Comment by southernplaces7
2 days ago
What you say is important of course, and it's what makes me less than sure in my assessment. It was after all more of a mental exercise in appreciating just how vast an area of space this relatively tiny quantity of objects is spread across.
To give one further perspective example here: a single large bulk container ship can carry up to 8,500 car-sized units.
This means that even if every single one of the maybe 15,000 satellites in orbit were the size of a car (most of them are much smaller actually), all together, they'd fill no more than the storage spaces of two bulk container ships with lots of room to spare at that.
This, spread over a multi-layered area as vast as our orbital space, means that even with their constantly moving at incredible speeds, and all the junk out there scattered between the satellites themselves, there's an enormous amount of emptiness between it all mitigating against impacts being very likely or frequent at all.
After all, of the 8,070 or so Starlink satellites in orbit right now, there's little mention of more than a few having been knocked out by debris in orbit. It seems that solar storms are their much bigger worry and cause of mishaps.
As the saying goes, space is huge, sometimes more than our brains can easily comprehend. This applies even in the comparatively tiny orbital regions of it that we use daily.
The mental exercise is fine for realising that satellites don't look as big as pictures of satellites in graphics, it's just missing the point that if you don't want to hit a 20cm x 20cm x 20cm cube that moves at 17,500 mph and has slow and limited capability to adjust that movement you need to allow it quite a bit more space, and be able to predict its movement accurately relative to yours. Especially if any collision means thousands of pieces of shrapnel that continue to move at 17500mph for decades or more, whilst potentially being too small to track but large enough to do a lot of damage.
Trains take up a negligible fraction of the mileage of the lines they operate on and rarely cross other lines, but signalling is still critical.
All of these are useful things to keep in mind of course, and they're why I put forth my consideration as a thought experiment for perspective, not so much as an absolute assertion. Orbital space is complicated, and the the ramifications of accidents are extremely unique compared to those that apply in a terrestrial context, but I still stand by my point about it being absurdly big enough that a sense of proportion is needed in worrying about something like Kessler syndrome.