DURING THE PRELAUNCH CHECKOUT OF THE SPACE SHUTTLE, IT IS CONTINUALLY FLUSHED WITH DRY N(2) IN ORDER TO PREVENT THE BUILDUP OF AN EXPLOSIVE CONCENTRATION OF THE H(2) AND O(2) PROPELLANTS DUE TO LEAKAGE.

DURING THE PRELAUNCH CHECKOUT OF THE SPACE SHUTTLE, IT IS CONTINUALLY FLUSHED WITH DRY N(2) IN ORDER TO PREVENT THE BUILDUP OF AN EXPLOSIVE CONCENTRATION OF THE H(2) AND O(2) PROPELLANTS DUE TO LEAKAGE. IN ORDER TO DETECT ANY POSSIBLELEAKS, THE FLUSHING GAS IS CONTINUOUSLY SAMPLED TO MAKE SURETHAT THE H(2) AND O(2) CONCENTRATIONS ARE BELOW 500 PARTS PER MILLION. A MASS SPECTROMETER IS PRESENTLY USED AS A PRIMARY MONITOR. THE PROPOSED INNOVATION OF THIS PROJECT IS A RELATIVELY SIMPLE AND RELIABLE INSTRUMENT WHICH COULD SERVE AS A BACKUP MONITOR FOR THE MASS SPECTROMETER. THE H(2) AND O(2) IS DETECTED IN THE N(2) FLUSHING GAS BY A N(2)O-SENSITIZED ELECTRON CAPTURE DETECTOR, AND THE TRACE SPECIES WOULD BE SEPARATED EITHER BY GAS CHROMATOGRAPHY OR GASEOUS DIFFUSION. THE SUCCESSFUL COMPLETION OF THE PHASE I DESIGN STUDY PROVIDES THE FOUNDATION FOR THE DEVELOPMENT OF THE H(2)/O(2) MONITOR.