Research and Technology 1998 Annual Report - Kennedy Space ...
Research and Technology 1998 Annual Report - Kennedy Space ...
Research and Technology 1998 Annual Report - Kennedy Space ...
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Environmental EngineeringSupercritical Air-Powered EnvironmentalControl Unit for SCAPEKSC uses the Self-ContainedAtmospheric ProtectiveEnsemble (SCAPE) for the safeguardof personnel h<strong>and</strong>lingrocket propellants. The existingconfiguration relies upon the useof a liquid-air-powered environmentalcontrol unit (ECU) thathas seen nearly 30 years of successfuloperation in support ofNASA <strong>and</strong> Air Force missions.The Category I configuration ofthis suit provides the user withtotally encapsulating protectionfor over 2 hours. However,several problems in the use ofliquid air have been identified<strong>and</strong> remain unsolved. Training<strong>and</strong> operational monitoring <strong>and</strong>constraints have safely controlledthese problems to date.A new initiative has begun forthe development of an AdvancedProtective Suit (APS) that willmeet future mission supportneeds in an environment that isexpected to impose even lowertoxic threshold limit values forhuman exposures. Initial effortshave focused on the remediationof liquid air system problems.Specifically, these problems aredependent upon (1) an uprightdewar (storage vessel) attitude,(2) an unstable or nonhomogeneousliquid mix where theliquid nitrogen component boilsoff before the oxygen component,<strong>and</strong> (3) the determination ofdewar quantity throughout theservice life when the ECU is on aperson’s back <strong>and</strong> in motion,which often is in an unusualattitude.A feasibility study of thestorage <strong>and</strong> use of air in asupercritical phase has beensuccessfully conducted in theBiomedical Laboratory at KSC.This development was an extensionof technology gained in aSmall Business Innovation <strong>Research</strong>project conducted byAerospace Design <strong>and</strong> Development,Inc., where a supercriticalair, positive pressure dem<strong>and</strong>,self-contained breathing apparatuswas designed. The SCAPEECU is a constant-flow systemthat supports respiration <strong>and</strong>cooling of the user. The new ECUstores 6.5 pounds of supercriticalair in a high-efficiency dewar <strong>and</strong>provides the air, after conditioning,to the suit air distributionmanifold. The prototype designwill be further modified to employa more effective liquidcooledgarment in place of aircooling. Problems with attitudesensitivity, stability of the gas,<strong>and</strong> quantity measure have beensolved in this relatively lowerpressure, cryogenic, gaseoussystem.Contacts: D.F. Doerr (Don.Doerr-1@ksc.nasa.gov), JJ-3, (407) 867-3152;<strong>and</strong> M.B. Brown, FF-D2-D, (407) 867-718636
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