Development of Validated Plume Signature Codes at Nontraditional Wavelengths Utilizing Ground Based Simulation Facilities

Physical Sciences Inc. (PSI) proposes to utilize ground-based simulation facilities to obtain the critical data necessary to validate plume codes extended to include Ultraviolet(UV), Visible(Vis) and Long Wave InfraRed(LWIR) signatures. These plume signatures include both a near-field component at all altitudes and a far-field component at higher altitudes where hyperthermal reactions with the atmosphere occur. In Phase I we propose to focus on phenomena associated with the far-field plume of the MonoMethylHydrazine (MMH)/N2O4 bipropellant thruster. We will use our tunable, hypervelocity oxygen atom source (6-12 km/s) to measure the velocity dependent cross section of oxygen atoms reacting with one component of the thruster exhaust. The data will be input to the plume code, SOCRATES/P, and the plume radiance from the candidate reaction will be calculated under several scenarios. In Phase II we plan to examine phenomena and signatures associated with both the near and far-field plumes of a thruster technology of critical interest to MDA. Measurements in the near-field may include characterization of the absolute spectral radiance in the LWIR and/or UV/Vis as a function of engine characteristics (start-up and shutdown transients, Oxidizer/Fuel ratio). The far-field measurements will include characterization of the velocity dependent cross sections of additional far-field reactions.