First Exotic Space Thruster Test Ends in Explosion

KentuckyFC writes "A NASA-funded test of an entirely new way to control orbiting satellites has ended with the prototype arcing dangerously and parts of the machine exploding. The new propulsion system is based on the Lorentz force: that a charged particle moving through a magnetic field experiences a force perpendicular to both its velocity and the field. So the plan is to ensure that a satellite passing though the Earth's magnetic field is electrically charged so as to generate a force that can be used to steer the spacecraft. The advantage of the idea is that it requires no propellant, which is a big deal since most satellites' lifespans are limited by the amount of fuel they can carry. But the first ground-based tests haven't gone entirely to plan."

I hope

[VeNoM0619]

parts of the machine exploding.

But the first ground-based tests haven't gone entirely to plan."

Good thing they told us that... I was beginning to lose faith in their work.

Explosions are an indicator of work

[iamlucky13]

The best projects usually have a development report buried somewhere in their history that contains the phrase, "...and then it exploded."

Percy Spencer (microwave oven): "...and then the egg exploded."
James Watt (steam engine): "...and then the boiler exploded."
Alfred Nobel (dynamite): "...and then the nitroglycerin-soaked soil exploded."
Vladmir Titov (Russian cosmonaut): "...and then the Soyuz rocket exploded."
Werner von Braun (NASA engineer): "...and then the Jupiter rocket exploded."
Yang Liwei (Chinese Taikonaut): "...and then the Long March rocket exploded."
Sony test engineer: "...and then the battery exploded."
J. Robert Openheimer: "...and then the Trinity device exploded"...oh wait, that was supposed to happen.

A more personal anecdote:
Someone in the shop at work needed a simple room-temperature dryer for a special project, so he got some large diameter PVC pipe that was handy, filled it with a desiccant, put the material in that needed drying, and screwed the cap on. Then he left it alone for a few hours.

Apparently some sort of gas-producing chemical reaction took place, probably helped by the sun shining through the open door, (...wait for it...) and then the drying chamber exploded, blasting the plastic lid through the ceiling 25 feet overhead and covering the work bay with the tiny pellets of desiccant.

Engineering is fun.

Re:

[jberryman]

Maybe "someone" (*COUGHyou) shouldn't be drying their special 'shrooms at work, eh?

Funny?

[dreamchaser]

Yes there is humor here, but this should be +5 Insightful. Almost EVERY engineering endeavor has involved catastrophic failures at one point or another. If people stopped trying after one such failure we'd be using flint hand axes and making fire with a bow drill still, if even that.

Re:

[iamlucky13]

Point taken and considered while I was typing it, but just between you and me, I was going for entertainment value.

Re:

[dreamchaser]

Honestly, if I had had mod points I would have been torn between funny and insightful, but funny doesn't add to karma and it was a good post that deserved a reward so I would choose insightful. Don't get me wrong, it also made me chuckle repeatedly. Thanks for that :-)

Re:

[burne]

Almost EVERY engineering endeavor has involved catastrophic failures at one point or another.

A pity you didn't say 'engineering succes', robbing me of a chance to point out that engineering failures involve failures as well. However, in a failure-in-the-making the failures tend to confirm existing knowledgde, while a wannabee-succes tends to reveal new knowledge. "I told you it wasn't strong enough" versus "that is not supposed to happen".

Re:

[master_p]

Indeed. Look at Microsoft Windows, for example. One catastrophic failure after the other, yet the boys at Redmond don't give up. Now that's science!!!

Re:Explosions are an indicator of work

[iamlucky13]

Since I basically just put words into people's mouths for a laugh, I figured I'd google up some actual quotes by these people related to their work.

