Astronomy/cosmology questions...

[Unorthodox]

Could y'all edumacate me about why they don't wrap something like a Faraday cage -or maybe just a silvered mylar envelope- around the ISS -or one whole module, anyway- and run a current through it for a radiation shield?  Same for traveling crew capsules, though I see that's a considerably greater engineering challenge...

Like, the big short-term threat is solar flares, right?  And that's a particle radiation problem, right?  And a large/intense enough magnetic field will handle particle radiation -if not the x, gamma, etc., wave radiation- nicely.  So, this is an obvious enough thing that I figure, with fair confidence, that there were pretty definitive theoretical/engineering studies done by the time I was born in the mid-sixties, and either the power requirements are prohibitive to do that for three days or so, or there's too much wave radiation in a flare - or both.  Help me out here, if you can...

ANYone?

Especially Lori, maybe Uno?

Mostly an energy requirement problem.  You'd need a significant magnetic field to be effective, and we just haven't unlocked the deflector dish yet.  (presuming it works on similar principle, I've read old star wars tech manuals, not trek) 

At present space travel is about conserving energy and trying to run things on as little as possible still.  Once we fully unlock in situ manufacturing that will likely start to change. 

[Unorthodox]

Didn't we talk about DART somewhere?  Thought it was this thread. 



https://www.livescience.com/space/asteroids/giant-space-boulders-unleashed-by-nasas-dart-mission-arent-behaving-as-expected-revealing-hidden-risks-of-deflecting-asteroids

[Unorthodox]

Ok found it.

It'd probably make for a more efficient/complete momentum transfer.

So, because I can, I asked some of the people with the papers that prove they're smart this question. 

It more or less boiled down into both sides presented here.  Some think it would actually BENEFIT the transfer of momentum, some think it would cause a loss of transfer as it's deflected to different vectors. 

With that said, those with the papers more specifically oriented to zero g stuff tended to agree with you that it would result in and increased change in momentum of the target but not because it was more efficient transfer on the initial impact, but because the ejecta would actually act as additional sources of thrust both when they left the surface and again when they eventually fell back to the asteroid, but also warned this would likely not be even so could cause spinning or slightly angular changes. 

(the more terrestrial papered folks tended to be adamantly opposed to this idea, which kind of leads me to believe it boils down to the level of gravity of the target object to really matter one way or another, but it's unlikely any target would ever hit that breaking point)

Either way it sparked a nice argument that got fairly heated at times and was generally amusing. 


All thought landing even a tiny engine would be more efficient for redirect...

So combined with the article above, it really sounds like the zero G guys were basically spot on in their theory of the increased momentum to the ejecta and causing weird angular stuff.  Fascinating.

edit, and somewhat confusing if my guys give it a cursory glance and cite this as a possibility why it's surprising to the nasa dudes...

[Lorizael]

edit, and somewhat confusing if my guys give it a cursory glance and cite this as a possibility why it's surprising to the nasa dudes...

Tony and Jess aren't NASA; they're my coworkers.

[Buster's Uncle]

When they did that power generation test with a conductive tether, the one that melted from all the juice it produced, any idea how much drag?  I never heard anything about that in the reporting...

Yeah, on that end... they measured a voltage of 3500 V and a current of about half an amp, so that's ~1750 W (Joules/second) being generated, which is drained from the shuttle's kinetic energy. Shuttle's mass was 10,500 kg and moving at like 7-8 km/s, which gives it roughly 300 billion joules of energy. So I think it would take a long time to slow it down appreciably by this method, unless there's some other factor I'm missing.

Y'know, it strikes me at this late date that there's a useful idea in there, if the engineering could be worked out - just, I was thinking about emergency power, when several orders of magnitude greater drag would be very valuable for leaving orbit w/o all that scary/dangerous reentry stuff, or at least less of it.

I suppose there's at least a half-decent science fiction idea there, supposing all the required gear weighs/bulks not-a-lot more than a heat shield would, and something useful to do with ~300 billion joules of energy in a tearin' hurry, or an impossibilium battery.  Either might have a significant impact on Elon Musk's cash flow...

It strikes that aside from the hypothetical possibilities for orbital braking -which I would like to kick around- this could also maybe be feasible more realistically as emergency power for emergency flare shielding, what with the RL braking effect being trivial for a vast amount of power generated.  If trivial drag, it could easily, if expensively, be made up for later, w/ healthier astronauts to show for it.  Needs an engineering study, I sez...