Abstract: An apparatus includes a scrubber bed, a cooling unit operatively connected to the scrubber bed, and a frame configured for a user to carry the apparatus. The cooling unit includes a compressor, a condensing coil operatively connecting the compressor to an expansion valve, and an evaporating coil operatively connecting the expansion valve to the compressor, and a first fluid circulating through the compressor, the condensing coil, the expansion valve, and the evaporating coil. A method of cooling a gas in a rebreather apparatus includes scrubbing an exhalation gas to produce a recycled gas having a lower concentration of carbon dioxide than the exhalation gas, compressing, condensing, expanding, and evaporating a refrigerant in a closed-loop system, transferring heat energy from the recycled gas to the refrigerant, and metering a cooled gas to the user.

Abstract: An apparatus comprising a scrubber bed; at least one heat sink operatively connected to the scrubber bed; at least one screen connected to the scrubber bed; and a scrubber tube connected to the scrubber bed. Also, a method of using a multiple mission re-breather apparatus, the method comprising attaching the multiple mission re-breather apparatus; using the multiple mission re-breather apparatus in a dry environment; and using the multiple mission re-breather apparatus in a wet environment. Further, a method of controlling a multiple mission re-breather apparatus, the method comprising activating an electronics package of the multiple mission re-breather apparatus, the electronics package comprising software instructions for adjusting operational parameters of the multiple mission re-breather apparatus in response to a change in environmental pressure; and using the multiple mission re-breather apparatus.