Aerodecelerator Performance of Flare-Type Membrane Inflatable Vehicle in Suborbital Reentry

Abstract

A flight experiment of an inflatable reentry vehicle, equipped with a thin-membrane aeroshell deployed by an inflatable torus structure, was performed using a JAXA S-310-41 sounding rocket. The drag coefficient history was evaluated by analyzing the acceleration of the vehicle with atmospheric density and temperature using a global reference atmospheric model. The vehicle successfully demonstrated deceleration. During the reentry flight, the position, velocity, and acceleration of the vehicle were obtained by using the Global Positioning System. The experimental drag coefficient had an almost constant value of 1.5 in the supersonic region but decreased to 1.0 in the subsonic region. In the transonic region, a steep decrease of the drag coefficient was confirmed. To study the detailed aerodynamics for the reentry vehicle, flow-field simulations were conducted with computational fluid dynamics techniques. The aerodynamic force acting on the vehicle was investigated with the measured data throughout the supersonic and subsonic regions. In the flow-field simulation, the computed result for the drag coefficient shows reasonable agreement with the experimental one. In addition, a compressible effect in front of the vehicle was seen to appear in the supersonic region and a vortex ring at the rear of the vehicle was formed in the subsonic region.

Drag Behavior of Inflatable Reentry Vehicle in Transonic Regime

“…Turbulence in the wake is enhanced for a larger scale model case and leads to high pressure behind the test model. This is also confirmed in the CFD results for the SMAAC flight test [25].…”

Aerodynamic instability of an inflatable aeroshell in suborbital re-entry

“…Additionally, membrane deformation was not considered in this study. The effects on deformation were minor for aerodynamic deceleration, as reported by Takahashi et al 37 However, deformation possibly had a significant effect on the pitching moment behavior owing to formation change. In particular, as the computed results indicated, deformation could become important for the phase delay of front pressure.…”

Aerodynamic instability of flare-type membrane inflatable vehicle in suborbital reentry demonstration

“…Thus far, various aerodynamic studies have been conducted on SMAAC. Ha et al (Ha et al, 2014a) and Takahashi et al (Takahashi et al, 2017) investigated aerodynamic characteristics of SMAAC with a computational fluid dynamics (CFD) approach, for various cases between altitude of 58 km and 1.0 km, i.e., from a supersonic flow regime to a subsonic one. In the paper, the simulated drag coefficient showed good agreement with the measured results.…”