Positve Mask Pressure, Partial Rebreathing SCBA W/Body Cooling

The proposed breathing apparatus prototypes will primarily use the current design with the addition of the improved systems conceived of during Phase I. These prototypes will be one hour units and will have the same volume as half hour units of 4500 psicompressed breathing air. The supercritical breathing gas is single phase so that it will feed identically in any attitude, unlike liquid air. This is particularly important for underwater work as the attitudes are extremely variable. Because of themoderate or higher pressure the system will supply gas at any useable depth of dive. When out of the water the apparatus may be used for full respiratory protection against airborne chemical or biological agents. In addition, due to the cryogenic storageof the air there is considerable cooling capacity to reduce heat stress in the user during hot climate deployments or when wearing impermeable garments. For normal underwater operations the heat to warm the breathing gas will come from the surroundingwater, whereas for hot environment and land operations the heat will be supplied by the users body. The metabolic energy and heat transfer from the surrounding water is transferred to the breathing gas before it is consumed.Added features which could be investigated in the Phase II option would be to harden the system to military standards for electronics and periphial items. Another feature would be to develop improved human-machine interfaces. The supercritical cryogenic(SCC) SCUBA will have many commercial applications in professional diving and recreational industries. The greatly increased bottom time will be economically useful in photographic, salvage, and archeological work. The coolingcapability will allow diving in hot springs where time is now extremely restricted. With the addition of the option to provide a heating system in addition to the cooling the complete envelope of diving capability would be expanded into both thermalextremes.