• MIT coworker on Percy Spencer: "Like Edison, he will cut and fit and try and throwaway and try again."
• James Watt on one of his designs: "It is very defective."
• Alfred Nobel: "If I have a thousand ideas and only one turns out to be good, I am satisfied."
• Vladimir Titov after his Soyuz rocket exploded beneath him: "We were swearing."
• Werner von Braun (memory from childhood): "Selecting half a dozen of the biggest skyrockets I could find, I strapped them to the wagon. It performed beyond my wildest dreams. The wagon careened crazily about, trailing a tail of fire like a comet. When the rockets burned out, ending their sparkling performance with a magnificent thunderclap, the wagon rolled majestically to a halt. The police who arrived late for the beginning of my experiment, but in time for the grand finale, were unappreciative."
• Yang Liwei: "I did not see the Great Wall from space."
• Yet-Ming Chiang (MIT chemist): "The unstable materials release oxygen, oxidizing other materials in the battery, which in turn produces more heat. The cycle continues in a process called "thermal runaway," which in some cases can lead to a violent explosion."
• J. Robert Oppenheimer: "It worked."

Re:

[Dun Malg]

James Watt on one of his designs: "It is very defective."

No, that was James Watt describing the hasty description of potential steam powered carriage applications for his steam engine patent, included only to keep others out of the steam engine business in any capacity.

Clearly you noticed that the original Watt "quote" was in sharp contrast to reality when you searched and found nothing, but then you didn't even fess up! No, you just took one of his quotes out of context. Quit putting false words in Watt's mouth!

-Vengeful Steam Nerd!

Re:

[Vexar]

Tell your co-worker if he's going to dry something that used an adhesive with an alcohol or benzene base (or did he spray it down with Aqua Net?) to get a brushless fan next time. Darn thing creates a lot of EM interference... and internal sparks every once in a while. The desiccant played no part in the reaction. Still, if you have got a picture of the hole, I'd say it is worth sharing.

Re:

[Linker3000]

Microsoft "...and then Ballmer exploded and threw a chair"

ObGalaxyQuest

[kvezach]

Jason Nesmith: Did I just hear that the animal turned inside out, and then it EXPLODED?

Re:

[Instine]

True. But when things realy go bang, the injury, death and destruction is very real. Its all well and good saying we'd never progress without it, but tell that to the families of the workers smeared on walls. Someone at my school (many moons ago) decided he'd experiment with some Hexamethyltriperoxidediomene in the lav (frightening easy to make). We heard a big bang and then the kid in question running down the hall flinging bits of finger and hand here and there as he ran.

He lost large parts of all his

Re:

[radu5er]

Ah yes. These comments conjure up fond memories of when, as a curious child I began mixing various chemicals from my chemistry set...along with some additional ingredients from under the kitchen sink in a tightly sealed container. When the container began to bulge and heat up it was at this precise moment I suddenly realised the inherent danger of uncontrolled chemical experimentation. My Mother still recalls my excitement as I ran up the stairs shouting, "It's gonna blow!"

Heh

[Paranatural]

From TFA: And as long as nobody gets hurt, a decent explosion livens up any experiment.

I'm pretty certain this is how Mythbusters got started.

Also from TFA: Obviously, a proplusion system that explodes while it is in operation needs some more work.

I dunno, kinda sounds like how rockets work.

Re:Heh

[Arimus]

And not to mention the ill fated plan to detonate nuclear bombs behind a space craft as a method of propulsion...

(Orion programme if my memory isn't failing)

(On that point when will which ever god or other deity is responsible for our design fix the bloody faulty memory unit and start using error correcting cells?)

Re:Heh

[geekoid]

It's a valid method...just not inside the atmosphere.

Re:

[Arimus]

I dunno know - would cure the over population problem.

Might even stop global warming if it pushed the earth a bit farther out ;)

Re:

[zippthorne]

Sadly, it's not nearly as useful *outside* an atmosphere, as it's principle benefit is its high thrust. Electric propulsion can achieve much higher specific impulse if you don't have to worry about launch phase.

Re:

[burne]

Project Orion showed several designs with speeds up to 0.1c for 'conventional' thermonuclear propulsion, up to 0.5-0.8c for a theoretical matter/antimatter-design.

To achieve similar thrust and specific impulse with an electrical drive would need a propulsion-subsystem the size of Switzerland. (And yes, CERN could be considered to be a small-scale prototype).

