Speaker
Description
Risk assessment of uncontrolled debris re-entering the atmosphere depends on various parameters among which drag and heat rates play a major role. However, those parameters cannot be computed with high fidelity methods such as CFD (Computational Fluid Dynamics) within a reasonable time frame for a full earth re-entry. Thus, correlations are usually used in spacecraft demise codes that use the object-oriented paradigm. However, correlations have often been derived in the 60s for non-destructive re-entry. A new methodology to compute drag forces and heat rates for destructive re-entry in the continuum regime, for a large range of geometry is presented. The models are based on CFD computations. The method is applied to complex shape for implementation in the object-oriented code DEBRISK v3. The model is extended to the transitional regime and its accuracy assessed thanks to Direct Simulation Monte Carlo (DSMC) computation. The DSMC code used is presented with its validation. Over 3400 simulations are carried out on 105 geometries in order to compute the random tumbling drag and heat rate in the transitional regime. The simulation setup to obtain reliable DSMC results in an automated way is outlined. Simulation results are compared with an approximation model. For the geometries investigated, parameters can be selected such that the average difference between the approximation model and the DSMC results are below 1% for both drag and heat rate
