Mars Pathfinder entry temperature data, aerothermal heating, and heatshield material response

The Mars Pathe nder probe contained instrumentation that measured heatshield temperatures during entry. A description of the experiment, the data, and an analysis of the entry environment and material response are presented. Navier ‐Stokes forebody heating calculations show a peak unblown radiative-equilibrium heat e ux of 118W/cm 2 at thestagnation point and120 W /cm 2 on theshoulderforturbulente ow. Theheatload is3.8 kJ /cm 2 on thenose,decreases along thefrustum,then increasesto 2.7 ‐3.1kJ/cm 2 on theshoulder depending on the onset time forturbulence. One-dimensional charringmaterialresponseiscalculated using threedifferentmodels.Stagnationpoint temperature data are consistent with about 85% of fully catalytic laminar heating. Shoulder temperature data are inconclusive, but are consistent with fully catalytic laminar heating or with 85% of fully catalytic heating with early onset of turbulence. Aft temperature data indicate a peak heat e ux and heat load of about 1.3 W /cm2 and 70 J/cm 2 , respectively. The aft heating proe le is about 20 s longer than the forebody heating proe le. Bondline temperaturedata, although not useful forquantitative analysis of aerothermal heating, clearly showtheheatshield had adequate thickness margins for the actual entry.

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