Numerical Study of the First Stage Reentry Using an Inflatable Ballute

This article investigates the use of inflatable ballutes to decelerate the first stage of a launch vehicle during atmospheric reentry, thereby enabling its recovery and reuse. In recent years, reusable launch vehicles (RLVs) have attracted significant interest because of their potential to substantially reduce the cost of space missions. A prominent example is the Falcon 9 first stage, which has been successfully reused dozens of times. In that case, deceleration during reentry is achieved through retro-propulsion, with the engines reignited to slow down the vehicle. As an alternative braking strategy, this work explores the use of inflatable ballutes. To assess their performance, Computational Fluid Dynamics (CFD) simulations were carried out using a conjugate heat transfer (CHT) approach. This methodology makes it possible to evaluate both the aerodynamic drag and the thermal loads generated by the combined effects of hypersonic flow and engine exhaust gases. The results indicate that inflatable ballutes provide significantly greater deceleration than retro-propulsion alone, thereby reducing the propellant required for recovery. In addition, they can mitigate the thermal loads on the side walls of the reusable stage during descent.