Re:

[ironfrost]

?Maybe the same can be said for prototype in TFA. arcing should be less common in space.

The test took place in a vacuum chamber, so it shouldn't be any more likely to arc there than in space.

Re:Heh

[vux984]

(On that point when will which ever god or other deity is responsible for our design fix the bloody faulty memory unit and start using error correcting cells?)

Perhaps its a survival mechanism that keeps you from going insane and killing yourself before you reach age 10. The ability to forget might be the only thing keeping us sane.

Or maybe its a performance optimization - keeping the dataset smaller makes retrieval faster.

Or part of a disaster recovery system, enabling you not to be permanently traumatised after seeing the goatse guy. ;)

Re:

[kesuki]

Eidetic memory aside, there are countless things i can remember that i truly wish i could forget, and yet there are countless things i forget that i was trying really hard not to forget.

I mean, do i forever have to remember the time i nearly tripped and fell down a stairway and got a stick shoved through the roof of my mouth that i was holding in my mouth (was a toy magic wand) as i went downstairs to play with the magic wand? Why do i recall the time i was playing with my sister, hit the back of my head ag

Re:

[Vexar]

Oh come on, you honestly think you'd forget a cataclysm like that? I don't care how hard you rammed that stick into your soft palate, or hit your head on the staircase, You just don't forget tragic accidents. They build character. You know, there's this one scar I've got on my knee...

See what I mean? Listen, life is boot camp for eternity as far as I'm concerned. Live through it faithfully, and well, at least you've got some good stories to swap in heaven! I'm sure these NASA scientists are going to

Re:

[triffid_98]

Yes, it's called CH3CH2OH(Alcohol)

The ability to forget might be the only thing keeping us sane. Or maybe its a performance optimization - keeping the dataset smaller makes retrieval faster. Or part of a disaster recovery system, enabling you not to be permanently traumatised after seeing the goatse guy

Re:

[kesuki]

yes it was the Orion program, and as a matter of fact, it's the last best hope we in humanity have against a meteor or comet big enough to shatter a tectonic plate with it's impact (or to kick enough dust up to kill any animal not wearing air filters/ block out the sun for years or however long it takes for the dust to settle)

although, by the end of the Orion program, the idea was to build it in space (like a space station) and only detonate the bombs to get us all the way out to the large comet or asteroid

Re:

[smaddox]

I can just imagine sending an asteroid into Jupiter only for it to come out the other side and smack right into us.

It is a gas giant after all.

Re:

[pyrrhonist]

Is a comet [wikipedia.org] okay?

Re:

[kesuki]

I can just imagine sending an asteroid into Jupiter only for it to come out the other side and smack right into us.

It is a gas giant after all.

"Jupiter is thought to consist of a dense core with a mixture of elements, a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen.[23] Beyond this basic outline, there is still considerable uncertainty"

I think the liquid hydrogen will freeze and shatter any meteor we aim at jupiter... superheated in the atmosphere and then plunged into an ocean of metallic hydrogen...

besides there is believed to be at least and earth sized core, in some fict

Re:

[witherstaff]

Orion [wikipedia.org] was canned because of treaties against upper atmosphere testing. I first saw the idea in the novel Football [wikipedia.org]. It sounds like it could actually work, but doesn't sound environmentally, or human, friendly.

Re:

[rossdee]

"And not to mention the ill fated plan to detonate nuclear bombs behind a space craft as a method of propulsion. (Orion programme if my memory isn't failing)"

Yep. My question is, which idiot at NASA decided that their next series of spacecraft should be called "Orion" given the history of that name.

Project Orion

[Vexar]

Yes, that's the right project name, and US President George Bush naively named another project that of late. As far as your memory is failing, I'd like to point out that your brain still contains the memories, but you've managed the fuse the pathways (short the wires) with too much caffeine or asbestos or whatever fluff they use to make Teletubbies.

Ummm, I have to say you are wrong

[celtic_hackr]

This is the method of propulsion used by: the Sun the rest of the stars in the Universe, and is the primary propulsive of the Galaxies (from the net combined propulsion of the stars contained therein).

