Analysis of Rocket Lab’s Electron re-entry with a hypersonic inflatable aerodynamic decelerator (Ballute)

Abstract

Currently, Rocket Lab attempts to recover the first stage of their Electron rocket by direct atmospheric re-entry and subsequent use of a drogue and primary parachute. Exposing the rocket to high decelerations during re-entry leads to equally high mechanical and thermal stresses on the rocket itself. These can only be endured if the stage acts like a blunt body and pushes the shockwave in front of the vehicle in order to avoid shockshock interactions. This study investigates a hypersonic inflatable aerodynamic decelerator in form of a trailing isotensoid or ballute. These can greatly reduce the peak stresses on the rocket by enabling significant deceleration in the higher atmosphere. Furthermore, it is possible to release them again after a deceleration limit is achieved and the subsequent free-falling rocket does not exceed predefined thermal boundaries anymore. This must be investigated in a detailed system study.