy, I don't want some other country to be a superpower either. Well, maybe some sane country like Norway or Canada, but China or India seem far more likely candidates.
I think after USA falls apart, the world should get together and have a "no superpowers" rule. But then again, there were no superpowers at the 70 years ago, and things didn't turn out so well. Europe sort of punched itself out, somebody else took over. We might not be far from that right now.
Re:Peak of eternal light by sonicattack · 2004-11-15 18:45 · Score: 2, Interesting

Well, maybe some sane country like Norway or Canada,

And just how long would they remain "sane" when living with the status as "superpower"? How long before they too turned paranoid, or pissed off somebody and really got something to worry about?

Has there been studies on how even being targeted with nuclear weapoins for prolonged periods affects human psychology, and in the extent, foreign politics?

There was said something about how power corrupts.... Perhaps every state should have plans for how _not_ to grow too large or powerful. An international agreement to keep world domination in check. (No, a perpetual state of war isn't it. :)
Re:Peak of eternal light by LucidBeast · 2004-11-15 22:25 · Score: 3, Informative
Some comparisons
- Currently European Union has more citizens (~400M) than United States (~280M), but US I think has younger population. Europeans aren't having enough immigration or kids.
- European Unions economy is a bit bigger than US economy, but US has still more GDP per capita. US spends larger portion of its GDP on Defence (or Offence I guess now days), also Europeans have longer vacations and shorter work weeks that eat up the GDP a bit. Quality of life for citizens is hard to measure.
- Europe doesn't have unity on what it should be: lose pack of nations concentrating on economic issues or more of a federation counter balancing United States.
- All Europeans have health care of some sort. 40 million US citizens don't
- EU citizens have higher life expectancy than US citizens despite US spending more on health care per capita
- EU kids score better in math and science than US kids
- EU economy has been growing slower than US economy
I'm don't think US is a failing empire, but unless the emphasis in US politics changes from gay rights, abortion, religion vs. science and god in pledge I think it will run into trouble. Also the huge military emphasis and spending is a taxing even to a rich nation like US.
Also Europe has its problems and it's not a Utopia, so please don't take this comparison that way.
Re:Peak of eternal light by JudgeFurious · 2004-11-16 02:37 · Score: 2, Insightful

I don't really care how it happens (The US gets weaker or the rest of the world becomes stronger) because in the end it's the same thing.

I simply believe that a US military presence in countries like South Korea, Japan, and of course Germany is no longer needed. Prior to WWII we didn't have soldiers stationed in those countries (though of course we had them in the Philipines as we owned them at that time) and now that things in those areas are more than stable I see no reason to continue it.

Sure North Korea is a friggin nightmare but honestly isn't that the problem of the nations in that particular region? What keeps their army from coming south again? Is it the physical presence of US troops stationed in the south? I no longer think that's true. The players in that part of the world are interdependant now. NK's biggest (and maybe only) friend is China. China's biggest market is the US. SK's biggest friend is of course the US and economically we're tied tightly to China. Nothing is going to happen and if anyone should be hard at work keeping a lid on Kim Il it's China, not the United States.

Japan and Germany can easily defend themselves and both do. The defense budget in the US has been exceedingly large for far too long. I'm not espousing isolationism either. One can be involved in the affairs of the rest of the world to a reasonable and not inflamatory degree without keeping soldiers around the globe. The money spent doing this would be better spent elsewhere.

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Re:Peak of eternal light by virtual_mps · 2004-11-17 01:33 · Score: 2, Interesting

The players in that part of the world are interdependant now. NK's biggest (and maybe only) friend is China. China's biggest market is the US. SK's biggest friend is of course the US and economically we're tied tightly to China. Nothing is going to happen and if anyone should be hard at work keeping a lid on Kim Il it's China, not the United States.