This of course is not taking into account the remaining velocity of the Universe's bodies from the Big Bang, but that is a residual velocity, as opposed to the current applied forces on those bodies.

Re:

[legirons]

And not to mention the ill fated plan to detonate nuclear bombs behind a space craft as a method of propulsion...

(Orion programme if my memory isn't failing)

see a talk about it at:

http://www.ted.com/index.php/talks/view/id/221 [ted.com]

It's Rocket Science

[mangu]

Also from TFA: Obviously, a proplusion system that explodes while it is in operation needs some more work.

I dunno, kinda sounds like how rockets work.

Sure, you got the basic points all right. Now, let's see some advanced stuff:

It should go like this [youtube.com]

NOT like this [youtube.com].

Re:It's Rocket Science

[TheRaven64]

You certainly get bonus points for irony using an Ariane 5 as an example of a rocket not blowing up...

Re:It's Rocket Science

[CCFreak2K]

From Wikipedia [wikipedia.org]:

As with many rockets, the initial flights of each new Ariane model have seen failures. However, overall, the Ariane 4 and 5 are the most reliable commercial rockets ever launched. As of January 2006, 169 Ariane flights have boosted 290 satellites, successfully placing 271 of them on orbit (223 main passengers and 48 auxiliary passengers) for a total mass of 575 000 kg successfully delivered on orbit. This success rate also makes Arianespace the foremost commercial launcher; in some years, more than two thirds of all commercial satellites have been launched with the company's vehicles.

A better example

[xmark]

would be this. [youtube.com] That's Spirit on its way to Mars aboard a Delta 2. Same rocket that was used to send Phoenix to Mars. Works for me.

Re:

[ricegf]

And definitely not like this [youtube.com].

Good for them

[LGV]

I'm actually glad to see NASA doing stuff that might not work. It seems that a lot of the space work thats been happening in the last decade or two has been stuff that we know we can do. There are still failures, but those tend to be metric vs imperial units issues, not because they're pushing forward in to new areas.

All new technology generates it's share of failures along the way. In the early days NASA blew up a lot of rockets in the process of learning to get them in to space. As long as we're using it on unmanned craft (or on the bench), a decent rate of failures is alright by me if they're learning something from them.

Re:Good for them

[jedidiah]

Goddard started out the same way...

Re:Good for them

[Applekid]

As long as we're using it on unmanned craft (or on the bench), a decent rate of failures is alright by me if they're learning something from them.

I'd have to say that mindset is the #1 reason why I like science so much. Even in failure there's so much to learn from it.

So I'm glad I got burned think of all the things we learned
For the people who are still alive

Re:

[barzok]

Even in failure there's so much to learn from it.

I wish I knew the source of this quote:

If you haven't failed, you haven't tried hard enough

Re:

[SlowMovingTarget]

Apparently, you've tried hard enough to find it.

Re:Good for them

[DerekLyons]

I'm actually glad to see NASA doing stuff that might not work. It seems that a lot of the space work thats been happening in the last decade or two has been stuff that we know we can do.

NASA has never stopped doing stuff that might not work - it's just that 99.99% percent of what does (successful or not) never makes Slashdot, let alone the mainstream media. Heck, even most of the stuff that's made the mainstream media hasn't really been 'stuff we know how to do'... Pathfinder, Spirit, Opportunity. Deep Space 1, Deep Impact, the Hubble repair missions, quite of the ISS assembly flights... I could go on, but those alone should suffice.
 
 

There are still failures, but those tend to be metric vs imperial units issues, not because they're pushing forward in to new areas.

Had NASA suffered a failure because of a units error - you'd have a point. I assume you mean Mars Climate Orbiter - which was lost because NASA failed to analyze it's trajectory during the cruise phase. Not because of a units error. The units error was a contributing cause, but one trivially corrected for had standard monitoring been in place (both in testing and in flight) - but it wasn't because of sharp budget restrictions.
 
