Active Acoustic Absorbers for Launch Vehicle Payload Fairings

New and effective techniques of acoustic suppression are critical in lightweight composite payload fairings currently launched on expendable launch vehicles. The objective of this research is to develop a system of active acoustic absorbers to be integrated within payload fairings to increase acoustic damping and dissipate low frequency acoustic energy. In the Phase I feasibility of a system of three acoustic absorbers has been demonstrated with peak reductions of 9.7 dB using a single mode controller. New acoustic absorbers have proven effective in lowering global acoustic levels within a simulator of the Minotaur fairing. These absorbers provide the ability to target multiple frequencies within the volume while maintaining effective performance through robust control design. The Phase II will pursue advanced development of this absorber, lowering overall weight to below 2% of the payload allowance, while increasing structural integrity to make this system a viable option for launch applications. The system will progress through several generations of design and testing, and will be evaluated on both fairing simulators and a Peacekeeper-based sandwich composite fairing at AFRL. The final objective of this Phase II will be the design, fabrication and delivery of a system that could be tested under launch conditions.