You seem to be laboring under the misconception that wars begin for rational reasons. Do you know who Germany's largest trade partner was prior to WWI? France--and their economic "interdependency" did nothing to avert that war. Both countries burned themselves out and the conflict pretty much ended European dominance in world affairs. Was that war rational? Wars start because some leader is too stupid, scared or short-sighted to not attack somebody. The reality of the situation is that if someone decides for some stupid reason to launch an attack on, e.g., South Korea, it will be too late after the fact to say "gee, we should have had some troops there".

better article by teridon · 2004-11-15 11:41 · Score: 4, Informative

Nature has a better article here.

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Re:better article by macdaddy357 · 2004-11-15 12:04 · Score: 3, Funny

That one's pretty good, but I think this one says it all.

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How ya like dat?
Re:better article by nofx_3 · 2004-11-15 13:29 · Score: 2, Informative

Only in an environment with no or little gravity. The problem is that from the surface of earth there is friction and gravity to deal with. Ion propulsion does not have a high enough specific impulse to get something as massive as this probe (or really anything for that matter) into orbit. If you were to actually read the acrticle you would see that it reached orbit on an Ariane IV (a traditional liquid fueled rocket) launched from French Guiana.

-kaplanfx

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Is it regular speed? by xanthines-R-yummy · 2004-11-15 11:42 · Score: 4, Interesting

Does anyone know how the trip time compared other expeditions? I realize that the longer the flight, the more efficient and speedy this method would be, but I was just trying to get an idea of how fast this thing moves. Could cryogenics and this propulsion technology together land humans on other planets?

Re:Is it regular speed? by Rei · 2004-11-15 11:52 · Score: 5, Informative

Well, apollo took a little over 3 days to accomplish what this craft took a year to do. And it's not neessarily "the longer the flight, the more efficient and speedy this method would be". It's all about ISP. The faster the "exhaust" leaves the craft, the less mass of propellant you need to achieve a given delta-V - and it falls off fast.

In fact, ion drives tend to be rather energy-inefficient. However, they get their energy from electricity, which is renewed either by solar or RTG energy. Since RTGs are extremely energy-dense compared to conventional fuels, and solar cells constantly take in more energy, the penalty for a large amount of electrical waste and much, much larger propulsion system (for a given amount of thrust) is dwarfed by the benefits in terms reduced propellant mass.

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Re:Is it regular speed? by centauri · 2004-11-15 11:54 · Score: 5, Interesting

Could cryogenics and this propulsion technology together land humans on other planets?

No, especially if you're aiming for extrasolar planets. Ion engines are good for a small payload that can take its time getting to where it's going. Humans (even those in some kind of imagined stasis) need something with a higher thrust to get where they're going in a reasonable time (ie, before cosmic radiation carves up their DNA, or a micrometeor holes their lifesupport system).

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Re:Is it regular speed? by Metryq · 2004-11-15 11:55 · Score: 2, Informative

Ion propulsion would be the last drive I'd consider for human transport. It is extremely low thrust, but can maintain drive for a very long time. Take a look at nuclear thermal rockets at nuclearspace.com. The book TO THE END OF THE SOLAR SYSTEM is an excellent primer on the technology and history.

I think it was the TOS Trek episode "Spock's Brain" where Scotty commented on an ion-driven ship, "they could teach us a thing or two!" Right.
Re:Is it regular speed? by purfledspruce · 2004-11-15 11:57 · Score: 4, Interesting

The high radiation environment of space keeps us from using this method for humans.
However, it would be quite useful to use this technology to bring cargo to the Moon for possible astronauts to use. For instance, it's possible to deploy an entire habitat--crew quarters, energy producer, perhaps even in-situ resource production ("mining" water-ice for oxygen and hydrogen to feul your return vehicle)--all before we launch humans on a high-energy tracjectory that will get them there in three days, thus avoiding high radiation exposure.
You could do similar things with Mars. Here's a reference done by the Revolutionary Aerospace Systems Concepts part of NASA:
OASIS
It will take a suite of technologies to get safely to other planets, and possibly another suite of technologies to get back.
Re:Is it regular speed? by Rei · 2004-11-15 12:40 · Score: 2, Interesting

No, nowhere near light speed. SMART-1's ion drive, for example (which was actually a Hall effect thruster, which is a little less ISP-efficient, but not that much) launched xenon atoms at 16,000 m/s. Deep Space 1 did the same at 35,000 m/s. Light travels at 299,792,458 m/s. It's not realistic to go up to relativistic speeds with an ion drive.