Not to be offensive, but it seems your impression of what NASA is or isn't doing seems to arise from not paying attention.

Dirty

[Hatta]

I'd be concerned if I tested my exotic thruster and it didn't end in an explosion.

Re:

[Kryptonian Jor-El]

That's what she said

Re:Dirty

[p0tat03]

"She" has an exotic thruster? o_O

Protection

[DeadDecoy]

Ya, but you might want to use protection or you'll get burned.

Re:

[Anonymous Coward]

Well, that's why she's so exotic.

Doesn't seem like a significant setback.

[Pendersempai]

Here is the story, based on my admittedly non-expert reading: To use the (very exciting) Lorentz steering technology, the sattelite has to have an electric charge. The method they used to obtain the charge is to apply a voltage to a radioactive substance and then allow solar wind to carry away the positive charge, leaving the sattelite negatively charged. The problem seemed to be that this process caused sparks to arc across the sattelite, which in turn damaged electronics and dislodged soldering.

I'm not sure why this is a big deal. Couldn't they just use a different kind of solder, or at least insulate vulnerable electronics from the charge?

Re:Doesn't seem like a significant setback.

[v1]

That's what I was working on figuring out, from the wording of the article ("explosion") it made it sound like a big deal, like when a rocket launch goes bad. (see various youtube links in this thread)

But when I got to reading, they use the word "explosion" for solder. Solder is not big. It's not like a fuel tank went up - this is a little bit of electronics. That sounds like a smaller explosion than you get with your average match when you strike it.

That's like talking about buildings and saying there was a "collapse", and if you RTFA close enough you find what they're actually referring to is the water glass on the table in the lounge tipped over.

Honest perhaps, but definitely deceptive.

Re:Doesn't seem like a significant setback.

[smaddox]

It seems like arcing shouldn't be a huge problem in a vacuum. The charge would have to be isolated from electronics, because transistors wouldn't work very well if they had a high initial base charge.

However, isolating the transistors might be harder than it seems at face value because transistors must be used to control the mechanics of the satellite. If you tried to isolate the charge to the metallic chassis, it might be able to pass through control lines into the electronics. The resulting electric field could either keep transistors from depleting, or even worse, blow the dielectric.

It seems to me that an isolated piece of metal would have to be incorporated specifically to hold the charge. In order to isolate it you would need a dielectric with a very high breakdown voltage. However, even then the isolated charge would cause electric fields to appear across the rest of the satellite.

Hmm... That is not an easy problem at all.

Re:Doesn't seem like a significant setback.

[Agripa]

It seems like arcing shouldn't be a huge problem in a vacuum.

Arcing, or at least conduction, is a huge problem in a vacuum and can even be worse in a rarefied or ionized gas where the effective resistance will be much lower and negative resistance may manifest leading to sudden destructive discharge. Vacuum tubes contain a vacuum for proper operation and the only tricky requirement is a source of electron emission. The vacuum of space conveniently provides such a source in the ultraviolet radiation from the sun which will quite handily knock electrons off of the right materials and has no problem ionizing various gas atoms in the vicinity. A flame detector for safety applications can be made using a gas filled tube somewhat like a neon bulb and they work by watching for the characteristic ultaviolet from a flame which will ionize the gas.

However, isolating the transistors might be harder than it seems at face value because transistors must be used to control the mechanics of the satellite. If you tried to isolate the charge to the metallic chassis, it might be able to pass through control lines into the electronics. The resulting electric field could either keep transistors from depleting, or even worse, blow the dielectric.

I have never designed or worked with vacuum rated electronics (except for tubes and certain other devices with a self contained vacuum) but my guess is that a conformal coating is used to insulate all conductors from the vacuum. Conformal coatings are also used in high precision circuits to prevent surface leakage. Most of my work has been at the low end of the current and voltage spectrum (less then picoamps and nanovolts) but at the high end (kilovolts, amps, and kilowatts), I have occasionally found component failure mode to be "disappearance" with attendant explosive like effects.

