Personnel at the Kennedy Space Center are required to handle highly toxic rocket propellant during ground operations. Fully encapsulated suits provide respiratory and skin protection. These suits, however, can cause significant heat stress during warm-weather operations. A supercritical air-supplied Environmental Control Unit (ECU) was designed and is being tested to replace the existing liquid air-supplied units in an effort to eliminate oxygen enrichment, attitude dependence, and lack of quantity measurement. An air distribution vest was also designed and is being tested as an improvement to the current air distribution system. It is hoped that integration of both designs will enhance performance of this propellant handler’s ensemble (PHE).

Key accomplishments:

• Supercritical air ECU operates in all positions, without oxygen enrichment.
• Supercritical air ECU provides air for 2-hour suited timeline.
• Air vest designed to concentrate available ECU cooling air on the torso.
• Testing accomplished on four subjects in 74- and 110-degree-Fahrenheit (°F) environments.
• Created a standard testing protocol for fully encapsulated garments.

Key milestones:

• Determine most efficient and supportable heat stress countermeasure for suit. This could be the existing hose manifold, the new air vest, or a liquid-cooled garment.
• Establish demand breathing to decrease weight of air carried and eliminate carbon dioxide.