Spectral Measurement System for Health Monitoring of Liquid Rocket Engines

OKSI proposes to demonstrate the ability to detect metallic species in a hydrocarbon fueled liquid rocket engine (LRE) using high resolution emission spectroscopy. The detection of metallic species is an indication of engine wear and an early precursor to a catastrophic failure. During Phase-I, OKSI will conduct exhaust plume measurements of a sub-scale GOX/RP-1 rocket engine. Metallic contaminants will be added to the fuel prior to combustion. Two high resolution UV/VIS spectrometers will be fielded. A third MWIR spectrometer (which measures primary combustion products) will be fielded to assist in accurate modeling of the rocket engine. During Phase-II OKSI will conduct more extensive measurements using the same spectrometers. The measurements may be enhanced using Laser Induced Breakdown Spectroscopy (LIBS). High fidelity modeling and simulation will be performed using enhanced versions of the JANNAF engine/plume codes and other specialized signature codes. The Phase-II effort will culminate with the design, development, and demonstration of a ruggedized, high resolution spectrometer and data analysis system optimized for hydrocarbon fueled engine health monitoring. BENEFIT: The next generation military and commercial space lift systems will utilize reusable, fly-back first stage boosters to reduce cost. These systems must be quickly turned around for subsequent missions. Reliable, nonintrusive exhaust plume health monitoring is desirable to support this need. The technology developed under this project will enable the detection of metallic species, which is an indication that the engine may need maintenance. As such, the system developed under this program will have direct benefit to commercial space launch vehicles by improving the safety and reliability of the engines. The technology also has direct applications to commercial (and military) turbojet aircraft. The engine health monitoring system technology developed could be used as part of the engine check-out procedure, and once the system proves reliable, it could actually be utilized to reduce the required scheduled maintenance (downtime) for aircraft. Thus, in addition to increasing safety, an aircraft engine health monitoring system could also reduce operating costs. These abilities have the potential to prevent catastrophic failures at launch and save hundreds of millions of dollars when expensive payloads are lost. Failures also cripples the US operational ability when unique payloads are lost.