Acceleration is painfully slow, but again, that's not necessarily a requirement of an ion drive. It may prove to be a practical limitation, however; we'll have to see.

You can make a (very inefficient) ion drive at home on earth with commodity items - they're called "lifters" (an ironic name, since they typically can barely lift themselves). Lifters work through ionization of air via coronal discharge.

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Re:Is it regular speed? by Rei · 2004-11-15 12:49 · Score: 2

Sorry... sometimes I forget that many people here aren't very familiar with rocketry.

ISP is specific impulse. Roughly, ISP in a general (Earth) context is velocity/~9.8. So, given a hydrogen-oxygen rocket with an ISP of 450, this means that its exhaust is leaving at 450*9.8=4410 meters per second, or roughly half of the velocity for a LEO orbit. Compare this to a good ion drive which may give you ~40,000 m/s exhaust (still far from the ~300,000,000 m/s speed of light, mind you).

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Re:Is it regular speed? by bcrowell · 2004-11-15 12:50 · Score: 5, Interesting
Apollo 11 took 73 hours from the burn that took it out of Earth orbit to the burn that inserted it into lunar orbit. This is actually very close to the time it would take to free-fall to the surface of the Earth from a distance equal to the radius of the moon's orbit. This is pretty much always the case with chemical rockets, which work by doing short burns followed by very long periods of free fall: the time to get there is the time it takes to orbit from here to there. To go to Mars, you can use Kepler's laws, and you find that the time to get to Mars in an elliptical orbit is 0.70 years.
The problem with getting to Mars is fundamentally the radiation. If you send astronauts to Mars on a 0.70-year orbit, without any shielding against penetrating radiation, their radiation dose ends up being on the same order of magnitude as the dose that kills you. This is Not Good :-) There is a variety of ways to get around this:
1. Use electromagnetic shielding. (There was recently a Slashdot article on this. The idea is to use a quadrupole field, which discriminates between high-mass and low-mass particles.)
2. Use really thick material shielding. This requires either a really really really thick layer of rock, steel, ... (very heavy), or a really really thick layer of liquid hydrogen. Either way, it's a lot of mass.
3. Cut the trip time dramatically.
Solar-powered ion drive could make method #2 practical, because it would theoretically allow very large masses to be moved around without having to lift huge amounts of propellant off of the Earth's surface. However, a ship with a nuclear reactor aboard (not just a passive RTG) could accomplish both #2 and #3.
Fundamentally, I don't see the justification for sending humans to Mars in the forseeable future. The really exciting science task would be to find out of there is unicellular life on Mars (with a positive result probably qualifying as the most important scientific result of the last 200 years). This can be accomplished with an uncrewed sample return mission.
Want to send humans to Mars? Great! Please dream up either (a) a valid scientific reason, or (b) a valid commercial reason. I don't think either exists presently, and I don't think either will exist within the next 100 years.
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Re:Is it regular speed? by Rei · 2004-11-15 13:02 · Score: 4, Interesting

The problem with all shielding methods proposed is that none that are lightweight handle GCR well. Electromagnetic shielding, mind you, does have some very promising applications concerning the Van Allen belts and other lower-energy particles. Right now, it looks like either liquid hydrogen or heavily saturated plastics (HDPE, for example) are going to be the best way to shield a craft on long trips.

While I agree that there *currently* isn't a good reason to send people to Mars, I think that once we can demonstrate some cost-effective mix of ability to mine low-G bodies, grow realistic amounts of food outside of Earth, create bulk raw structural materials outside Earth, and to produce fuel outside Earth, there is ample reason to work on colonizing Mars. Not only would being able to do these reduce the costs of operation, but even high costs could be justified by the future-potential of using Mars as a triangle trade with Earth and the asteroid belt (one of the few things I agree with Zubrin on). So, I would argue in favor of working on the technology with the goal of eventually having it become a realistic course of action.

