Crew safety evaluation and injury mechanism at Launch Abort System based on multibody simulation

Abstract

Human space flight vehicle requests a high safety level to protect life of astronauts. Launch Abort System (LAS) is a safety system used to quickly separate the space capsule from its launch vehicle rocket in case of catastrophic failure such as explosion of the vehicle. During the launch abort, the blast wave from explosion or off-nominal water landing causes severe transient load on the space capsule, so that the crew might be injured by huge acceleration. In order to evaluate LAS safety, simulation based injury assessment is essential in the basic design phase. This paper purposes to develop a numerical model based on the multi-body simulation approach, which is widely used for analyzing car occupant safety. In this paper, simulation of impact sled tests is conducted to measure human dummy responses and loads. The results are compared with the Hybrid III dummy sled test data to investigate accuracy of this multi-body simulation. It shows that the computed results agree well with the test data. Finally, an injury analysis of crew members subjected to an expected acceleration load during the launch abort is investigated by using the validated model. The results show that a head or neck injury is more likely to happen during the launch abort. The mechanism of the human response is also discussed and the study provides guidelines for seat designs in space vehicle.