Re:

[nahdude812]

<pedantry>I think since a positive charge is actually too few electrons, instead of solar wind carrying away the positive charge, it's depositing a negative charge (nothing is carried away).</pedantry>

It may be an issue that eventually enough charge is built up without any means of eliminating the excess that the voltage defeats conventional insulations.

Re:

[Vexar]

I thought Lorentz effect looked familiar. This is another one of those deep space only propulsions. It builds over time, like the plasma drives the Russians built. This is not a launch technology, and no matter how much NASA spends on "hey, here's something kinetic to fiddle with," they aren't focusing on the #1 problem: up. Not out.

Need more coffee

[truthsearch]

My brain initially processed the title as, "First Erotic Space Thruster Test Ends in Explosion". Needless to say I was very disappointed when I read the summary.

Re:

[Tomster]

I think you might be needing something other than coffee....

best to discover flaws early

[peter303]

You should watch videos of our first satellite attempts. I'm surprised we didnt have more fried astronauts.

Re:

[Scrameustache]

You should watch videos of our first satellite attempts. I'm surprised we didnt have more fried astronauts.

Delicious space-fried monkies.

Jazzing up the story a bit

[Goaway]

As much as we all like a good explosion, that summary seems highly misleading. From the abstract:

Microscopic arcing was observed at voltages as low as -300 V. This arcing caused solder to explode off of the object. Insulating the object allowed the charge to remain on the object longer, while in the plasma, and also eliminated the arcing. However, this insulation does not allow a net charge to reside on the surface of the spacecraft.

"Caused solder to explode off the object" hardly sounds like much of an explosion.

Re:Jazzing up the story a bit

[eln]

Oh sure, it doesn't sound that impressive until you realize the entire craft was covered in a 2-foot layer of solder.

Re:Jazzing up the story a bit

[ivan256]

When you play back the high-speed camera footage taken through a microscope on a 100" screen...

Oh, nevermind... Even then it's probably not a very impressive explosion.

It bothers me that the editors here simultaneously push the "we don't invest enough in space research" platform, and fall into the "journalistic" trap of sensationalizing NASA's failures to make their readers feel "smarter than those rocket scientist guys".

I have every expectation that the readers and comment writers on Slashdot have vastly differing opinions on the subject, but you'd think that the clearly biased editorial staff here could get their story straight.

Re:

[Slashdot Suxxors]

You must be new here.

Re:

[ivan256]

Why shouldn't we? Is that too much to expect? It seems perfectly reasonable to me to assume that a "news" organization can have a uniform policy of reasonable standards that they could hold their editors to.

Re:

[TheRaven64]

Hell, it's not even safe to treat the individual editors as coherent...

A real arc

[Skapare]

You don't know what a real arc is until it hits your house [youtube.com].

Re:

[Goaway]

What in the hell is going on in that video? It makes no sense whatsoever! Don't these people have circuit breakers?

Re:

[Skapare]

The circuit breaker feeding the distribution wires (that were damaged in some way by an unknown cause) apparently failed. These distribution wires are running somewhere between 7200 and 19800 volts relative to ground. What is happening is that as the wires burn down in various places, that voltage is crossing over to the 120 volt (relative to ground) wires going into the homes. The insulation on the home wiring would be rated for 600 volts, which means they could fail with as little as 2400 volts or less

Re:

[Goaway]

Well, I was mostly confused how, if the circuit breaker for the distribution lines really failed, they seemed to have no other way of cutting the power, at least not within the fairly long time this was going on.

Re:

[Skapare]

Is this one [youtube.com] easier to understand? It's a small construction crane, but big enough to contact a power line. Don't try this at home or anywhere.

Redefining your way to success!

[Chris Burke]

A NASA-funded test of an entirely new way to explode orbiting satellites has ended with promising success!

Well I certainly wouldn't

[iminplaya]

let a little thing like an explosion [nasa.gov] deter me.

Re:

[EricTheGreen]

From old age or the beer?

Another variant also had problems.

