Talk-Polywell.org

http://www.flightglobal.com/articles/20 ... ncher.html

So I have been toying with this idea for two and a half decades now. All I ever got to hear was "that wont work because the plasma during reentry is neutral". Now someone is doing it anyway. Guess it was not that stupid an idea after all.
My thinking always was: You dont need to reduce the heatload by 100% for this to make sense. Just enough so you can use a more lightweight passive TPS instead of the heavier ones. That might already be enough.
Guess the russians think the same thing.
I think that this kind of system would be very useful for VTOL vehicles that have less drag than winged counterparts and therefore experience more heat during reentry.

I also wonder about stability of the vehicle in reentry. The pressure on a physical heat shield is fairly even. A magnetic shield would be like riding an air mattress through the atmosphere.

I guess that that depends on the shape of the magnetic field, no?
Also, I think that there will still be plenty of contact with the air, just not as much as before (reduced enough to reduce the heatload to more manageable amounts). That is what I believe anyway.

Not only the shape, but the dimensions too.
The bigger the shield surface the less the thermal load for square cm will be.

I never tought about using a magnetic field as a shield, is an interesting idea indeed.

Interesting.

A study a few years ago supposedly figured out that a fairly weak magnetic field around a crewed spacecraft would significantly protect the crew against charged particle radiation. Previously it had been assumed the field required would be huge.

Orientation was important. That particular drawing shows a simple solenoid that would point a cusp at the nose of the vehicle.

Could such a shield be self-generating? Use MHD to power the field that protects the craft?

Use MHD to power the field that protects the craft?

Hmm, that would be cool I am not sure though that this would work. You would have to use the same interaction to power the shield that you actually want to avoid with the shield. At least thats what my gut tells me.

Hey, I shopped the basic idea arround at the alt.space groups multiple times and at point was already told to shut up and go into a corner. So I never got to the point of wondering much about the power question.
I guess for the test in the link the super conductor is doing the job well enough.
Maybe a super capacitor or a small nuclear reactor would work too?

"A Magnetohydrodynamic Power Panel for Space Reentry Vehicles"

http://utias.utoronto.ca/~csteeves/pape ... n-2007.pdf

"The analysis shows that a magnetic system weighing approximately 110 kg can generate 0.6 MW of power for 1000 s."

Yes, that's what I was thinking of. MHD power generation has been studied for decades.

The problem of generating power for a re-entering spacecraft is what the heck to use all that power for if the mission will be over in minutes. The magnetic shield would be a good answer,

But thinking about it I came up with another possible use, so I scrolled down to the end and was not surprised to see that was a DARPA project. The other thing you would want a lightweight high-powered system for on a re-entry vehicle is a death ray.

I was thinking of big paddle wheels on the sides. Think how fast they'd spin!

Well, it's a fun mental image anyway.

I was thinking of big paddle wheels on the sides. Think how fast they'd spin!

Problem here is weight and drag for launch. For reentry that might actually be working
Ever heard of the Roton? It is not quite paddle wheels, but pretty close (direct your attention to the tip of the vehicle):
http://www.astronautix.com/lvs/roton.htm