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Spacecraft May Surf Magnetic Fields

kdawson posted more than 7 years ago | from the radioactive-space-stocking dept.

Space 98

Maggie McKee writes "Future spacecraft may surf the magnetic fields of Earth and other planets, taking previously unfeasible routes around the solar system, according to a proposal funded by NASA's Institute for Advanced Concepts. The electrically charged craft would not need rockets or propellant of any kind. To get charged up, the spacecraft could either fire a beam of charged particles into space or simply allow a radioactive isotope to emit charged particles. Because long, thin filaments have large surface areas for holding charge, the spacecraft might look like Einstein's head — with wiry filaments sticking out at all angles — or a weird space 'stocking.'"

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Last I Checked (1)

JensenDied (1009293) | more than 7 years ago | (#18343911)

Mercury has no magnetic field and the one around Mars is patchy and not nearly as strong as the on here on Earth.
Does that mean this would be better suited for terrestrial travel?

Re:Last I Checked (5, Informative)

headkase (533448) | more than 7 years ago | (#18343939)

The Sun's magnetospere is bigger than the orbit of Pluto if I remember correctly. And it doesn't have to be exclusive, you could use the magnetic "sock" for a stage of the journey and maybe propellents in another stage of the same voyage and then you short range teleport for the last 5000km ;). It's just another useful tool to employ from a mission planning perspective.

Re:Last I Checked (1)

headkase (533448) | more than 7 years ago | (#18343959)

magnetospere == magnetosphere.
One of these days I'll actually learn to spell or /. will integrate a checker and there will be much rejoicing.

Re:Last I Checked (0, Offtopic)

omeomi (675045) | more than 7 years ago | (#18344031)

One of these days I'll actually learn to spell or /. will integrate a checker and there will be much rejoicing.

Just use Firefox 2, it has a spell checker built in...

Re:Last I Checked (1)

JensenDied (1009293) | more than 7 years ago | (#18343961)

Ah okay, I was not aware of the effect of the Sun's magnetic field.

Re:Last I Checked (1, Troll)

cluckshot (658931) | more than 7 years ago | (#18345157)

The magnetic field of the sun is pretty strong but of course is highly variable. At one point in 2005 (about the time we got the strong hurricanes) there were several Coronal Mass Ejections that left the sun riding its field at extreme speeds. By the time one of them passed earth (29 minutes after ejection) the matter was going 15% of the speed of light. By the time the same CME passed Saturn, the matter was going 30% of the speed of light.

People get this right! The solar system is electrical. The whole universe is electrically driven. I know that there are a lot of people out there who just don't get it. That CME that went out so fast..., It had a substantial mass being a large fraction of the mass of the earth. In order to accelerate a mass like this and have it get faster going further and further out the charge on the grid that drives this is nearly beyond calculation. Just for the record all CME's accelerate going out though many are hardly as fast as the 2005 ones. This proves something a lot of people are unwilling to see. The sun is electrical and not NUCLEAR. The neutrinos are missing folks. If the sun was nuclear, the CME's would decelerate on exit from the sun. The Corona would be colder than the surface of the sun. The Corona is 2 million degrees and the surface of the sun is about 10,000 degrees.

This electrical reality is the source of the X-Ray emissions in the universe. It causes sun spots and CME's. It explains the forms we see in the universe. It represents the action of a field that is 10^39 times that of any G field that exists. It removes the need to explain things as "Dark Matter" and "Dark Energy" and it deletes those famous "Black Holes" and sadly for a lot of people who are just enchanted with the cute theories, it clobbers the "Big Bang." It also disrupts most of the accepted theory but here we see the electrical universe is real and it works. Now we are going to use if for propulsion. The wind is a blowing and it is going to blow away the old theories. Of course the course of science still advances one funeral at a time. I am sure some one of the old guys will declare me Troll rather than accept the obvious reality. Get a life if you disagree or post against me but forget the Troll stuff because I am not being troll to tell the truth.

Re:Last I Checked (1)

aeonturnip (1075549) | more than 7 years ago | (#18345243)

"I am sure some one of the old guys will declare me Troll rather than accept the obvious reality." Well, I'm not that old a guy, but statements like "obvious reality" do need to be backed up with some hard proof and proper theory, and last I heard, most folks were happy with the sun being powered by nuclear fusion rather than "electrically". By all means, let's see your theories and proof, and then we can all decide for ourselves.

Re:Last I Checked (1)

Gilmoure (18428) | more than 7 years ago | (#18348923)

Electrically straightened my teeth, rebuilt the transmission in my '72 Nova and made my wife's breasts larger. I love it!

Re:Last I Checked (1)

Control Group (105494) | more than 7 years ago | (#18346365)

It is not your theories which make you a troll, it's your lack of substantiation for same. Provide some research and evidence past simple assertions, and I'll pay attention. Until then, you're just another crackpot who's probably trying to get me to invest in his perpetual motion machine.

