GALILEO PROBE HEAT SHIELD ABLATION EXPERIMENT

The Galileo Probe deceleration module contained an experiment that mea sured the surface recession of the forebody heat shield during the hyp ersonic entry into the Jovian atmosphere. A detailed description of th e experiment, reduction of the recession data, reconstruction of the h eat-shield shape history, and comparisons with preflight predictions a re presented. Sensor performance was compromised by an extraneous sign al during the first half of the hypersonic entry, but data quality was reasonably good for the second half of the entry. To within measureme nt accuracy the ablation was axisymmetric, and the final shape was wel l defined. Stagnation point recession was significantly less than pred icted. Frustum recession exceeded predictions and was comparable to st agnation point recession.