Hacker News new | ask | show | jobs
by mayama 4 days ago
In case of collision in LEO, wouldn't the debris have chance to go high altitude and cause further collisions?
1 comments

No. It'll stay in essentially the same orbit.

During collision, some of the energy will be lost, so the fragments will necessarily have a lower orbit.

The only thing that can accelerate fragments into a substantially higher orbit is the energy of elastic deformation of material during the explosion.

Can’t two solid object with equal kinetic energy collide in such a way that most of the energy goes into one of them, giving it a velocity that boosts its orbit while the other one has lower velocity and de-orbits?

Or one object explode into two fragments, equal and opposite relative velocity, again pushing the one half into a higher orbit and de-orbiting the other half?

(Honest question, math major, never took orbital mechanics or played KSP much).

> Can’t two solid object with equal kinetic energy collide in such a way that most of the energy goes into one of them, giving it a velocity that boosts its orbit while the other one has lower velocity and de-orbits?

Sure, you can. Imagine shooting a bullet into a tungsten cube. The cube will go into a higher orbit, and the bullet will bounce back (and maybe de-orbit).

But the kicker here is that for this to work, the bullet has to be in a _higher_ orbit than the cube initially. So the end result is still fewer objects in higher orbits.

Another option is momentum transfer via elastic deformation - you shoot a bullet into a 45-degree facet of that tungsten cube, and the bullet then ricochets into a higher orbit. It ultimately works by momentarily storing the energy of the projectile as a plastic deformation of the facet. So it can't accelerate more than a few small fragments.