Suborbital reentry demonstration of inflatable flare-type thin-membrane aeroshell using a sounding rocket

An inflatable decelerator is promising as a next-generation atmospheric-entry system owing to its reduced aerodynamic heating and high packing efficiency. In this study, a suborbital reentry demonstration of a flare-type thin-membrane aeroshell sustainedby asingle inflatable torus using an S-310-41 sounding rocket was carried out. An experimental vehicle was specially developed for this reentry demonstration; itwas equipped witha1.2-m-diam flare-type thin-membrane aeroshell and had a total mass of 15.6 kg. In the flight test, the aeroshell with an inflatable torus was deployedatanaltitude of 100 kmduring asuborbital flight under the conditionsofzero-gravity and near vacuum. The experimental vehicle reentered Earth's atmosphere fromanaltitude of 150 km. During free fall, it accelerated toa Mach number of 4.5 (1.32 km/s) because of gravity force. After that, it started decelerating because of aerodynamic force at an altitude of 70 km. According to the flight data, the vehicle remained intact during the reentry and the aeroshellachieved the expected decelerating performance. This reentry demonstration proves that the flare-type thin-membrane aeroshell sustained by the inflatable torus works well as a decelerator for atmospheric-entry vehicles. Further, the drag coefficient of the experimental vehicleinthe supersonic, transonic, and subsonic regimes under free-flight conditions was estimated from the flight trajectory.