Spectral Measurement System for Health Monitoring of Liquid Rocket Engines

ABSTRACT: 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, optical measurements to enhance engine health monitoring are desirable to support this need. During Phase-I OKSI successfully demonstrated reliable detection of metallic species on a liquid rocket engine (LRE) using passive emissive spectroscopy. As opposed to active methods (LIBS, LIF, etc.), passive emission spectroscopy is the most attractive concept due to size, weight, and power and cost (SWaP-C) as well as being fundamentally robust. During Phase-II OKSI will develop a brassboard Optical Sensing System (OSS) which epresents a flight qualified system (small, light weight, low power, high reliability, ow cost). Integrated near real-time software will be developed to automatically detected he presence of metallic species against complex plume background emission signatures e.g., hydrocarbon molecular emission). The integrated hardware / software system will be demonstrated on controlled lab-scale engine tests where numerous failure modes can be induced. The OSS will also be demonstrated by piggybacking on sub-scale and / or full-scale static engine firings. OKSI will coordinate with organizations specializing in engine health management to establish proper interfaces between the OSS and the engine health management system. At the end of Phase-II, OKSI will be prepared to integrate the OSS with the engine health management system and conduct hardware-in-the-loop testing as well as static engine fire testing. 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. An enhanced engine health monitoring system technology developed can 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 cripple the US operational ability when unique payloads are lost.