1107. Deployment Vehicle Mass Properties Model

Paper

Abstract

A comprehensive math model of a Deployment Vehicle has been prepared based on a Disc-type configuration. Equations and logic presented may be incorporated into other configurations with little or no modification. The developed model incorporates logic to:
– Select and size major Propulsion Subsystem Components
– Physically locate and define the mass and volume requirements for al1 major components (i .e. main and ACS engines , tankage, etc.) within the vehicle.
– Compute cg locations of a1 1 major components and the overall vehicle’s cg, moments and products of inertia.
– Define the vehicle’s shroud eject system.
– Compute the arrangement of various payload configurations within the geometric envelope of the shroud.
– Compute the most optimum deployment sequence, based upon overall vehicle cg and product of inertia.
The program, prepared in standard Fortran language, is designed to operate as a ‘slave” program (closed loop) when coupled t o a flight performance prediction model, or as a design program (open loop) for on-line evaluation of candidate vehicles. When operated i n the open loop, a performance event/time sequence is required. This sequence is derived from data generated by the earlier flight performance prediction runs and is uti1 i zed as a representative sequence. The program is divided into four major subroutines headed by a sequence routine which oversees and directs operation i n accordance with the subject instructions. The sequence also gathers and makes available to the subroutine all necessary data (from internal and/or external data files) as required by that subroutine. Cross-talk between subroutines is limited t o interrogation, and any answer which causes a change in an earlier-computed parameter results i n a recalculation of t h a t parameter.
The paper includes logic to aid in sizing of various engine requirements.