[Ungrounded Lightning]

Another variant of this is to have two weights connected by a wire tether and tide-locked to the primary, so the wire is oriented at roughly right angles to the orbit. Then you put a current in the wire by ejecting electrons on one end and collecting them at the other - making it into a motor that can accelerate or decelerate along the orbit. No reaction mass, run it off the solar collectors, etc. This also ran into issues with arcing.

They tried an experiment on this with the shuttle and a tether to a satellite they were launching, and found a problem: The motion along the orbit also causes it to act like a generator, powered by the orbital momentum. (This was known - and also has possible uses.) This produces a voltage gradient along the wire tether. So the tether has to be insulated to prevent arcing to the very low-pressure plasma that constitutes the high atmosphere and solar wind.

What they discovered was that minute flaws in the insulation caused localized arcs to the surrounding plasma. These were powered by the orbital motion relative to the earth's field and were very intense. They quickly melted through the thin tether.

So such a motor is not an impossibility. But it will require some heavy engineering work to get around this problem.

(It also says that large-scale tethered orbital structures have an additional problem to be solved: Keeping the tethers intact despite kilovolts of induced voltage along the tether and the resulting arcing.)

It's easy to think of space as filled with a hard vacuum. Unfortunately it's actually filled with very low pressure conductive plasma and near the Earth that's dense enough to be a major engineering issue.

Re:Another variant also had problems.

[Jesus_666]

So the lesson is "moving something by ionizing part of it is pretty hard to do in a conductive medium". Another lesson people tend to forget is "space research is all about blowing up things until you get it right". A new propulsion technology not working as expected during the first few trials is not quite counterintuitive.

Re:

[argent]

The motion along the orbit also causes it to act like a generator, powered by the orbital momentum. (This was known - and also has possible uses.)

Don't forget the ObReference: Tank Farm Dynamo [davidbrin.com].

Re:

[Agripa]

What they discovered was that minute flaws in the insulation caused localized arcs to the surrounding plasma. These were powered by the orbital motion relative to the earth's field and were very intense. They quickly melted through the thin tether.

That is interesting. Capacitors occasionally suffer from a similar problem where if the dielectric is not uniform, like it has a bubble or discontinuity, the extreme electric field change at the discontinuity where the dielectric constant changes will cause local

Re:

[Ungrounded Lightning]

"large-scale tethered orbital structures have an additional problem to be solved: Keeping the tethers intact despite kilovolts of induced voltage along the tether and the resulting arcing"

Would those same issues apply to a Space Elevator?

To a much smaller extent - at least for the skyhook/beanstalk variety. (Some of the tumbing ones might have issues.)

A skyhook is rotating with the Earth, which also means with the Earth's field lines. Or at least roughly:
- Any waving back-and-forth in the beanstal

dependant on earth's magnetic field?

[lobiusmoop]

Will this screw up when the earths field begins fluctuating when poles being going into reversal again?

Mind you, when this begins, I suspect the last thing we would be worried about if/when this comes would be the odd satellite crashing back to earth.

Re:

[Jeff DeMaagd]

I don't think the satellite is going to last that long, I don't expect to see a pole reversal in the next decade, I think it's more like hundreds of years away.

Re:

[dvase]

Will this screw up when the earths field begins fluctuating when poles being going into reversal again?

Seeing as the force generated is in a direction perpendicular to both the satellite's direction and the magnetic field lines, it really shouldn't have a major effect.

As long as the magnetic field stays at least somewhat parallel to the earth's surface, a lift force will be generated regardless of the field polarity.

Of course, if there is zero magnetic field that means no lift force, but that doesn't mean things immediately fall out of the sky, only the potential to drop a little in orbit until the fi

Left-hand rule

[Chmcginn]

The field can stay in the same place, but the field lines will have their vectors rotated 180 degrees. Left-hand rule [wikipedia.org] & all.

Of course, then all you need to do is charge the hull positively instead of negatively. (But it might not be possible to swap that without reconfiguring some hardware, which tends to be a problem in orbit.)

Not sure that was the best approach....

