The broader impact/commercial potential of this project will be a safe and robust real-time O2 monitoring instrument for aircraft fuel tanks. This instrument will benefit the commercial aircraft industry by dramatically decreasing the probability of fuel tank explosions on planes and potentially save lives. This technology could also be used to insure that military plane and helicopter fuel tanks are adequately purged after they are pierced by ballistics, protecting both the aircraft and military personnel onboard. In addition, the technology developed by this project might be used to monitor the ullage in oil tankers and reservoir to prevent explosions, greatly benefiting oil industry and preventing oil spills. Finally, because this technology makes measuring O2 in harsh chemical environments possible, it might be applied to monitor O2 in the pharmaceutical and specialty chemical manufacturing process, where reduced O2 is often critical to protect expensive catalyst from fouling. <br/><br/><br/>This Small Business Innovation Research (SBIR) Phase I project aims to develop a safe and robust real-time O2 monitoring instrument for aircraft fuel tanks. Such an instrument is needed to address mandates from federal transportation safety agencies, which require commercial aircraft to eliminate the possibility of fuel tank explosions. The proposed instrument advances the state-of-the-art by employing a multi-component optical sensor based on the fusion of optical oxygen, temperature, and pressure sensors. The combination of these three robust, stable and sensitive sensors allows us to accurately and precisely measure O2 concentration in the range of temperatures, pressures and concentrations found in aircraft fuel tanks without the risk of spark hazards. The goal of Phase I will be to develop a prototype O2 monitoring instrument for aircraft fuel tanks and demonstrate that our technology can make safe, precise, and accurate O2 measurements in jet fuel vapors over an extend period of time.