On that note, I wonder what the impact velocity of the Nickel/Iron meteor
was that made the Barringer crater in Arizona.
Ken
On Tue, Oct 5, 2021 at 8:50 PM George Herbert <george.herbert@xxxxxxxxx>
wrote:
Not Henry, but… as with ICBM warheads but to an even greater extent, KE
warheads want to keep their speed to impact (not all of it, but most).
Even ICBM RVs slow down as they descend, though modern ones are still very
hypersonic to sea level. Large KE weapons at 5-7 km/s down to sea level
have much higher retained velocity and maximum pre-impact Q. Much higher
thermal flux, pressure, pushing beyond ablation experience other than
Galileo’s entry probe.
I don’t think anyone has ever seen something at 6 km/s at sea level.
-George
Sent from my iPhone
On Oct 5, 2021, at 5:26 PM, roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
But still Henry, spacecraft re-enter just fine at the proper angle, why
not a kinetic warhead?
Ken
On Tue, Oct 5, 2021 at 1:05 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Tue, 5 Oct 2021, roxanna Mason wrote:
...Iron, maybe, but stone just bursts at high altitude...coating
Henry, I only heard Bob talk about the topic in general but I never saw
any plans if any existed. I assume the RV would have an ablative
or aeroshell to survive reentry. Bob was an accomplished engineer so I
think this was addressed satisfactorily.
Bob might not have known about it -- I think it was only more recently
that we came to understand that rocks have to be either quite small or
very large to avoid breaking up in the atmosphere. The issue is
structural strength, not heating: the stresses become quite large,
especially on a steep trajectory, and stone (natural or artificial) isn't
very strong except in compression. It can do its own ablating -- the
outer surfaces of meteorites are almost always melted, but the interior
stays cold -- but it's generally not strong enough.
Henry