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Re:Is it regular speed? by djmurdoch · 2004-11-15 13:35 · Score: 2, Interesting

Other people have pointed out that the Apollo missions got there in much shorter times.

However, an interesting oddity is that the SMART mission averaged a significantly higher speed than Apollo did: It spiralled out from the Earth, and travelled around 80,000,000 km, according to the Nature article someone posted. Apollo went to the moon pretty much by the shortest route.

Doing the math, I find the SMART average speed was around 8500 km/H, while Apollo averaged around 5500 km/H.
Re:Is it regular speed? by spike+hay · 2004-11-15 14:29 · Score: 2, Insightful

There is no friction in space so inertia will carry they ship at a constant velocity, that is unless its constantly accelerating as is the case with the Ion drive. It would take a long time but you should eventually be able to reach near relativistic speeds seeing as you are accelerating constantly albiet at a very slow pace.

Unless you want to carry a few solar masses worth of xenon, you cannot get to relativistic speeds with an ion engine. The exhaust velocity of DS1 was 30km/sec. Now, C is 300,000 km/sec. This means that the stuff travelling out the back of the ion thruster is going a mere 1/3000 of lightspeed. Using Newton's laws, you can see that it is completely impractical to reach such a speed with an ion thruster.

A better idea would be a laser sail, in which a multi-terrawatt orbital laser would propel a spacecraft many miles wide composed of gold film. Due to the fact that it would carry no fuel, it could reach near lightspeed. Other, slower options, include very advanced fusion engines, although that might not be that efficient in practice.

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The latest score just in... by Electronik · 2004-11-15 11:42 · Score: 2, Funny

SMART-1
BEAGLE-0

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Re:The latest score just in... by uncl_bob · 2004-11-15 12:12 · Score: 2, Funny

Why would it? Beagle = Mars, SMART = Moon.

I don't get it by centauri · 2004-11-15 11:42 · Score: 3, Insightful

this method of propulsion could be ideal for travel in near-weightless space as it does not require any combustion to occur

What were you trying to say here? That combustion rockets are not a good way to travel through space? Maybe they're not the best, but it's going to be some time before anyone seriously considers getting people to the moon with ion engines.

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Re:I don't get it by Headw1nd · 2004-11-15 12:05 · Score: 5, Interesting

Ok.. the reason this is noteworthy, despite it's lethargic speed, has to do with reaction mass. Ion propulsion and rockets are similar in that both require reaction mass for propulsion- the craft goes forward because something goes back. The speed which the craft goes forward is proportional to the speed that something is ejected out back. Ion drives have ejection speeds far above that of conventional rockets, thus are far more efficient in their use of their propellant.
So?
So this is crucial on the long haul. With a reaction drive, when you run out of reaction mass, you're done. The craft becomes inert. The trick here is that the saturn V was out fuel within 15 minutes, wheras this craft is still accelerating a year later. Concievably, it could run for another year, or a dozen. (I don't know how much reaction mass it has) An ion drive craft might be made that could with enough reaction mass for an interstellar voyage, where a chemical rocket could not. (esp. considering the mass needed to decelerate at the ead!)
Re:I don't get it by Headw1nd · 2004-11-15 14:47 · Score: 2, Insightful

A chemical rocket could reach another star, but in talking about a voyage, a shorter timespan is implied. Say something in the less than 1,000 year range. For this you need more sustainable acceleration.
To showcase what I mean, the current fastest human object is Voyager 1. It was launched via chemical rocket and is currently traveling at 3.4 AU/year. The closest star, Alpha Centauri, is currently 275725 AU away. While something that speed would eventually reach another star, there would be little point in sending it there.
Re:I don't get it by Anonymous Coward · 2004-11-15 16:36 · Score: 2, Informative

You will never reach light speed, but you can still outrun light, as long as you start accelerating at more than a distance of c^2/A away from the light source, where A is your proper acceleration and c is the speed of light (assuming constant proper acceleration). Consider this spacetime diagram; any light emitted beyond the indicated Rindler "event horizon" (blue 45-degree line) will never intersect the worldline of the accelerated observer (red hyperbola).

