TFA says space junk shouldn't be a problem with the launch method they used
>SpaceX deploys its satellites into these lower obits so that in the very rare case any satellite does not pass initial system checkouts it will quickly be deorbited by atmospheric drag. While the low deployment altitude requires more capable satellites at a considerable cost to us, it’s the right thing to do to maintain a sustainable space environment.
The Gabbard diagram is a way of expressing the orbital locations and decay of the particles produced as a result of an orbital collision. Note how higher objects tend to stay high for a long time, but low objects (below about 600km) drift lower at an appreciable timescale, and once they're below about 500km they fall the rest of the way very very quickly.
Starlink satellites deploy to 550-km orbits.
Edit: Oh, these were launched into a 210-km orbit, which combined with the higher atmospheric density due to the geomagnetic storm, basically dragged them back down before they could raise to their normal orbit. Oof.
Even more strongly, SpaceX launches to a ~200km orbit and has the satellites raise themselves. This way any satellites without attitude control deorbit immediately.
Also, the vast majority of SpaceX satellites will be at 350km.
> SpaceX has two constellation applications pending FCC approval — one for a 4,425 satellite constellation operating in Ka- and Ku-band from around 1,200 kilometers, and another for 7,518 V-band satellites flying between 335 and 345 kilometers.
I am not aware of any Starlink satellites currently in either of those two orbits.
>SpaceX deploys its satellites into these lower obits so that in the very rare case any satellite does not pass initial system checkouts it will quickly be deorbited by atmospheric drag. While the low deployment altitude requires more capable satellites at a considerable cost to us, it’s the right thing to do to maintain a sustainable space environment.