[madaxe_again]

There are a great many eyes on the sky, and you can’t hide stuff up there - even every secret military satellite is known and tracked - so something as substantial as a collision would likely be known about before it even happens, as ephemera don’t change without an input.

[jacquesm]

Thank you for the answer. I'm aware of the degree of coverage over land but I was wondering about the ocean side of things as well.