As the loads transmitted to satellite structures are reduced through SoftRide systems, the effects of acoustic energy have become increasingly important. When launch vehicles travel at high speed through the atmosphere into space, the turbulent boundary layers on the fairing or shroud exterior lead to high interior sound levels within the shroud in the vicinity of the satellite being launched. Additional sound results during initial liftoff as ground effects tend to accentuate the contributions of rocket exhaust beneath the vehicle. The high sound pressure levels cause satellite components to vibrate, possibly resulting in damage to those components.

To reduce acoustic loading on satellites, CSA has worked to develop a group of technologies known as QuietRide. The overall goal of this development is to present alternatives to the acoustic blankets traditionally used to reduce interior noise in launch vehicle payload shrouds. Using both passive and active approaches, CSA is aiming to provide improved performance with reduced weight.

CSA is developing the following technologies to attack the very difficult problem of launch noise attenuation:

• Integral damping within composite structures
• Augmented passive dampers and absorbers for structural and acoustic control
• Active structural control using piezoelectrics and reaction mass actuators
• Speaker-based interior active noise control and boundary control

Contact paul.janzen@csaengineering.com or roger.glaese@csaengineering.com with questions about QuietRide.

Launch Environment Mitigation
Technologies: Acoustics