Propulsion around Jupiter

[Whirligig Girl]

*note, still too loopy from dentist to give serious thought to this idea.

Would it be possible to use magnets to propel a spacecraft around Jupiter? Jupiter has a really big magnetic field You could rotate the magnet so that it's pushing or pulling the whole thing away from Jupiter.

Would it work?

Would it not work? Would it be more like Troll Physics?

(Yes, I went to all of the trouble to edits that picture just for this. That's not the spacecraft design I'm proposing, it's a joke)

Edited January 22, 2015 by GregroxMun

[Rakaydos]

Electrodynamic tethers.

Drag a long conductive wire through a magnetic field, you get electricity at the cost of speed. Pump electricity back in, you get speed at the cost of electricity.

[Streetwind]

The question is how much electricity you need for a certain thrust with an electrodynamic tether. "Newtons per kW", so to speak.

This is important because Jupiter receives only 4% of the sunlight that Earth does. This makes generating significant amounts of power rather tricky. NASA's Juno spacecraft is the first Jupiter mission to ever rely on solar panels; it has the largest solar array of any NASA probe ever. And they're fairly modern, high-efficiency panels (it launched in 2011). But despite that, it will still have to make do with only some ~450 W worth of power. That's not enough to run even a single NSTAR ion drive at a quarter throttle... not to mention that the rest of the probe and its many science instruments also need power.

Previous missions used RTGs, which also only generate a few hundred watts.

For electric propulsion - any kind - to work at Jupiter, we need way better methods of power production.

[parzr]

Perpetual motion machines won't work on Jupiter any more than earth. Anything that gets power must give it back somehow and without 100% efficiency will drag.

[micha]

We have better ways of power production. Look at all the old probes using RTG's. Proven tech. And there's plenty of designs (some even flown) of full nuclear reactors. But the rabid anti-nuclear lobby is putting paid to that.

[Nuke]

Perpetual motion machines won't work on Jupiter any more than earth. Anything that gets power must give it back somehow and without 100% efficiency will drag.

its not a perpetual motion machine. you need to pump energy into it to go anywhere. and it only works in the presence of a magnetic field, such as that around a star or planet. on top of that a number of tests have been conducted in space and the technology is at trl 6 (a notch above vasimr).

http://en.wikipedia.org/wiki/Electrodynamic_tether

We have better ways of power production. Look at all the old probes using RTG's. Proven tech. And there's plenty of designs (some even flown) of full nuclear reactors. But the rabid anti-nuclear lobby is putting paid to that.

lack of power supplies is the real hold up. solar is weak and only works close to the sun, rtgs are weak too. what we have is good enough for most one shot missions. but we have labs full of state of the art propulsion technologies that would revolutionize space flight if only there was a space worthy power supply that could output a few megawatts. only way nuclear would work is if we manufacture the fuel off world and just launch an empty reactor. compact fusion with direct conversion and we would colonize the entire solar system in a few hundred years.

Edited January 23, 2015 by Nuke

[Whirligig Girl]

Perpetual motion machines won't work on Jupiter any more than earth. Anything that gets power must give it back somehow and without 100% efficiency will drag.

Jupiter's magnetic field is the source of "infinite power" just like the sun. Both aren't REALLY infinite, they're just really really long lasting. Anyway, the design I showed was a joke, as I said in the OP.

[Streetwind]

Electrodynamic tethers are no joke though... they just need power like anything else.

[Rakaydos]

What I find interesting about electrodynamic tethers and jupiter, however, is parking one above Io and using the "turn my speed into electricity" option. By balancing jupiter's magnetic drag with Io's gravity, you effectively get free electricity, at least until the mass of the probe pulls Io out of orbit via gravity tractor. (so, not in a billion years.)

[peadar1987]

Using Jupiter as your reaction mass is pretty darn Kerbal!

[78stonewobble]

What I find interesting about electrodynamic tethers and jupiter, however, is parking one above Io and using the "turn my speed into electricity" option. By balancing jupiter's magnetic drag with Io's gravity, you effectively get free electricity, at least until the mass of the probe pulls Io out of orbit via gravity tractor. (so, not in a billion years.)

Hmm and how many tethers would it require to microwave transmit any significant amount of power back home or elsewhere where it's needed?

And wouldn't it then... possibly be better to build some kind of geothermal plants on Io?

[Streetwind]

Well, you can use that electricity for the probe itself, too. High-bandwidth communications home is very power hungry, for example. You could potentially run a far bigger antenna that can downstream large amounts of stored data very quickly every once in a while when the probe "parks" itself that way.

[Rakaydos]

Well, you can use that electricity for the probe itself, too. High-bandwidth communications home is very power hungry, for example. You could potentially run a far bigger antenna that can downstream large amounts of stored data very quickly every once in a while when the probe "parks" itself that way.

And once that probe has the capability, it can act as a relay for other jovian probes.

[jfull]

It would probably be more feasible than solar at the that distance from the sun, and wouldn't decay like an rtg