Re:Last I Checked (1)

Stanistani (808333) | more than 7 years ago | (#18347917)

Now, see what you've done. You've made Steven Hawking cry.

Re:Last I Checked (1)

eno2001 (527078) | more than 7 years ago | (#18350105)

Jesus K-Riste. This guy is NOT a troll. I was one of the guys deployed by Halliburton to rebuild the sun when it imploded and went black hole back in 1906. Of course, it wasn't called Halliburton then and that whole Tunguska thing was just a cover up. Fortunately, we already had a backup sun in place because we'd been anticipating this stuff since Leonardo (DaVinci) first noticed the magnetic fluctuations back in the day. The backup sun was one gigantic halogen lamp matrix and was being powered by a makeshift dynamo that used the kinetic energy of the two inner planets to drive it. That bought us about two months to rebuild the badly damaged sun.

The first thing we had to do was go find it. It was being quite naughty and buried itself in the Earth's core (it has kind of a bad attitude when it's not working right). But we were able to locate it easily thanks to more innovations by Leonardo that were remarkably prescient. Once we got it and told it that it had to keep working for at least another 2-3 billion years before it decided to play black hole games, we then had to rebuild the chair of the sun and the magnetic scaffolding around it. Those IBMers out there think they are "thinkers" they ain't seen nothin' when it comes to good old Halliburton genius. Most of us have several centuries of knowledge on your green horns when it comes to the technology that holds the universe itself together.

Anyway, we got the sun mounted on it's chair again, and then we got it hooked up to it's symbiont energy cells. They generate energy so the sun creates a magnetic field which the cells then use to create energy. Yeah, yeah... I know it's basically a perpetual motion machine even though they're not supposed to exist. And for all intents and purposes although it does appear to be perpetual motion, it's not really. It's just VERY VERY efficient so the time for spin down is on the order of a few million years and we give it a push ever few millennia or so. So yes, the sun is indeed electrical. Tesla wasn't crazy, but he made the wrong stock investments and got shafted. Sadly that's business and if you're not on the right side you end up dead and penisless.

For those mods who are going crazy with the troll button, stop it. Otherwise I'm going to have to talk to my buddies up in suite 23 and you'll learn the TRUE meaning of moderation in your daily life. You have been warned.

Re:Last I Checked (2, Funny)

WingedEarth (958581) | more than 7 years ago | (#18345731)

Don't you mean, "The Non-Planet Formerly Known As Pluto"?

Re:Last I Checked (1)

ultranova (717540) | more than 7 years ago | (#18349861)

Don't you mean, "The Non-Planet Formerly Known As Pluto"?

Even if Pluto was downgraded from "planet" into "big rock", wouldn't it still be called Pluto ? It is Pluto's status that is in question, not name.

Re:Last I Checked (0)

Anonymous Coward | more than 7 years ago | (#18343953)

Since you brought it up, when was the last time you checked?

Last time I checked, which was a few minutes ago, it did:

http://www.mercurytoday.com/news/viewpr.html?pid=2 1587 [mercurytoday.com]

Re:Last I Checked (1)

JensenDied (1009293) | more than 7 years ago | (#18343971)

Computer models based on the dynamo theory reproduce the properties of Earth's magnetic field well, but the weakness of Mercury's field is a puzzle. Theory predicts that it should have 30% of Earth's strength, but only 1% has been observed.
Actually it was today during this Astronomy course I'm in and that was part of the lecture.
Nice to see where this educational material is incorrect, but the field is still extremely weak.

Re:Last I Checked (1)

Yvanhoe (564877) | more than 7 years ago | (#18344021)

Mybe would it be useful to get a boost while still in earth's vicinity or maybe it would be really useful for satellite that would not have to embark a limited quantity of fuel anymore.

Re:Last I Checked (1)

Mr2cents (323101) | more than 7 years ago | (#18345023)

I think navigating such a thing could prove to be very difficult.. If they want to change the capacitance, then they'll have to roll it up or something like that.. adding extra weight. I wish them good luck, but I'm a bit sceptical.

Sidenote: did they use an image of MRO with an extra 'sock' attached to it in the article? It really looks like MRO.

Re:Last I Checked (1)

DestroyAllZombies (896198) | more than 7 years ago | (#18350999)

It's definitely MRO, you can identify HiRISE sticking out the side.

Re:Last I Checked (0)

Anonymous Coward | more than 7 years ago | (#18344213)

Yes, its best suited for hover boards!

Damn it, I want one!!

Re:Last I Checked (1)

Bromskloss (750445) | more than 7 years ago | (#18344561)

Mercury has no magnetic field

Wikipedia [wikipedia.org] : Despite its slow rotation, Mercury has a relatively strong magnetic field, with a magnetic field strength 1% as strong as the Earth's.

Perhaps you mean it's not strong enough?

Re:Last I Checked (1)

Gilmoure (18428) | more than 7 years ago | (#18348963)

Mercury uses Deodorant of the Gods! Not just for Venus anymore.

