[ExI] (NASA.gov) NASA to chronicle close Earth flyby of asteroid (fwd)

[spike]

On Behalf Of david

On Sat, 16 Feb 2013 19:10:40 -0800
"spike" <spike66 at att.net> wrote:

 
>> ...  Of course our intuitions fail 
> for we have little or no experience in real life with impacts at 20 
> km/sec... I would like to see a good simulation of it however.
> 
> spike
> 
> _______________________________________________


>...Hmm. thinking about it, if you hit the retreating side any momentum
transfer that did occur would probably be opposed by the change due to this
effect. Something else to consider before you shoot a rotating asteroid, you
want to hit the side that is rotating towards you for maximum delta V.
--David.
_______________________________________________


Before you go too far with it, think hard about that closing velocity, what
happens when you have impacts at 20 km/sec.  Intuition steers us wrong.  The
little bit of rotation goes away in the equations, negligible in comparison
to that enormous weird-zone of impacts at that speed.  I am reviewing what I
think I know about hydrodynamic impact regime, and I must retract my earlier
comment about punching a cone-shaped hole.  I need a good sim.

spike