Launch Vehicle/Launch Pad Separation Analysis

ASD personnel pioneered the widely utilized Henkel-Mar method (see ASD Journal Publications) of predicting the launch pad transient forces acting on the launch vehicle through engine thrust build up and launch vehicle separation from the pad. The time histories of these “decaying” forces can be significant to the launch vehicle and the accompanying payloads’ transient responses. During launch pad separation, the launch vehicle/launch pad system will undergo multiple system modal state changes, i.e., as various interface degrees of freedom separate, system modal frequencies will change, as will the system mode shapes. The Henkel-Mar method accurately captures all of the resulting system modal states via the use component modal synthesis methods. This is accomplished with invariant math models without having to compute intermediate system modal parameters, i.e., executing system level eigensolutions. With the Majed-Henkel extension (see ASD Papers), the lateral interface force decay can be coupled with the longitudinal force decay, thus constraining the forces to decay to zero simultaneously.