Mercury's Magnetic Field (1)

Pchelka (805036) | more than 7 years ago | (#18351211)

Mercury has no magnetic field and the one around Mars is patchy and not nearly as strong as the on here on Earth. Does that mean this would be better suited for terrestrial travel?

You are correct that Mars has a very weak, patchy magnetic field. However, Mercury does have a rather strong magnetic field. Mercury even has a magnetosphere, even though it does not have an atmosphere. In fact, the MESSENGER spacecraft [jhuapl.edu] is currently on its way to Mercury to study the planet's magnetosphere. Venus [ucla.edu] , on the other hand, does not have a magnetic field.

not spacecraft. (3, Interesting)

YenTheFirst (1056960) | more than 7 years ago | (#18343935)

with the power involved here, it wouldn't be propelling any manned missions.

After reaching orbit, his present design would be off to a slow start, taking about a year to escape the Earth's gravity.
this seems like it would only be useful for satellites and probes and such.

Re:not spacecraft. (1)

Nyeerrmm (940927) | more than 7 years ago | (#18344195)

It's still a spacecraft, just not a manned spacecraft. And I don't know much about the technology, but if its anything like acceleration from ion drives, it may take a while to get going but it could still be fastest method in the long term for a long trip (longer than one to Mars I would guess.)

Re:not spacecraft. (1)

simm1701 (835424) | more than 7 years ago | (#18344535)

Um why not a manned space craft?

Any manned mission would need a huge amount of support equipment and probably a very large ship. Putting enough fuel in orbit to speed it up would be expensive. Speeding it up this way and then shuttling the human personel in using a much smaller ship (eg a shuttle) that could catch up to that speed ansd rendevous without needing anywhere near as much fuel would certainly be possible

If its just going in a circle while it speeds up it doesn't mean its out of range for us.

Re:not spacecraft. (1)

SatanicPuppy (611928) | more than 7 years ago | (#18345877)

RTFA. It says in the article, that the acceleration from this thing would be on the slow and steady side, and that it might take a spacecraft propelled by this technology "as much as a year" to break out of Earth's magnetic well.

We'd start having huge astronaut endurance issues before they got anywhere cool.

Re:not spacecraft. (1)

CmdrGravy (645153) | more than 7 years ago | (#18346087)

The obvious solution to this is to not climb aboard the craft until it's reached a decent speed. Launch it a decade or so before you wish to fly anywhere and have it do trips around the sun and back building up it's speed. When it's going fast enough build a very fast short range rocket to match it's speed and allow the astronauts to board.

Re:not spacecraft. (1)

jojoba_oil (1071932) | more than 7 years ago | (#18346567)

Then what would be the point? If you could match the speed once it got past the snail-crawl, why wouldn't you just use that technology instead?

So assuming this craft would use the same technique for deceleration, once this thing got to its destination would it have to boomerang around the local star a few times before it could slow to a speed more conducive to deboarding? Or can we just expect that by the time this thing would even have accelerated enough to be useful in the first place, all human passengers would have died of boredom/life-support-system exhaustion?

Re:not spacecraft. (1)

CmdrGravy (645153) | more than 7 years ago | (#18347339)

If you already have most of the spaceship in space flying along and the only thing you need to add to it are some pilots you will be able to build a rocket capable of getting the rocket and the few passengers to the same speed as your mothership. The rocket would then stop accelerating and carry on at the same speed whilst the mothership would continue to accelerate.

You wouldn't be able to attach the rockets to the mothership and accelerate it to the same speed it is able to reach on it's own after 10 years or so because you would need a huge amount of fuel and once it had ran out you would stop accelerating.

Re:not spacecraft. (1)

simm1701 (835424) | more than 7 years ago | (#18346479)

RTFP - I was suggesting letting it get up to speed and THEN putting people on board

I also rather like the other comment here of speeding it up even further by doing solar orbits before you actually put people on board - that might start to challenge how quickly we can accellerate a small ship to rendevous... but it would be very interesting!!

Re:not spacecraft. (1)

2short (466733) | more than 7 years ago | (#18355023)


If you can catch up to it, why climb on board? You're going to have the same issues decelerating at the other end too. Even as an unmanned cargo drone, sent ahead with supplies it doesn't work. The reason it's slow is itdoesn't push very hard; give it lots of mass to push and it's not slow but glacial.

This sounds great for a lightweight unmanned probe that just keeps steadily accelerating forever. Other than that I can't see it.

Einstein's head? (0)

regularstranger (1074000) | more than 7 years ago | (#18343949)

We probably could have done without the last sentence in the summary, but thanks anyway.

oh great (1, Funny)

User 956 (568564) | more than 7 years ago | (#18343965)

Future spacecraft may surf the magnetic fields of Earth and other planets, taking previously unfeasible routes around the solar system

I'm not sure this "surfing the galaxy" technology is a good idea. It'll just be used to lead Galactus here to consume our planet.

