SpaceX satellites are doing about 1000 collision avoidance maneuvers every single day. The addition of new networks is going to congest things even more and the risk of unavoidable cascading failure keeps increasing at a massive rate.
Those are pre-emptive moves for minimizing what is a very small chance of collisions, not narrowly escaped near certain collisions. Air traffic control does a similar thing with keeping planes spaced apart in zones under their control. In space a small thruster nudge will have a huge impact at a very low cost
That depends what you mean by "open ocean"? Vessels near ports or in defined traffic lanes frequently maneuver to avoid collisions as per the rules of the road. Outside territorial waters it's less common but still happens occasionally. Either way, those avoidance maneuvers are such routine events that no one really gathers data on them.
Loads of those result in crashes with some involving hundreds of cars.
Just one collision in space carries an ever-increasing risk of cascading into a major event with long-term effects (there's no a good way to call in a space wrecker to haul billions of tiny bits out of orbit).
Debris from a collision on water won't spread out into millions of floating pieces that speed around faster than a bullet, ripping random ships on the other side of the world to shreds.
> spread out into millions of floating pieces that speed around faster than a bullet, ripping random ships on the other side of the world to shreds
This isn't how debris clouds work. The most-complex ones occur when entirely separate orbits collide were you get an X-shaped (versus cylndricla or conic) debris cloud. But the energies of the collision inputs sharply curtail the orbits and places in said orbits the debris fragments can generally reach.
Idk, Iridium-Cosmos debris are still absolutely everywhere [0] after almost 20 years. The only place a ship collision's gonna leave debris is directly under it.
Space is big. Volume grows with radius in a way our intutiions don't seem to intuitively understand. Yes, debris in a space collision go further. But they're still bound by their energies. And that larger volume of collision debris (plus all other stuff in orbit minus the Moon) is still a smaller fraction of the orbital space than e.g. commercial air space on earth, and yes, that's including oceans.
Space is huge, but being on land has some advantages too. It's true that volume grows, but satellites don't have brakes in the way that cars do, nor is there a cleanup crew that removes the debris after a crash.
You can remove curbs and any other barrier to simulate the fact that cars can maneuver away from a crash site, but if no site is ever cleaned, and no car has meaningful brakes, crash sites are much scarier.