So when do we get to see the US flag? by rsborg · 2004-11-15 11:42 · Score: 4, Funny

On one hand, showing the US flag on the moon would make for very good press...

[conspiracy] On the other hand, if they can't find it... [/conspiracy]

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Re:So when do we get to see the US flag? by fredrik70 · 2004-11-15 14:13 · Score: 2, Informative

Well, the flag which the crew from apollo 11 apparently got toasted a bit, IIRC the planted the flag a bit further away on the later missions

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Re:So when do we get to see the US flag? by apanap · 2004-11-16 02:02 · Score: 2, Informative

There are mirrors left on the moon by the Apollo 11 astronauts that were put there to be able to measure the distance to the moon by laser. It's mentioned here for example. But the conspiracy theorists won't listen to that...

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It REALLY Ain't warp speed by guitaristx · 2004-11-15 11:45 · Score: 5, Interesting

Considering that Apollo 8 made it around the moon in less than a week, and this mission took over a year, we're not dealing with lots of speed here.

I'm interested in seeing some comparisons with project cost, energy consumption, etc.

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Re:It REALLY Ain't warp speed by Ianoo · 2004-11-15 11:57 · Score: 4, Insightful

Yes, but Apollo 8 didn't accelerate all the way, and couldn't accelerate all the way from here to halfway to Alpha Centauri. You'd get there a lot faster on ion drive.
Re:It REALLY Ain't warp speed by WillWare · 2004-11-15 12:28 · Score: 3, Informative

Apollo 8 ... couldn't accelerate all the way from here to halfway to Alpha Centauri. You'd get there a lot faster on ion drive.
To maintain the acceleration, you need sunlight hitting the solar panels. When you get that far out, the sunlight's going to be very weak. By then you might have picked up plenty of speed (I haven't done the math) but at the halfway point you won't have the acceleration you had near the inner planets.

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How long will it take to reach Mars? by jerichohol · 2004-11-15 11:46 · Score: 4, Funny

Warp 0.0001 more like it, Picard would say"E....N.....G....A....G......E"

Re:How long will it take to reach Mars? by adam31 · 2004-11-15 12:07 · Score: 4, Funny

"Prepare ion thrusters for - Retarded Speed!"

wrong link by Anonymous Coward · 2004-11-15 11:47 · Score: 5, Informative

it's http://www.esa.int/ not http://www.esa.in/

Re:Warp ? by uberdave · 2004-11-15 11:47 · Score: 2, Funny

I guess that would make it impulse, then :-)

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"I'm not impatient. I just hate waiting." - My Dad

Plasma technology is the space enabler by QuantumG · 2004-11-15 11:49 · Score: 5, Interesting

Although it's called an "ion engine", it's really just the first step in the progression of plasma propulsion. Next up we have the VASIMR which they've been talking about testing on the space station. It can produce slow thrust like an ion engine, or it can produce hard thrust like a chemical rocket. You can power it with solar panels, or you can power it with a nuclear reactor. Eventually, almost the exact same design will be used in fusion rockets, and possibly even antimatter rockets. Then we're in Startrek country with plasma power distribution and ships which you can actually live and work on.

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How we know is more important than what we know.

Re:Plasma technology is the space enabler by WolfWithoutAClause · 2004-11-15 12:22 · Score: 3, Informative

Next up we have the VASIMR ... it can produce hard thrust like a chemical rocket.
'Fraid not. To do that requires an enormous, lightweight, electrical power source. No current powerplant, solar, nuclear, chemical or other can provide enough power to generate high thrust when used with VASIMR.
VASIMR is a wannabe fusion power drive. Trouble is, fusion doesn't work well enough right now to use it for this; and they are stuck with trying to powering it the old fashioned ways. It works, but not noticeably any better than ion drive- if you were to get VASIMR to work with a new power supply, you can pretty much just gang up any of the existing ion drive thrusters and get about the same thrust.
VASIMR has theoretical advantages of being able to vary the exhaust velocity to increase the thrust, but even on the lowest settings I've seen them talk about, ion drives usually give better thrust.

