Starfield Suit Protection Depleted explained and how to fix
Getting the Starfield suit protection depleted message is one of the most terrifying messages you can get in the game, at least if you're not sure how to fix it. That's because this change means that your spacesuit isn't going to protect you properly anymore, so you'll take a lot more damage.
Given that you'll generally want to avoid taking damage at all, let alone extra damage, you can see why this is such a big problem. Being shot already hurts; being shot with a depleted suit hurts even more.
Not only that, but you'll also end up gaining negative status effects if the environment around you is toxic too cold, too hot, or basically anything other than perfect. This is obviously bad, so here's how to fix it:
You're going to need to find an oxygenated area of some kind. This will allow your suit to effectively repair itself. There are areas like this dotted around on some planets in smaller sheltered sections, but generally speaking, your best bet is always going to be either going to a proper settlement of some kind or back to your ship.
Once you've returned there, you just have to wait for your Starfield suit protection to recharge, which doesn't take too long, and then you can go back out into the wilds to explore, safe in the knowledge that you're not basically running around naked.
If you're certain you'll be finished off before you get to a shelter, just open up the scanner and point it at your ship to be able to fast travel back there with no issues. This seems to work pretty much all the time, so make liberal use of it if you're in danger and don't want to die.