Re:oh great (1)

ControversialMatt (1070718) | more than 7 years ago | (#18348371)

He's already on his way if the new Fantastic 4 movie is true.

Cool! (1)

Max Littlemore (1001285) | more than 7 years ago | (#18344019)

Gotta get me some freaky space stockings

So... (0)

Anonymous Coward | more than 7 years ago | (#18344053)

what I wanna know is, where's my damn FLYING CAR?!

Re:So... (0)

Anonymous Coward | more than 7 years ago | (#18344443)

Ballmer can throw only chairs, wait a bit.

Re:So... (1)

Gilmoure (18428) | more than 7 years ago | (#18349049)

MS is going to develop cloned Mega-Ballmers and there will be one located at every house and parking lot, just waiting to throw a car when someone chants Developers, developers, developers?

Umm... capacitance of the ball made of filaments? (5, Insightful)

Alex Belits (437) | more than 7 years ago | (#18344069)

But the amount of charge held by a sphere at a given voltage, a quantity known as its capacitance, is not very large. Long, thin filaments, on the other hand, have a lot of charge-holding surface area, so one possible design involves many filaments attached to the spacecraft. The setup would have a rather comical look - because of the static charge, the filaments would stick out in all directions, like newly brushed dry hair.


Where did those people study Physics? It doesn't work that way.

The only surface area that matters is an equipotential surface, so in the case of "filaments sticking in all directions" it will be a roughly spherical surface formed by the ends of filaments. Within this sphere there is almost no electric field -- filaments can be seen as a kind of lightning rods, except there is no lightning because they are in vacuum. So at best they will have a larger sphere, at worst a cigar or other shape with less surface area. If one has to build a large but light sphere, he can make it out of the wire mesh -- in vacuum it won't discharge like it would in the air, where those spheres have to be smooth. Filaments or spikes can be useful for acceleration of charged particles.

As for usefulness of the whole thing, I guess, you can use this for steering the spaceship, however the analogy to surfing is very poor. Surfboards can accelerate by absorbing the energy of waves moving from deep to shallow water. This thing flies through a stable magnetic field, steering by changing its electric charge. A better analogy would be a sailboat changing tacks, with gravity acting as a wind and magnetic field as water resistance.

Re:Umm... capacitance of the ball made of filament (1)

Ceriel Nosforit (682174) | more than 7 years ago | (#18344131)

...in vacuum it won't discharge like it would in the air, where those spheres have to be smooth.


It would discharge in vacuum aswell, but the body is capable of holding on to a lot more charge without doing so. Lots more.

The geometry of the body still matters too, since equal charges push each other away. A corner would have a lot more electrons pushed into it, eventually causing them to "squirt" off the sharp edge or corner. This is called "corona discharge", and is what makes Tesla coils look pretty.

Re:Umm... capacitance of the ball made of filament (3, Informative)

Alex Belits (437) | more than 7 years ago | (#18344405)

Corona in a gas is easy to produce because gas can be ionized by strong electric field along the spike or fiber, giving you a lot of charged particles to carry your discharge current. In vacuum you have nothing but those electrons that are already in metal -- you can emit them if you are negatively charged, and can't emit anything if you are positively charged (think of it as a giant diode tube). Even if you emit electrons, you have to move very fast so magnetic field will divert them away from you, and once you are sufficiently positively charged, emission will stop.

Most likely at best this will produce a cloud of electrons following a positively charged spaceship, so forces that magnetic field applies to both will almost completely compensate each other. With radioactive source of charged particles (positively or negatively charged), or electron cannon you can produce more charge on the spacecraft, and probably it can be combined with ion engine that produces charged particles anyway.

Re:Umm... capacitance of the ball made of filament (1)

Ceriel Nosforit (682174) | more than 7 years ago | (#18344465)

Oh, right! I didn't think about a positive charge. - Though that would limit the greatest possible charge to the number of electrons you can do without. I'm not sure how that works out into real numbers...

Re:Umm... capacitance of the ball made of filament (2, Insightful)

Alex Belits (437) | more than 7 years ago | (#18344663)

It will be the same as in vacuum tubes and CRTs -- spikes themselves won't do much, but you can heat up the cathode, and create some electric field with anode -- electrons will be emitted, some of them will be captured by anode, the rest will escape the device, leaving it positively charged. As long as anode is positive relative to cathode, electron cannon will work. You can lose electrons until the point when you are so positively charged that all electrons that left the cannon have less energy that it is necessary to leave the spaceship.

Or you can make a source of positively or negatively charged ions -- they can be accelerated in a similar way. Again, this probably can be much easier achieved by messing with an ion engine, under/over compensating the positively charged ions that leave the engine.

Re:Umm... capacitance of the ball made of filament (2, Insightful)

Ceriel Nosforit (682174) | more than 7 years ago | (#18344867)

With a radioactive source emitting alpha and beta radiation it might be possible to use two ion drives; one ejecting the positively charged alpha particles and the other ejecting the negatively charged beta particles. That way you won't build up a total charge in the craft. Plus, there won't be any charged cloud tracing the craft since the sum total charge of the ejecta is zero.

