The signature of rocket plumes can be used for detection, identification and guidance of rockets. The objective was to investigate the signature of various types of solid rocket propellants by application of spectroscopic methods. The emission and transmission characteristics of plumes were studied experimentally, the results were analyzed based on molecular bands and continuum radiation. The model formulations include a nitramine propellant, a double‐base propellant and a composite propellant. Applied were rapid‐scanning filter wheel spectrometers for the wavelength region from 1.2 μm to 14 μm with a time resolution of 50 spectra/s and a wavelengths resolution of 1% of actual wavelength. The UV/VIS wavelengths region was recorded by an OMA system with wavelength resolution of 0.1 nm and 1 nm and time resolution of 10 spectra/s. Molecular bands of water and carbon dioxide dominate in the near infrared and infrared. Depending on composition, continuous radiation indicates particles in the rocket exhaust. A code was developed to calculate molecular bands and continuous radiation using temperature and species distributions found by thermodynamic estimation to obtain the radiance of the plume. Comparison with experimental data delivered plume temperatures.

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Boron particle combustion is retarded by initial presence of an oxide coating. In current boron ignition models, oxygen is assumed to desolve in the oxide and diffuse to the B/B2O3 interface for reaction. One method to observe the reaction of boron with its surrounding atmosphere is the time resolved emission spectroscopy we applied in the range of 0.2 m̈m to 5.5 m̈m for different burning processes. In one experiment boron powder was burned in oxygen atmosphere initiated by an efficient pyrotechnic device. The energy transfer by the hot gases led to a glowing phase of the boron particles which then changed to a high temperature combustion and ended in a further glowing phase. The two glowing phases emitted continuous emission spectra, while the burning phase emitted the bands of BO and BO2. Another experimental setup was used to feed boron particles in a hot oxidizing atmosphere provided by a propane/air flame which flew into a combustion chamber. Herein the reaction of boron was recorded with high speed cinematography and time resolved emission spectroscopy. The flame contained a small amount of background radiation and we could identify emitted bands of BO, BO2, HBO2, CO and CO2.

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