- oxygen generators
- electrolysis with water to split hydrogen and oxygen
 - electricity is from solar panels, water is delivered to the station from supply ships…
- water is also reclaimed from condensors that take water vapor from cabin air, and urine recycling
 
 
 - pressurized oxygen tanks
- are delivered from earth
 
 - solid fuel oxygen generators
 
future:
- plants would also supply air
 - limitation: space available