Not sure if something like this has been posted. But how about a pump sort of thing that pumps out void, void being the airless enviroment using the same physics as water. Oxygen when oxygen is exposed to void will be changed to void The main purpose of this suggestion is so that people can have bases in airless places. A oxygen pump that places oxygen around it but only in enclosed areas and void vacuum that make void withing X amout of blocks or only in enclosed areas they can be powered by switches or something like that you could also use the airlock door to prevent your oxygen/void from escaping.
