The other robert wrote:

RobertS
random thoughts
Sat Jun 16 13:40:25 2001

I recall reading about similar concepts being applied to "dust-catcher" missions to pick up interplanetary dust. I seem to recall that the gap between plates was filled with aerogel, which apparently is very effective at slowing down the secondary impact particle shower. Is aerogel being considered in these experiments? Or is it just too wimpy to make a difference at high velocity?

A question comes to mind that seems so obvious that I expect the answer is that somebody's working on it. Why a flat plate perpendicular to the direction of travel? It seems unnecessarily "macho" to absorb 100% of the energy and just "take the hit".

Why not streamline the geometry? I.e., concentric cones? The outer shield could dissipate some energy kinetically through deflection, saving on wear-and-tear; and the inner shield would gain the same advantage augmented by magnetic deflection.

Speaking of wear and tear, what kind of damage would the shield take on a multi-year/decade interstellar mission? You can't stop to make repairs, and I'd hate to be the guy who's EVA in front of the shield; for that matter, I wouldn't want to be in between the plates and hit with plasma!

Relativistic effects are interesting. It's potentially possible to impact a particle with a combined vector >c. I know, the velocity magically normalizes to exactly c, but would it be correct to calculate energy release e=mc^2 where c > 1?

--Robert


streamlining would require knowing from which direction the impactor was coming from. Not possible in space....

(as an addendum addition of velocities in relativity ensures that there will never be delta v>c)