Filter (Oxygen)

The oxygen filter catches Oxygen. It fits any gas filter slot – the Filtration, the portable air scrubber and the suit. Its reserve starts at 100 and drops while filtering; in the filtration unit you read it through the slot logic value Quantity.

It lets you win breathing gas from mixtures:

• Electrolysis: the Electrolyzer releases oxygen and hydrogen together from one output. An oxygen filter in a filtration unit separates them.
• Europa: according to the world data the atmosphere consists of oxygen only – at about −140 °C, though. You hardly need to filter there, but you do need to warm it up.
• Mars: the air holds only about 1.4 % oxygen. You will not get much out that way; oxite ice is more productive there (22.5 mol of oxygen per piece).

How much you need: for 22 % oxygen in a room of four cells at normal pressure it is about 293 mol. For breathing the partial pressure counts – from 16 kPa of oxygen you breathe at full efficiency.

Think of fire: oxygen is an oxidiser. A filtered oxygen stream must not meet fuels such as methane or hydrogen, or a spark is enough. Diluting with nitrogen does not make a mixture non-flammable in the game.

Lifetime: every 145 ticks in which it actually catches oxygen cost 1 point of reserve – 100 points last a good two hours of continuous use. It takes liquid oxygen along too. The medium filter lasts about five times, the heavy one about twenty times as long; like the normal one, both are made in the Hydraulic Pipe Bender. The catalytic one (about eighty times as long) is only available from the trader Cosmic Curiosities. More in Filtration: separating gases, changing filters, getting rid of waste gases and Electrolysis and water: winning oxygen and hydrogen.