"The mission control experts cannot tell if the space junk is going to hit the space station or not, but they are sure that a collision would knock a hole in the hull and cause all air inside it to quickly escape into space."
What does "would" give a particular meaning in this context? I think assumption/expectation is meant. They assume that a collision knocks a hole in the hull. They expect a collision to knock a hole in the hull.
Is it common the such usage of would?