Though apparently, the NASA people WANT to build up a charge... Meh.

Re:Umm... capacitance of the ball made of filament (1)

pclminion (145572) | more than 7 years ago | (#18348893)

With a radioactive source emitting alpha and beta radiation it might be possible to use two ion drives; one ejecting the positively charged alpha particles and the other ejecting the negatively charged beta particles.

For that to work, the two materials would have to emit charge at exactly the same rate (more accurate, the beta rate would have to be twice the alpha rate, because alpha has twice the charge of beta). You could place just the right amount of two materials to INITIALLY have the same rate, but because no two materials (unless they are identical) have the same half-life, the rates would eventually not be matched and a charge would start building up.

Unless you had a way to actively manage the particles and control how many of them actually left the spacecraft (which I think would be difficult) I don't see how it could work, except momentarily.

Re:Umm... capacitance of the ball made of filament (1)

Ceriel Nosforit (682174) | more than 7 years ago | (#18349733)

The breakdown doesn't have to occur simultaneously. When the alpha particle radiates, two electrons will be freed. A single electric field could direct the differently charged particles in opposite directions, then down to the awaiting ion engines.

Re:Umm... capacitance of the ball made of filament (0)

Anonymous Coward | more than 7 years ago | (#18344223)

The only surface area that matters is an equipotential surface, so in the case of "filaments sticking in all directions" it will be a roughly spherical surface formed by the ends of filaments.

I don't believe this would be the case. To use Gauss's law to calculate the charge at a surface, you have to have an actual closed physical surface along the equipotential surface. Consider a charged metal ball with a metal spike on the end of it. The charges would not congregate at the tip of the spike, but would distribute non-uniformly across the entire surface of the conducting object. Now consider a ball with two spikes. Now four, etc.

The charges would therefore distribute along the entire physical surface of the object, including the surfaces along the length of the filaments.

Observe a graphical representation [nexusresearchgroup.com]

Re:Umm... capacitance of the ball made of filament (1)

Alex Belits (437) | more than 7 years ago | (#18344329)

Equipotential surface does not need a conductor along it. Drill a hole in a metal sphere on a Van de Graaf generator, and it will make no difference except for immediate edges, the potential in the center of the hole will be approximately the same as it was when there was metal in it.

Re:Umm... capacitance of the ball made of filament (1)

Alex Belits (437) | more than 7 years ago | (#18344425)

...and to make it even more clear -- no, charges do not get evenly distributed along the surface. They repel each other to the end of the filaments, and ends of the filaments repel from each other, forming a sphere.

Re:Umm... capacitance of the ball made of filament (1)

indifferent children (842621) | more than 7 years ago | (#18345439)

Where did those people study Physics? It doesn't work that way.

Carl Sagan said that the ship would look like a dandelion, so it's going to look like a dandelion, physics be damned!

Re:Umm... capacitance of the ball made of filament (1)

Code Master (164951) | more than 7 years ago | (#18345517)

Unless the material is non-conductive and the charge is fixed into the material...

Re:Umm... capacitance of the ball made of filament (1)

Alex Belits (437) | more than 7 years ago | (#18345753)

If the charges can't distribute themselves to the lowest-energy configuration, it means that higher potential difference corresponds to the same charge, what means your capacitance is lower. Same happens when you pull the capacitor's conductors to put thicker dielectric between them -- charge is the same, energy is added therefore capacitance is lower.

Re:Umm... capacitance of the ball made of filament (1)

chrismgtis (1062106) | more than 7 years ago | (#18345689)

>>>A better analogy would be a sailboat changing tacks, with gravity acting as a wind and magnetic field as water resistance.

Sure, then when we have a gay space ship.

Spacecraft charging and attitude control (1)

Pchelka (805036) | more than 7 years ago | (#18352023)

Within this sphere there is almost no electric field -- filaments can be seen as a kind of lightning rods, except there is no lightning because they are in vacuum.

Space is not as empty as people think. The near-Earth space environment, and the space environments of any planet with a magnetosphere, are full of plasma. As a result, spacecraft charging and electrical discharges (think lightning) are a problem for spacecraft. This problem has been studied by a lot of people, including NASA's Electromagnetic Effects & Spacecraft Charging Working Group [nasa.gov] .

As for usefulness of the whole thing, I guess, you can use this for steering the spaceship, however the analogy to surfing is very poor.

I admit that I didn't really understand this article or how this spacecraft design is supposed to work. The people working on this have probably published something a bit more technical that would do a better job of explaining it. However, the idea of using magnetic fields in space to "steer" spacecraft is not new. Interactions between the Earth's magnetic field and magnetic torquer coils [magson.de] are already being used for attitude control and spin rate control on satellites.

trouble (0)

Anonymous Coward | more than 7 years ago | (#18344073)

Will they be able to identify Klingons?

