Study on the ditching of space capsules using the smoothed particle hydrodynamics method

Abstract

Spacecraft ditching on the water surface is a classic and widely concerned problem in aerospace and marine engineering. Researchers have carried out many experimental and numerical investigations to explore the slamming load and the stability of the ditching trajectory. The δ+-SPH model is adopted in this study to simulate and analyze the load and motion characteristics of a capsule after entering the water with different attitude angles and impact velocities. A particle shifting method is included in the δ+-SPH model to increase accuracy. For determining the ideal particle spacing for this issue, a convergence analysis is done. Based on that, the slamming loads of the capsule ditching at different pitch angles are simulated and explored. Then, a simulation of the Titan capsule ditching is performed, and the results are compared to the experimental data. It is verified that large inclination angles and vertical velocities of the capsule tend to cause overturning, which should be carefully considered and avoided in the engineering design. Finally, the ditching of a capsule on Titan's hydrocarbon lake is also simulated.