Simulation techniques and analysis results for separation of the parachute container strap assembly cover from the descent vehicle using advanced software

The paper examines one of the most critical phases of the parachute system deployment during descent vehicle return to Earth, namely, the separation of the strap assembly cover with the extraction unit prior to the drogue parachute deployment. It presents some special aspects of simulating the motion of the system elements using advanced software packages FlowVision, Euler, Aero Shape-3D. A procedure was developed to simulate relative motion of the bodies in the atmosphere taking atmospheric interference into account. Dynamics of the cover separation in the wake was analyzed. An intensive spin-up of the strap assembly cover was discovered which may lead to the bridle and the extraction unit winding around the cover and the drogue parachute failure. The paper discusses the options for the cover design modifications in order to reduce perturbations during its separation.