> US rocketry has a tradition of making second stages dispose of themselves after their work is done. AFAIK no regulatory body enforces this - but launch providers usually do it anyway.
The FCC individually licenses every launch, and explicitly cares about collision risk. I'm not sure if there's a specific rule about when second stages must be deorbitted, but I'm pretty sure that if a launch provider intended to leave a second stage in a crowded orbit the FCC would cause trouble for them.
Also even if/when there isn't an actual regulation, it is to your benefit to act as if there is one and keep things "clean enough". If things never reach the point of regulators getting interested you can choose how to follow the intent and ensure regulations you hate don't get in. (once regulations you need to spend money on lobbyists to capture and write the regulation, cheaper to not get that far in the first place)
Of course the above is a game of prisoners dilemma. You are risking others defecting first. In the current situation there doesn't seem to be much cost if you are last to defect (since regulations will come in just a few rounds). In other situations there can be great gain in defecting first.
If you're in this situation, you can guide how that regulation is created though so that whatever your current situation is can be the cutoff levels in the regulations.
True but others also have input. This can help or hurt you depending on what they want and relative powers between them.
do those others make matching contributions to election campaigns?
The FCC deals with the comms for a rocket launch, but I think its the FAA that deals with the actual rocket stuff you are talking about.
Edit: I stand corrected!
The FAA does have licenses over launch and they are trying to impose rules for upper stages of launch vehicles [0]. The FAA said they would complete these regulations in 2025 [1], but I haven't seen something saying they have gone in to effect yet.
The FCC does deal with disposal requirements for US satellites that are launched. In order to secure a license from the FCC you have to prove that your satellite will meet the latest guideline that it will be disposed of (either de-orbit for LEO, or moved to disposal orbit for higher orbits) within 5 years after mission complete [2]. Unfortunately this doesn't seem to apply to upper stages for some reason even though I would say that it is an orbit object that gets licensed and would "complete the mission" after deploying the satellites and have to abide by the 5 year rule.
[0] https://www.faa.gov/newsroom/faa-proposed-rule-would-reduce-...
[1] https://spacenews.com/faa-to-complete-orbital-debris-upper-s...
[2] https://www.fcc.gov/space/faq-orbital-debris
It is the FCC[1]. The FAA is only concerned about the launch and de-orbiting as it passes through airspace, and doesn't regulate what happens between, including whether object de-orbit at all. It is odd for the FCC to have this responsibility. They kind of picked it up by default since they were the only agency regulating operations in space in any way, and we had ratified treaties that needed to be enforced, without creating an agency to enforce them.
Edit: The FAA is also proposing orbital debris rules that were supposed to be finalized this year, but aren't released yet[2]. This whole area is a mess, and really needs congress to set clear responsibilities.
[1] https://www.fcc.gov/space/orbital-debris
[2] https://spacenews.com/faa-to-complete-orbital-debris-upper-s...
For the actual current rules about collisions and debris broadly see: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B...