[CBob]

(pun intended) I suspect possible solder join problems here. The voltages they're working with are not exactly known for freely arcing unless it's a short. I did notice no mention of the current involved tho. If it was a high current application, it points to someone not insulating correctly. Over-ionized maybe? The excerpt didn't fill too many details in.

Refueling

[visible.frylock]

I was surprised to learn that satellites are not refueled more often. After a bit of googling, this pdf [dtic.mil] came up. From page 15:

Although the use of shuttle manned EVA evolutions to conduct on-orbit servicing has proven sucessful in LEO, shuttle operational limits preclude operations above 400nm. Satellites which operate in MEO or GEO with typical altitudes of as high as 22,000 nm are not accessible to shuttle flights at this time.

This was from 1996, but as I understand, basic shuttle capabilities haven't

Re:

[Jesus_666]

I think nm is nautical mile (1.852km).

If it were nanometers it would mean that LEO and MEO satellites were a serious threat to kneecaps. Geostationary satellites would be much easier to implement, though.

Not to be negative...

[Kingrames]

...but EVERY space thruster test should end in an explosion.

on principle.

Re:

[mozkill]

yeah, the engineers are probably just having some fun.

They blow things up all the time

[esampson]

I mean those guys are no rocket scientists.

What? Oh.....

They should have expected it.

[Ptraci]

This is how sputtering in a vacuum chamber is done, for manufacturing chips and coating surfaces. The company I work for builds power supplies for these vacuum chambers, and they generally require some arc handling circuitry. Here's [advanced-energy.com] a white paper on arcing.

If you have a negatively charged target in a plasma the target will attract positive ions which will knock bits off of the target if they arrive with sufficient velocity, otherwise they'll stick and neutralize the charge. In a sputtering chamber we want those bits knocked off. If we're sputtering something non-metallic we need to use RF to keep it charged.

The only failed test...

[Tracy Reed]

...is the one you don't learn anything from.

GO NASA!

Warp Core Breach

[CodeBuster]

One would think that NASA engineers had watched enough Star Trek to realize that if one does not reverse the polarity of the intermix injectors into the flow matrix before the plasma coolant leaks after a power surge then the warp core will breach...amateurs.

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[mozkill]

lol. that is really funny. thats a very well placed anecdote.

First Exotic Space Thruster Test Ends in Explosio

[__aahgmr7717]

Spacecraft charge has long been a problem with satellites. The OGO IV satellite (circa 1968) was frequently negative due to the fact that the electron temperature in the ionosphere is higher than the ion temperature. As such there is a net electron flow to the satellite until its charge repels the electrons for a balanced +/- flow. But this is not always the case since the solar panels on the craft have exposed electrical contacts. The charging panels can drive electrons away from the craft and give (ev

looping B field

[The Fun Guy]

From TFA:

The team tested the ability of various objects to hold a charge in a vacuum while being bombarded with plasma...Microscopic arcing was observed at voltages as low as -300 V. This arcing caused solder to explode off of the object.

In my experience, damn near everything shorts out in a plasma field if it will carry a charge.

If you want to deflect the plasma (and thereby use the resultant Lorenz force to thrust your spacecraft), you have to use microsecond pulses of surface charge, not continuous charge like you would get from a weak alpha-emitter. Continuous charge = intact plasma filament = charge lead right back to your surface. Break the filament and you still get the expansion of plasma, with the resultant force transferred to the spacecraft through the magnetic field.

"Magnetic forces do no work".

[goodmanj]

So my physics teacher taught me. Doesn't that mean that while this doohickey might allow you to tweak the orbit, you can't actually raise or lower the orbit's semimajor axis?

Doesn't sound very useful.

Heh...

[OMNIpotusCOM]

My first exotic thruster ended in an explosion as well, but I hit puberty a little early and didn't know what I was doing. She was fine with it... that's what she said anyway.

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[geekoid]

Wow, you had to stretch to come to your spurious conclusion about the myth that the government is full of incompetents and money wasters.

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[Fulcrum of Evil]

Too bad my inner child is Beavis.

Beavis is everyone's inner child.