Engineering criteria for spacecraft cabin atmosphere selection. NASA CR-891.
D000388:Air; D001274:Atmospheric Pressure; D018504:Ecological Systems, Closed; D004738:Engineering; D005390:Fires; D006371:Helium; D008021:Life Support Systems; D009584:Nitrogen; D010100:Oxygen; D013026:Space Flight
D006371:Helium; D009584:Nitrogen; D010100:Oxygen