Abstract
Japan Aerospace Exploration Agency has a plan to develop the HTV-R which is an extended version of the HTV. The HTY-R will be a spacecraft for developing a re-entry capsule similar to the Apollo spacecraft. The recovery on the sea surface is the promising methods to develop a Japanese capsule, therefore the shock mitigation at splashdown is one of the key technologies. In the present study, preliminary splashdown tests using a 6.8 percent scale model of the re-entry capsule were performed in the required three kinds of splashdown velocities and four kinds of initial attitude angles of the model. A measuring system of acceleration was constructed, which recorded time histories of acceleration and sent the data to PC wirelessly and measured its splashdown behaviors using five accelerometers. Experimental data obtained from five accelerometers are evaluated based on water impact theory that is considered from virtual mass and conservation of momentum. It was made clear that the maximum acceleration at splashdown was obviously mitigated in the case of initial attitude angle 30 degree compared to other initial attitude angles.
