What I'm waiting for is orbital unlauch vehicles. That is, spacecraft that methodically collect and comoactify space debris.
As we launch more and more cheaply and frequently, the few thousand miles above Earth become littered more and more, even with all deorbiting or parking provisions.
What is the distribution of the time scale of these orbits though? If 90% of these things take a couple months (or weeks or days or whatever) to decay and burn up it seems like a non-issue - or one that can be planned around. If the fat tail sits further out in time that seems like it could actually become an issue.
One of the junkiest places in orbit right now is around 800-1000km (mostly thanks to the Chinese ASAT weapon test 12 years ago and an unrelated collision between two satellites in 2009. There's also tens thousands of droplets of irradiated coolant that was ejected from Soviet nuclear reactors in 70s-80s). At 1000km it can take around 100 years for something to deorbit from drag (can vary a bit depending on unpredictable space weather events).
1000km is still in Low Earth Orbit, but lower parts of LEO decay more quickly, e.g. months years or decades depending on the orbit's height.
When you get into orbits higher than LEO (MEO: medium Earth orbit, GEO), the timescales before something reenters can get more geological. A GPS satellite (~20,000km up, near the middle of MEO) left to its own devices will stay up for hundreds of thousands, if not millions of years.
Thanks for the detailed response. Fascinating. Where do you come across this information? I’d also love to learn more about this nuclear event from Soviet spacecraft.
Some of my coworkers do work related to orbital debris. I've learned a little bit by osmosis (mostly the right jargon to type into Google to get useful query results).
The Soviet spacecraft were the slightly confusingly named US-A series, also called RORSAT in English. The Wikipedia article[1] is a good start, but you can find some more technical info if you search around for papers on "NaK droplets"
As we launch more and more cheaply and frequently, the few thousand miles above Earth become littered more and more, even with all deorbiting or parking provisions.