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Re:Plasma technology is the space enabler by DeputySpade · 2004-11-15 15:01 · Score: 2, Insightful

s/weight/mass/g

We _are_ talking about space here, afterall.

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Boeing has some power... by domenic+v1.0 · 2004-11-15 11:52 · Score: 4, Informative

Boing has developed the PAS-5, the world's first commercial satellite with an ion thruster.

This is not the first ion drive... by meringuoid · 2004-11-15 11:52 · Score: 4, Informative

... JPL's Deep Space 1 demonstrated the potential of such an engine back in the 20th century. Now we're seeing the first missions to rely on ion propulsion.

It'll be interesting to see, if the Pluto probe ever flies, whether that uses ion propulsion. An ion drive could really make a difference on such a long-haul flight.

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Cheap Technology! by jd · 2004-11-15 11:57 · Score: 4, Funny

Give me a Bussard Ramjet any day! Well, that and an extremely good handbrake.

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Re:Cheap Technology! by WolfWithoutAClause · 2004-11-15 12:38 · Score: 2, Informative

Actually, analysis of Bussard Ramjet showed that it is a good handbrake!
Inspite of early promise it turned out that the thrust/drag of the ramjet against solar wind and interstellar gas turned out to be below unity. That's bad- you don't go anywhere.
This lead to a concept called M2P2, which is an 'inflatable' plasma. You turn it on and it expands out to a few tens of kilometers, the solar wind pushes on it, and a few months later you are leaving the solar system at high speed, dragged along by the plasma. Basically they ditched the drive system, and just used the collection field.
It worked in a small scale lab test, but nobody knows whether it will really expand out to a few tens of kilometers, and there were a few potential problems, such as tending to vapourise the vehicle due to the very high temperatures of the plasma, still it shows some promise, it's similar to the way the Earths magnetosphere operates.

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-WolfWithoutAClause
"Gravity is only a theory, not a fact!"

TIE Fighers? by ecliptik · 2004-11-15 11:57 · Score: 5, Informative

Isn't this how TIE Fighers from Star Wars worked? Their wings were solar panels, and TIE stood for Twin Ion Engine.

Re:TIE Fighers? by jfengel · 2004-11-15 12:09 · Score: 4, Funny

That's right. What the movie doesn't make clear is that it was sped up by a factor of 10,000, because solar panels that size result in only a trivial amount of thrust.
Re:TIE Fighers? by mikael · 2004-11-15 12:42 · Score: 4, Funny

That's right. What the movie doesn't make clear is that it was sped up by a factor of 10,000, because solar panels that size result in only a trivial amount of thrust.

No, the TIE fighters had a large bank of 48 car batteries which were kept topped up by the solar cells. Each TIE fighter had to charged up from the mains at least once every 48 hours, otherwise the battery would run flat, and you'd be stuck in space. In that case, the only way to start the engines was to plug an R2D2 unit into the cigarette lighter socket.

--
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
Re:TIE Fighers? by Tablizer · 2004-11-15 13:01 · Score: 3, Funny

Isn't this how TIE Fighers from Star Wars worked? Their wings were solar panels...

"Luke, you may get away today, but in 12,000 years my total thrust will eventually exceed yours, and you'll be MINE!" -- Darth "Quickie" Vader

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Table-ized A.I.

Sharper Image by nick_davison · 2004-11-15 11:59 · Score: 2, Funny

Anyone who's anyone knows Sharper Image have been selling these for years.

There's really no end to the crap Sharper Image can add ions to and double the price for. It only stood to reason they'd release spaceships with them too. ;)

You'll find them in their catalogue next to the negative ion vacuum cleaners, negative ion air purifiers, negative ion hair driers, negative ion bikini zone razors, and negative ion pet hair brushes (the scary thing is I only made one of that entire list up).

Science writing at its best by peggus · 2004-11-15 12:03 · Score: 5, Informative

The engine does not combust fuel; rather it splits atoms with electricity to get ions, accelerates them at high speed, and then ejects them, driving the spacecraft forward. SMART-1 generates its electricity by converting sunlight with outsize solar arrays that give the spacecraft a 45-foot wingspan.

