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Structural/ propulsion instability

Pogo Analysis: Complex Dynamic Interactions in Rockets

Crean and Associates subject matter experts perform pogo analysis of 1st and 2nd stages of new Launch rockets.  Pogo is a behavior that occurs due to coupling of a liquid fueled vehicle’s propellant feedline modes of vibration with axial structural modes of the vehicle and is driven by the thrust feedback of the engine.  Axial vibrations create disturbances that travel through the engine and are manifest as thrust oscillations.  The resulting interaction can result in a system that is unstable.  If this happens, the resulting vibration can be extremely violent and can potentially cause loss of the vehicle and payload.

During a recent project, CREAN Launch, Missiles, & Propulsion team engineers worked closely with customer engineers to develop mathematical models and process test data.  In addition to flight analysis, a study of the stage as installed in a test stand was also performed to ensure that this system would remain stable.  Throughout this relationship, the CREAN personnel not only performed analysis, but also provided guidance and instruction so that the customer engineers learned both the physics of the problem and the software used in its analysis.  We are committed to not just helping solve problems, but also passing on our knowledge and experience.

CREAN.  For when it does take a rocket scientist.