Sat collision highlights importance of picking up your toys

The Beeb is actually a lot less Chicken Little about this than most other outlets, but even it's a little wonky. With that many satellites, it seems surprising there aren't more collisions, but living in shallow 3-d we have an inaccurate perception of how big space (any space, not just the black-and-airless kind) is once you get your feet off the ground.

We only perceive the space around us, usually in the space that extends from our eyeline to about waist level (that's why people trip on things that are easily visible but are below knee level, unless they see them while still relatively far away). So anything we perceive as "near" is usually on that plane and within a distance that changes based on the size of the object and the speed with which it or we are moving. Excellent perceptual basis for a creature that once climbed in trees and needed to be sure where the stable branches were, but was a lot more comfortable not thinking about the distance to the ground.

Once you get more than a body length off the ground, though, the volume of space around you increases by orders of magnitude (Add a zero to whatever number you were thinking.)

When you get up as high as orbit, it's a challenge just seeing something that's near enough to be a danger. The International Space Station is 270 miles below the satellites that collided. And it's not directly below. It's somewhere on a giant sphere whose radius is 270 miles smaller than the one the satellites are sitting on (geometrically speaking, of course, where the spheres are the distance from Earth that equates with their orbits. Here's a decent illustration.)

The two sats are each about the size of a smallish car, 528 miles above ground. That's a lot of space to fill. And pretty long odds against anything hitting anything else by accident.

The collision between a US and Russian satellite in space highlights the growing importance of monitoring objects in orbit.

It also shows that there are still major capability gaps in current systems set up for this task.

There are about 17,000 man-made objects above 10cm in size that orbit Earth - and the tally is constantly increasing. This in turn raises the risk of collisions between objects. ... rest of the BBC story is here