The objective of the Phase I SBIR project is to develop sensors that can discriminate the presence of combustible gases like oxygen (O2) in hydrogen (H2) or H2 in O2 backgrounds. These sensors will meet NASA applications for on-orbit crew and mission safety. Currently, H2 and O2 are produced by electrolysis of water. The O2 is used in the environmental control and life support systems (ECLSS) of spacecraft while the hydrogen is vented. H2 is a flammable gas while oxygen aids in combustion. InnoSense LLC (ISL) will utilize its Chemical Fingerprint (TM) sensor array fabrication technology in Phase I to engineer a miniature device with multi-analyte detection capability. The Phase I working model would be evaluated to demonstrate NASA use potential. Upon fine-tuning various parameters in Phase II, the system performance will be tested with a prototype hardware. ISL has received technology endorsement letter from a prime contractor in the NASA application area. For assuring success of this project, ISL has assembled a technical team with a cumulative 60 person-years of experience in developing commercially viable sensor systems.