Brazilian VLM - Atmospheric stage separation analysis

The Brazilian Microsatellite Launch Vehicle (VLM) is a three-stage launcher, whose motor cases for first and second stages are manufactured by using filament-winding technique (carbon fiber). This vehicle is under development in the Institute of Aeronautics and Space - Brazil. In this project, the staging of the first stage during the atmospheric phase of fight (about 25km) is a critical issue that plays an important role of interest. At this altitude, the VLM is still under effect of non-negligible aerodynamic loads and, in the case of cold separation, the loss of control or re-contact between jettisoned part and the main body of the vehicle can occur. In the last years, methods based on CFD has been applied in the stage separation analyzes. However, these methods present high computational cost and consume a lot of time to process sensibility analyzes or Monte Carlo method due high number of cases to process. As a consequence of the problems addressed before, the main purpose of this paper is to discuss, model and analyze the atmospheric staging of the VLM considering hot separation and uncertainties and variations in the vehicle mass properties, inertia matrix, thrust rise time and TVC deviation. In order to achieve the purpose of this study, it is developed a 6-DoF mathematical model to simulate two body interactions during a hot separation process, by using a modified analytical technique for predicting the plume impingement force during tandem stage separation, including the reversed flow effects. Preliminary studies have shown good results in absence of uncertainties. By applying this new approach it is expected a fast and reliable methodology for hot separation analyzes

Atmospheric re-entry stability analysis of the space vehicle SARA

The aim of this paper is to present a re-entry stability analysis for the uncontrolled, non-winged, blunted cone space vehicle SARA (Atmospheric Re-entry Satellite) by taking into account a ballistic trajectory. The SARA project is a cooperation between Brazilian Space Agency (AEB) and Institute of Aeronautics and Space (IAE) to develop and construct a recoverable space vehicle to perform microgravity experiments. The Brazilian suborbital rocket VS-40 provides the insertion of the SARA capsule into microgravity environment reaching altitudes above 190 km. The analyzes presented in this work focuses on two configurations for SARA being the first, a blunted cone without aps (aero-breaking) and, the second, a blunted cone with aps. The work shows in details the re-entry stability analysis and co-simulation methodology including Newton's impact method modeling (NIM) and Computational Fluid Dynamics (CFD) software