Who else got this picture? (0)

Anonymous Coward | more than 7 years ago | (#18344075)

I couldn't help getting Zardoz flashbacks only the head looks like Einstein.

Re:Who else got this picture? (1)

Tablizer (95088) | more than 7 years ago | (#18350231)

I couldn't help getting Zardoz flashbacks only the head looks like Einstein.

I was thinking the same thing, and searched for "Zardoz" to here. As long as it doesn't barf guns out for crazed wrestlers, we might be okay this time. (That was an LSD-inspired movie if there ever was one.)
       

Fixed it for you (2, Informative)

TheTopher (879626) | more than 7 years ago | (#18344095)

Mason Peck of Cornell University in Ithaca, New York, US, has received a grant to study the idea, which is based on the fact that magnetic fields exert forces on electrically charged objects with a velocity that is not parallel with the field lines.

I'm guessing this system will work by having an orbit that travels over the magnetic poles, as the magnetic field lines are much closer there, and reversing the charge between poles so that it doesn't end up at the same altitude as it started. One problem, the further you get from Earth, the further apart the lines and therefore, less force. It seems as if it's going to take a very long time to get anything close to an escape velocity (if even possible). Who knows, it may even be more efficient to just shoot those charges out the back, aka ion drives.

Re:Fixed it for you (0)

Anonymous Coward | more than 7 years ago | (#18358251)

ok, my 12 year old son and i have been kicking this idea around for a little while and want to ask if anyone has thought of this idea not for a spaceship, but for a car type vehicle.. hover, or back to the future type? i'm thinking of a generated type of field e.i. magnetic,, to keep the "car" afloat. the problem we see would be to find a consistant "frequency" of earth's field to work from. increasing or decreasing intensity for altitude, and the changing field in front someone else suggested for direction , sort of the sailing idea. what do you think? because your comments seem pretty close to what we were thinking.

Atlas Attacks? (1)

Nesgar (590175) | more than 7 years ago | (#18344139)

That space-stocking looks suspiciously like Atlas' Crystal Castle from Astroboy. New Scientist hiring ex-manga artists perhaps...

Remember Force=Velocity x B (magnetic field) (4, Interesting)

viking80 (697716) | more than 7 years ago | (#18344355)

Anyone who remember physics 101 will recall the following:
A magnetic field will create a force normal to the velocity of a charged object. So
1. The force on any charge will be normal to the velocity, so it will move around in circles. This includes the charged spacecraft. (The field here is not homogeneous, but still, no gain in energy)
2. A current loop(i.e. a moving charge) can change the energy or be accelerated in a magnetic field.

(2) is and has been used since the first satellites were orbited to do orbital corrections, and are well understood and used. It can allow the life of the satellite to be expanded by many years.

Why would this craft not just use a long current carrying wire instead.

Re:Remember Force=Velocity x B (magnetic field) (1)

Jesrad (716567) | more than 7 years ago | (#18346655)

Why would this craft not just use a long current carrying wire instead.

Actually, this is exactly the principle of the magsail: magnetic solar sail. You deploy a long wire loop on every side of the spacecraft, circulate a current in it, and it catches the Earth's or Sun's magnetic field to propel the spacecraft.

A spacecraft using this method of propulsion could even launch in complete silence from either Pole, if it had a sufficiently large coil and current. An alternative to the wire is to use ionized gas instead: as the distance from the magnetic field increases, the conducting loop of ionised gas extends and compensates the loss of "strength" of the magnetic wind perfectly by catching even more of it, so it gives a constant thrust.

Re:Remember Force=Velocity x B (magnetic field) (1)

pbaer (833011) | more than 7 years ago | (#18353723)

"Why would this craft not just use a long current carrying wire instead?"

This is actually answered directly in TFA. The short anwser is that this has the potential to be much smaller.

Other methods of propellantless space travel have been suggested before, including solar sails and electrodynamic tethers. Like Peck's proposal, tethers are also designed to get a grip on planetary magnetic fields, but in a slightly different way, by sending an electrical current along a wire.

Tethers may prove hard to control, however; and both tethers and sails would have to be huge measuring at least 20 to 30 kilometres, says Peck. "We're proposing something much lighter and smaller." He thinks he can get similar performance with a stocking about 2 or 3 kilometres long, and because it could be made from lightweight carbon fibre, it would have a mass of only a few kilograms.

Re:Remember Force=Velocity x B (magnetic field) (1)

viking80 (697716) | more than 7 years ago | (#18354143)

My point was how can this work? I can suggest to use a 300m sombrero made of nanotubes, that would give better performance than the 3 km carbon tether.

But unless I gave a clue on why it would be better it would not be worth very much.

why wires don't work (0)

wizardforce (1005805) | more than 7 years ago | (#18344423)

Why would this craft not just use a long current carrying wire instead
because as you remember, high currents are required in a wire/tether to accelerate a craft if its going to be used for manned missions. when NASA attached a 13 km tether to the space shuttle, the induced current was about 9600 volts. the tether fried and detached from the shuttle. you are correct that for small craft, especially un-manned ones like probes- it is a great idea.

