Particle simulation of rarefied aeropass maneuvers of the Magellan spacecraft
Abstract
Rarefied and free molecular flowfields corresponding to proposed aeropass maneuvers through the atmosphere of Venus by the Magellan spacecraft are computed with a vectorized particle simulation method. The significance of rarefaction and reaction effects are assessed and surface heat flux, drag coefficients, and flowfield properties are computed. A simple surface heat transfer model is coupled directly to the simulation and assumes that each surface element is in radiative equilibrium with deep space. This allows direct computation of surface temperature distributions rather than requiring prescribed isothermal boundary conditions. Uncoupled dualnode heat transfer models, which account for heat capacity and thermal conductivity within each structural component, permit more accurate determination of surface temperatures. Such temperatures restrict the allowable altitudes and entry speeds of the aeropass maneuvers, and must therefore be estimated accurately. Simulations with an entry velocity of 8600 m/s at altitudes between 125 and 140 km reveal that allowable surface temperatures occur only at the highest altitudes where the flowfield is appropriately modeled as freemolecular. Excessive surface heat flux occurs at lower altitudes where molecular collisions are significant.
 Publication:

AIAA, 27th Thermophysics Conference
 Pub Date:
 July 1992
 Bibcode:
 1992thph.confW....H
 Keywords:

 Aerobraking;
 Flow Distribution;
 Free Molecular Flow;
 Heat Flux;
 Magellan Spacecraft (Nasa);
 Rarefaction;
 Elliptical Orbits;
 Heat Transfer;
 Surface Temperature;
 Temperature Distribution;
 Fluid Mechanics and Heat Transfer