Brilliant science journalism there. If the smart probe was splitting atoms it wouldn't need solar panels. Not to mention you don't need to split atoms to get ions.

That reminds me of the article that was written on some research I was involved with. We were pulsing cells with high potential electric fields. The field strength was measured in MegaVolts per meter due to a very small gap between the electrodes, the actual voltage was only a kilovolt or so (over a 300ohm load for 5-15 ns). The journalist / engineer-reject thought that megavolts sounded really big and took it upon herself to proclaim that our pulse generators could power a whole city. Moan, groan....

Re:Science writing at its best by peggus · 2004-11-15 14:02 · Score: 2, Funny

True.
And technically our pulse generators could power a city, for a very very short period of time.

How is weightlessnes relevant? by mowler2 · 2004-11-15 12:05 · Score: 5, Interesting

I dont understand why they talk about the probe being (near) weightless in space in the same context as the engine beeing useful in space?

No matter where the probe is, it has got the same mass, and hence the same inertia. Low-thrust engines work good in space because of no friction and often no requirement on quick travel (if it is a non-manned spacecraft). On earth an ion engine would never work for several reasons, one beeing friction against air and ground, but none of them has to do with the weight of the vechile/probe?

Or have I misunderstood something?

Re:How is weightlessnes relevant? by jmichaelg · 2004-11-15 13:04 · Score: 2, Insightful

I think they were implying that you couldn't use one of these engines to get off the earth's surface. The thrust they generate is on the order of the weight of a single sheet of paper. If you don't have to fight earth's gravity to get the craft moving, you're set. If you're trying to get off-planet, you're not going anywhere.
JPL has an open house every year. A few years back, they were in the middle of a multi-year burn test and during the open house, you could see the engine's blue glow as it sat there chugging out ions into a vacuum chamber. It was totally silent (vacuum has that effect...) and the exhaust looked like it came off the front page of Analog.
Re:How is weightlessnes relevant? by mowler2 · 2004-11-15 14:29 · Score: 2, Informative

>not for e.g. atmospheric flights.

In atmospheric flights you also have problem with air friction.

>you're mixing up mass and weight.

The mass of the probe is the same in a zero-g environment, or on jupiter - it is the weight that is different, we both agree on that.

However, I still dont see why weight, in it self, is (always) relevant for the acceleration of the probe. When we calculate the resulting acceleration from the engines we only consider the mass of the probe and the engine thrust. Now imagine if we have the probe on earth in a vacuum tube floating on some zero-friction surface or magnetic field (we have force equlibrium). Then if the engine are turned on, they would accelerate the probe as much as they do in empty space even though the probe has weight, right? (now the gravitational force is counteracted by the force of the magneticfield, instead of the centrifugal force in orbit)

Re:ideal? by Anonymous Coward · 2004-11-15 12:06 · Score: 2, Informative

In case you're not clear about this... SMART1 was built by ESA, not NASA. With that out of the way... SMART1 costs less than $100M, which is pretty cheap. It was the smallest of 3 payloads on an Ariane 5 rocket. So, this is a small, R&D style mission, very much unlike what happened in 1969.

Ion drives are great in some situations, because they give you a lot more thrust (over time, of course) per pound, then chemical drives. I believe they're about 5 times as efficient. Thus, if you're not in a hurry, this is indeed useful. And NASA used an ion drive for it's Cassini mission to Saturn too...

NASA announces it will outdo the ESA by i41Overlord · 2004-11-15 12:09 · Score: 5, Funny

"After hearing the news that the ESA's slow ion-powered probe has entered Moon orbit after a record-long 13 month voyage, NASA has announced that it will launch an even slower probe that propels itself by gliding on a trail of its own mucous."

Re:Not the best source in the world. by MillionthMonkey · 2004-11-15 12:52 · Score: 2, Informative

Isn't the Washington Times the same paper that is owned by the Moonies?

Yep... if you're uncomfortable getting your news from Rev. Moon (a.k.a. God himself) there are plenty of non-cult-affiliated links for this story.

