Laser-Induced Emission Sensor for Health Monitoring of Hydrocarbon Rocket Engines

A non-intrusive sensor will be developed for detecting metals in the plume of a liquid hydrocarbon-fueled rocket engine for monitoring engine health. Conventional passive emission sensors have proven to be useful in the detection of metal combinations that uniquely identify a failing component in the engine. However, hydrocarbon-fueled rockets emit gaseous and particulate carbonaceous products whose spectra interfere with conventional plume monitoring methods. Laser-Induced Breakdown Spectroscopy (LIBS) can overcome these interferences by dissociating the carbonaceous species into their elements so they no longer interfere. The LIBS technique employs a simple design that can be made robust and compact by employing fiber-optic light delivery and collection, possibly leading to an in-flight sensor. The proposed Phase I effort will explore some key technical questions regarding the feasibility of a LIBS health monitoring sensor for hydrocarbon-fueled rocket engines. BENEFIT: The technology to be investigated in the proposed effort will be useful to companies and organizations involved in the development and testing of rocket and turbine engines. Air Force programs that could especially benefit are those involving the development of hydrocarbon-fueled rockets, including the Hydrocarbon Boost Technology Demonstrator Program and the Third Generation Reusable Boost Program. The proposed sensor system should enable substantial cost savings during engine development by alerting test engineers of impending catastrophic failures before they occur. An on-board sensor may allow even more cost savings since it would avoid the need for extensive testing and examination of an engine during the turn-around period of a reusable launch vehicle. We will market our product to the Air Force, NASA, and companies developing rocket and aircraft engines. The primary market will initially be research organizations, but will expand into commercial online engine sensors after further development.