[extropy-chat] Pluto New Horizons launch -getting ready

[spike]

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org [mailto:extropy-chat-
> bounces at lists.extropy.org] On Behalf Of Alejandro Dubrovsky
...

>  The crater
> > will end up being about five meters deep, with its diameter a function
> of the mass and speed of what used to be the impact lander.
> 
> Thanks for the excellent explanation, Spike.
> A query:  The incoming energy is provided by the kinetic energy of the
> lander, which is proportional to its mass. The energy is going into
> vaporising it, which is also proportional to its mass, but some of the
> planet is getting vaporised too, and the more lander there is, the more
> planet that is going to get vaporised (if I read your explanation
> correctly).  Wouldn't this vaporisation energy then, at some large
> enough lander mass,  be above the kinetic energy of the lander?


Good question thanks.  You are right: it is a puzzling output of the finite
element sim they were running, but it makes sense.  Above a certain
velocity, the mass of the projectile did not result in significant change in
the diameter of the hole.  The length of the projectile is directly
proportional to the depth of the hole and the projectile velocity is
directly proportional to the diameter of the hole.

The equations all get much simpler above about 3 km/sec.

spike