How to use the Black Hole Particle Accelerator

First throw in a prograde spacecraft. It will become outgoing at the inner horion.

Wait for several orbits.

Then throw in a retrograde spacecraft, aiming carefully.

By adjusting the wait time, you can arrange that the two spacecraft collide at the inner horizon at whatever energy you choose. For the black hole at the center of the Galaxy, a wait time of 20 minutes will produce a Planck-energy collision.

A solar system flys by the black hole