Re:ideal? by polyp2000 · 2004-11-15 12:54 · Score: 2, Informative

While you are correct in saying that for such a short distance it seems somewhat a long time to get from point A to point B to use such a propulsion system to travel a huge distance it becomes a much more viable proposition. In terms of acceleration we are talking slow, but over a larger distance it becomes significantly more economic in terms of efficiency. You can travel large distances with greater overall speed compared to traditional means because it will just keep on accelerating.

--
Electronic Music Made Using Linux http://soundcloud.com/polyp

It ain't warp speed, and it ain't new either. by Lew+Pitcher · 2004-11-15 13:16 · Score: 2, Insightful

"It ain't warp speed, but it's exciting new technology at work!"

Ion propulsion isn't "new" technology at all. It's been around for fourty years or more, in one form or another. The only "new" thing about this ion propulsion is that it is being used as the motive power for a spacecraft.

See this article from the August 1964 edition of "Popular Mechanics".

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"values of beta will give rise to dom!"

This is what by Anonymous Coward · 2004-11-15 13:24 · Score: 2, Interesting

NASA should be working on developing - advanced propulsion technologies - instead of wasting its money on the shuttle and the ISS.

Unfortunately, pork politics and a generally uinformed space enthusiast community keep supporting these wasteful programs, even though almost all scientists and engineers admit both the shuttle and ISS are doing little if anything in helping us further space exploration.

Re:ideal? by WindBourne · 2004-11-15 13:51 · Score: 2, Informative

This was not about speed. It was about low costs and testing of durability. The US did the testing with Deep Space one. ESA has elected to do a moon mission.

The engine has ran quite a while and has proven that it is well made. I suspect that with the next generations of satillites (micro-sats), this will be the norm for propulsion.

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I prefer the "u" in honour as it seems to be missing these days.

Who needs sun? by zippthorne · 2004-11-15 13:57 · Score: 3, Informative

well yeah.. or RTG's (Radioisotope Thermoelectric Generators) I'm sure the power-plant will well outlast the propellant supply

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Can you be Even More Awesome?!

Technical project info by d2ksla · 2004-11-15 14:18 · Score: 3, Informative

The project home page can be found here: http://www.ssc.se/ssd/smart1.html

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Freevo - Linux Multimedia Jukebox

Ion propulsion for cars! by cpghost · 2004-11-15 14:22 · Score: 3, Funny

Imagine ion propulsion in our cars! Just gimme some months to reach those 55 mph...

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cpghost at Cordula's Web.

Re:Ion propulsion for cars! by antispam_ben · 2004-11-15 15:08 · Score: 2, Funny

Imagine ion propulsion in our cars! Just gimme some months to reach those 55 mph... I had a 1973 VW Beetle that drove like that.

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Tag lost or not installed.

Wikipedia link to propulsion system by Anonymous Coward · 2004-11-15 14:55 · Score: 2, Informative

SMART-1 uses Hall effect thrusters, somewhat different from the ion thrusters that the U.S. usually uses.

Re:Extinction events by kinzillah · 2004-11-15 15:31 · Score: 2, Informative

No. statistically speaking the odds are the same as they always were. Just because you flipped heads, does not make tails more likely to come up next.

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Douglas P. Price

Re:ideal? by uberdave · 2004-11-15 15:55 · Score: 2, Informative

However, this is the first time an ion engine has been used to leave orbit and re-enter orbit.

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"I'm not impatient. I just hate waiting." - My Dad

Re:One small... by Dr.+Spork · 2004-11-15 18:37 · Score: 2, Informative

Look, strictly speaking, the first man, woman, dog, satellite, etc. in space were all European.

Haven't been there. Done that. by Gorimek · 2004-11-15 18:55 · Score: 2, Interesting

You can get that on Earth already. Where I grew up, just down the street from the North Pole, we had 3 months of daylight during summer. And plenty of water ice, if that's important to you.

It's actually the one thing I miss the most. Once you've experienced life without any darkness, you realize how much the night cripples your life, and it's a hard thing to lose.

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