The force on any charge will be normal to the velocity
just for future notice "normal" refers in this case, to the property of magnetic fields applying a force perpendicular to the field lines. no force is ever encountered parallel to the field lines due to the magnetic field. The time it takes the craft to move out of orbit depends on the power supplied to the system, the mass of the system and the gravity well you wish to escape.

Re:why wires don't work (4, Insightful)

frostband (970712) | more than 7 years ago | (#18344529)

"induced current was about 9600 volts"

Why do I feel the need to point this out?

I know what he meant, but why did you make me reply? Damn you, EE degree, stop controlling my life!

Re:why wires don't work (1)

frostband (970712) | more than 7 years ago | (#18344537)

why did you make me reply? Damn you, EE degree, stop controlling my life!

So your life is Slashdot?

How sad...but common

Re:why wires don't work (1)

guruevi (827432) | more than 7 years ago | (#18345433)

induced current was about 9600 volts

That's probably why it didn't work then eh... somebody screwed up by using 2 different units in their calculations?

Re:why wires don't work (0)

Anonymous Coward | more than 7 years ago | (#18348789)

actually, the voltage on the TSS-!R tether was about 3.5 kV.
The tether failed because it had been sitting on a spool in a warehouse for several years, and the compression of the inner part of the wind resulted in insulation flow that caused a weak spot in the insulation. NASA failed to test the tether for integrity prior to launch.

Re:why wires don't work (1)

pclminion (145572) | more than 7 years ago | (#18348979)

the tether fried and detached from the shuttle.

There is only a finite amount of movable charge (electrons) inside the wire. The tether basically turned into an electric dipole. The current which flowed as the dipole formed was enough to cause heat damage. But had that damage not occurred, the current would eventually have stopped flowing, as the dipole reached its maximum magnitude.

Somebody else already pointed out the "9600 volts of current" thing. I won't go there.

no force is ever encountered parallel to the field lines due to the magnetic field.

Unless you happen to be a magnet.

29 comments, and no references to Eureka Seven (0, Offtopic)

Alex Belits (437) | more than 7 years ago | (#18344483)

WTF? Really, WTF?

Re:29 comments, and no references to Eureka Seven (1)

aldo.gs (985038) | more than 7 years ago | (#18347705)

Come on, not every geek/nerd likes anime. I know I do.

Unless by "Eureka Seven" you mean "Linux" or "Beowulf Cluster", or something like that.

Important!!! Don't let the Pastafarians know this! (1)

Tjp($)pjT (266360) | more than 7 years ago | (#18344567)

Because long, thin filaments have large surface areas for holding charge, the spacecraft might look like Einstein's head -- with wiry filaments sticking out at all angles -- or a weird space 'stocking.'

Oh no! The Pastafarians secret spaceship design has leaked out. Now all the acolytes of The Flying Spagetti Monster [venganza.org] will know the high inner circle secret that it is HE who travels by the spaceship and not that HE is the spaceship.

Let the people from DUBAI know of it... (1)

retrosteve (77918) | more than 7 years ago | (#18345305)

And they really WILL make a spaceship modeled on Einstein's head.

They have a little fetish for cute stuff like that.

http://guide.theemiratesnetwork.com/living/dubai/t he_palm_islands.php [theemiratesnetwork.com]

Re:Let the people from DUBAI know of it... (1)

hotdiggitydawg (881316) | more than 7 years ago | (#18345891)

And they really WILL make a spaceship modeled on Einstein's head.
That prompts the rather zen-like question... what would Einstein's head look like if it was approaching at the speed of light?

I don't know the answer, but I'm sure the resultimg impact would be most entertaining.

36 comments and... (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#18344755)

No reference to the Silver Surfer?

just be sure (1)

Bastard of Subhumani (827601) | more than 7 years ago | (#18344865)

Just be sure not to touch it when it lands - at least not without Earthing (or Marsing or Mercurying) it first!

Re:just be sure (1)

MichaelSmith (789609) | more than 7 years ago | (#18345263)

not without Earthing (or Marsing or Mercurying) it first!

Harry Harrison has suggested that humans in the distant future will wonder why we named our home world "Dirt". But anyway I can't imagine that in a future mars colony the three wire AC will come as Active (brown), Neutral (blue) and Mars (striped green/yellow). I think we will all just quietly ignore the inconsistency and call it Earth.

