Preliminary sizing of parachute systems

This work is focused on the development of an easy handling, quick, and reliable tool for the preliminary sizing of parachute systems. The tool also includes the capability to check the proposed design by performing a descent phase trajectory calculation. The preliminary design is based on the system requirement (vehicle mass and maximum acceleration induced by parachute), and mission requirement (descent system triggering condition and landing final conditions, vehicle aerodynamic drag). The outputs of the preliminary design include: • Number of stages and end conditions for each of them • Preliminary geometrical sizing for the identified parachute • Preliminary materials selection and mass budget definition for the selected parachutes A set of dedicated database related to type of parachutes (including scaling geometrical factors and deceleration characteristics)and material properties (strength and mass) have been integrated in the model. Also simplified atmospheric has been included to extend as much as possible the applicability of the tool. Databases have been built on the basis of the data available in the technical literature, but can be updated in case more data are available. Preliminary material definition is based on the results of the stress analyzed performed for the different element of the parachute. A 2dof descent trajectory model has been included to check the parachute sizing and identify a preliminary timeline compatible to the system requirements. Sizing case to validate the tool have been selected on the basis of the data available in the open scientific literature. Results obtained show a good agreement respect to the reference cases.