DEVELOPMENT OF AN ATOMIC ABSORPTION SYSTEM FOR THE SPACE SHUTTLE MAIN ENGINE

Exhaust plume emission spectroscopy is a technique routinely used to monitor the health of the Space Shuttle Main Engine (SSME) and other rocket engines during ground testing at Stennis Space Center (SSC). The advanced technologies group at SSC has developed a plume diagnostic capability to analyze spectral emission data to provide the identification and quantification of elements and alloys in the SSME exhaust plume. The techniques, currently applied to all open air (ambient pressure, sea level) engine tests at SSC, allow spectral emission measurements to be made at the high temperature region of the exhaust plume. To provide the same capabilities on the A-2 and B-l altitude test stands, where the engine exhausts into a diffuser, experiments were conducted and a system was designed using atomic absorption spectroscopy (AAS) techniques. To date, the SSC atomic absorption system currently in use on the B-l test stand, has identified the elements Chromium (Cr), Iron (Fe), Nickel (Ni) and Copper (Cu) in the SSME plume.