Description: Makel Engineering, Inc. proposes to develop a miniaturized Multi-Species Chemical Microsensor Instrument suitable for real-time, in situ measurements of hydrogen or methane, oxygen, water vapor and mixture thermal conductivity for monitoring purge effectiveness in cryogenic propellant lines. Helium is a scarce, strategic and non-renewable natural resource. NASA is a major user of helium and significant future cost savings in operations can be realized with improved monitoring of purge activities. Without real time measurement of species being purged from systems, extended purge cycles and excess helium is used to ensure completely purged lines. The proposed sensor system will incorporate individual microsensor elements for key species. The sensors will be designed to be permanently installed in purge and vent lines at cryogenic propellant storage, transfer, test stand and launch facilities. The instrument package to be developed in the program will adapt low cost and low power chemical microsensor technology which was originally developed for leak detection applications and recently been demonstrated in proof of concept cryogenic vent tests at NASA. This program will develop a low cost, robust integrated sensor probe and electronics with data interfaces suitable for real time monitoring and control helium purge sequences to minimize overall helium usage.

Benefits: The primary NASA application of the technology will be at propulsion test stands at NASA SSC and NASA Launch facilities at NASA KSC. The proposed sensor product would be used in systems for propellant storage, transfer and fueling operations. The use of these sensors would be part of an overall operation and maintenance strategy to reduce helium purge gas usage and reduce facility operating costs.

Commercial space transportation and spaceports will require operations to be highly automated and efficient to achieve the desired levels of cost effectiveness. The proposed MCMI will be immediately applicable to new facilities being planned and existing facilities undergoing modernization and upgrades. There is also a large opportunity for variations of the MCMI for monitoring a wide range of industrial processes such as gas-to-liquid plants using natural gas. Chemical processing and refining operations use purge gas systems with nitrogen during change over operations and maintenance cycles. Currently many industrial operations rely on personnel to do manual sampling and monitoring at various points in the system with portable analyzers during purge operations.