Risks for the space station

We actually do run that risk. We have about a 2% chance of catastrophic failure of the space station from running into a piece of grit against which we can’t defend. The Space Station is defended against objects up to about the size of a pea moving at up to 11kms a second. We can manoeuvre out of the way of things that we can see which typically are the size of maybe of a softball to a rugby ball, anything bigger we can see in orbit, and can predict days ahead of time if we will be likely to collide with it and we move out of the way. But it’s that small population of things that are smaller than a softball and bigger than a pea that we cannot see and will actually puncture our space craft. We run a 2% chance over the life of the space station that we will have an injury causing accident to micrometeorites.