> If you cooled the mixture at low enough temperature, you'd stop it from burning (like when you pour water on top of a camp fire), but it's not clear how you're supposed to do that in a spaceship where you can't carry a few tons of water for your sprinklers.

Also water would make it hotter, given this is liquid oxygen.

There are other methods too, e.g. fire inhibitors (like Halon or whatever is allowed now) or shockwave to disrupt fire boundary. But I doubt they are very practical on a spaceship.