A Software Simulation of Cargo Drop Tests

The NASA Johnson Space Center has developed a computer simulation able to predict and analyze the dynamics of cargo dropped with a parachute system. This simulation was developed to support a range of airdrop tests for the X-38 program. The X-38 program required a high fidelity simulation to model the dynamics of test article extraction from the carrier aircraft and subsequent inflation of the parachute systems. The simulation is capable of analyzing the forces and motion of the entire system from first motion in the aircraft until payload landing. The simulation was modified from an existing NASA software program for the Space Shuttle solid rocket booster recovery system design. The main effort in adapting the simulation involved development of the simulation models for the drogue parachute inflation, the drogue sling system, and the aircraft extraction phase. This paper describes the structure of the simulation and provides descriptions of the simulation models developed to support airdrop testing.