Active-Passive Acoustic Absorber for the Scorpius Launch Vehicle

We propose to build and test an active-passive acoustic absorber for the Scorpius(TM) launch vehicle. The absorber is designed to couple into the first few acoustic modes of the payload fairing cavity. Mechanical designs are tuned to the lowest frequencymode and the higher-frequency modes are attenuated with feedback control. Suppression of the first few acoustic modes will reduce the sound pressure level inside the fairingcavity and reduce the vibroacoustic loading on the payload. Previous workby the proposing firm and their subcontractor (Boeing-SVS of Albuquerque,NM) has shown that a 4 db to 8 dB reduction in overall sound pressure levelbelow 300 Hz can be achieved with dissipative feedback. The acousticdissipation is maximized through an automated tuning algorithm thatidentified the resonant modes of the cavity and automatically tunes thecontrol parameters to maximize damping. Tasks associated with thiswork are (1) mechanical design of the absorber housed in the Scorpius (TM)launch vehicle, (2) design of control and power electronics, and (3)system integration and delivery for acceptance testing. Although this Phase I schedule is aggressive, the chance of demonstrating feasibility is maximized by using a previous design as the baseline forth Scorpius(TM) absorber. Opportunities in the commercialization of active-passive absorbertechnology exist in the small, medium, and large launch vehicle market.Feasibility demonstration in Phase I will lead to the development of amodular absorber system that can be incorporated as an add-on into futureScorpius and Minotaur platforms. We will pursue agreements with OrbitalScience Corporation (the integrator of Minotaur) for the Phase IIdevelopment. Applications to larger launch vehicle platforms will bepursued in collaboration with Boeing through our partnership with Boeing-SVS.