Re:just be sure (0)

Anonymous Coward | more than 7 years ago | (#18345925)

That's why the intelligent part of the world calls it "ground"

Re:just be sure (0)

Anonymous Coward | more than 7 years ago | (#18349629)

i believe it is usually refered to as ground, which is not the same conotation as earth, mars would have ground, composed of mars (not earth)

A few glitches in this idea: (3, Informative)

Ancient_Hacker (751168) | more than 7 years ago | (#18345059)

A few glitches in this idea:

  • Building up and keeping a substantial charge may be difficult-- the solar wind will tend to get in the way.
  • "Steering" is a bit misleading. Assuming you can only shoot out electrons, you're limited to one polarity of charge, so you can only turn in one direction, normal to the magnetic field.
  • Most planets have a bit of inclination, so you're going to be turning into an angle to the ecliptic-- not very useful if you want to aim at another planet.
  • A sudden solar flare is likely to really mess up the charge, leading to unexpected twists and turns.

Re:A few glitches in this idea: (1)

MichaelSmith (789609) | more than 7 years ago | (#18345307)

Most planets have a bit of inclination, so you're going to be turning into an angle to the ecliptic-- not very useful if you want to aim at another planet.

Niven and Pournelle made the point in The Mote in Gods Eye that if you build a laser boosted solar sail to travel to another star then you could use the galactic magnetic field to do a 180 degree turn, approach the target star from the opposite direction, and then use your laser boost to slow down.

In the story that wasn't used because the people running the laser were expected to be dead soon, but I think the point about this being good for very long, slow flights is relevant. Its not really something you would use in the solar system.

OTH if you were deep in the magnetic field of Jupiter it might be a good way to generate thrust. It might work at saturn as well. Magnetic fields have been used to stabilise satelites in low Earth orbit.

Kooky (1)

superdan2k (135614) | more than 7 years ago | (#18345071)

I'm guessing that all of those filaments are going to add a LOT of launch mass. Why not just make use of an M2P2 [slashdot.org] system [wikipedia.org] ?

Steering? (1)

Fyzzler (1058716) | more than 7 years ago | (#18346241)

I don't doubt that this will produce thrust. But I don't see how they will be able to direct the thrust in a specific controllable direction.

Re:Steering? (1)

superdan2k (135614) | more than 7 years ago | (#18360287)

I'd think that they'd be able to adjust the shape of the generated magnetosphere. It might not turn on a dime, but it should be steerable.

The Sun Goes Down and the World Goes Dancing (0)

Anonymous Coward | more than 7 years ago | (#18346459)

What does Stephin Merritt think of all this?

Kind of stupid. (0)

Anonymous Coward | more than 7 years ago | (#18346593)

I mean, come on. Why are we developing all these "space-sails"? I've read in the last couple months a few stories about different kinds of sails.

Why are we trying to make devices that ride solar wind, or magnetic fields, when we should be developing REAL space engines and such?

It's just plain tacky, inefficient and slow. Sure it's kind of fun, but why are we making devices that take SO long to get places? Humans only live so long...

Re:Kind of stupid. (1)

exp(pi*sqrt(163)) (613870) | more than 7 years ago | (#18349033)

Why are you posting on /. when you could be out saving lives? Could it be that not everyone has to work on the same thing all the time?

Here's one (0)

Anonymous Coward | more than 7 years ago | (#18346621)

Here's an illustration of the spacecraft running Linux! [berkeleybreathed.com] I can't get Netcraft to confirm it, though. All I get from them is "In Soviet Russia, spacecraft launches YOU!" But imagine a beowolf... sorry, never mind. I'll go take my meds and be quiet now.

Shennanegans (1)

Luxifer (725957) | more than 7 years ago | (#18346763)

first they say:

would not need rockets or propellant of any kind
and then immediately after, say:

fire a beam of charged particles into space
..how is this not a propellant?
"in this house we obey the laws of thermodynamics!"

Not a sock ... a towel! (1)

IwantToKeepAnon (411424) | more than 7 years ago | (#18346999)

Everybody knows that a hitchhiker's best friend (other than a babelfish) is a towel ... not a sock. :))

Comical Idea (1)

BigPaise (1037782) | more than 7 years ago | (#18347405)

'Tis the last of the old Dick Tracy comic strip technologies to be realized.

Better hurry (0)

Anonymous Coward | more than 7 years ago | (#18348837)

Lets just hope they get to test this before the poles swap or the earth's core solidifies.
This is eminent, I have seen it on TV yesterday.

electric solar wind sail (3, Informative)

jovius (974690) | more than 7 years ago | (#18349809)

There exists another interesting invention around about the same principles. This one however uses solar wind, not magnetic fields, is steerable and able to work itself against the solar wind by adjusting the polarity and charge of the individual wires. They are apparently doing practical research on this right now. A short english description can be found at http://www.electric-sailing.fi/index.html [electric-sailing.fi]

OUPSSS (1)

Chris whatever (980992) | more than 7 years ago | (#18352125)

a black hole

Gradisil (1)

JudgeSlash (823985) | more than 7 years ago | (#18355961)

Adam Roberts would be proud. This sounds like his latest novel, "Gradisil", where the spacecraft 'push' against Earth's magnetic field to lift up to orbit.
Awesome book. Read it! http://en.wikipedia.org/wiki/Gradisil [wikipedia.org]
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