Project Title:

A Subcritical Liquid Oxygen System

12.11-3200
912099
A Subcritical Liquid Oxygen System
Foster-Miller, Inc.
350 Second Avenue
Waltham
MA
02154-1196
David H
Walker
617-890-3200
JSC
NAS9-18666
258

12.11-3200
912099

Abstract:

A Subcritical Liquid Oxygen System
The present primary life-support system (PLSS) utilizes high-pressure gaseous oxygen
for operation. This presents a  significant safety risk and potential logistics problems
for future missions. The use of subcritical, liquid oxygen for the PLSS offers many
advantages, but previous attempts at using LOX have not succeeded due to such problems
as pressurization and dealing with a two-phase flow in a microgravity environment.
A subcritical LOX system that is capable of addressing these problems has been devised
while delivering the benefits of reduced system weight and volume (28 and 79 percent,
respectively) and eliminating the hazards of high-pressure oxygen systems. This system
employs a cryogenic tank equipped with a flexible bladder constructed from a liquid
crystal polymer (LCP) material, and a helium gas spring that maintains the LOX in
a subcooled state, preventing vapor formation, maintaining system pressure, and making
the tasks of metering and inventory measurement relatively easy.
Liquid oxygen is often used in military aircraft where the proposed system would
be an improvement over those now in use. Other mobile applications, such as underwater
activities, fire fighting, or medical emergencies, may benefit from this technology.
liquid oxygen, primary life-support, EVA, cryogenic