Cibrian, R. | Search NASA

NASA NTRS1974

Non-equilibrium stagnation region aerodynamic heating of hypersonic glide vehicles

A simple method of predicting aerodynamic heating and corresponding radiation equilibrium surface temperature-time histories for critical locations on space shuttle orbiter-type vehicles is presented. The method is based on a generalization of correlation equations developed earlier by Rosner for predicting the energy transfer and radiation equilibrium temperatures of surfaces with arbitrary catalytic activity and total hemispheric emittance. Recently obtained experimental data for O and N atom recombination probabilities on candidate material surfaces above 1000 K are used to assess nonequilibrium effects for a range of nose radii and a specific space shuttle re-entry trajectory. It is concluded that low catalytic activity will be especially important in locations of large effective nose radii by both increasing oxidation-resistant coating lifetime and reducing energy transfer into the vehicle.

Rosner, D. E.↗

NASA NTRS1973

Catalysis study for space shuttle vehicle thermal protection systems

Experimental results on the problem of reducing aerodynamic heating on space shuttle orbiter surfaces are presented. Data include: (1) development of a laboratory flow reactor technique for measuring gamma sub O and gamma sub N on candidate materials at surfaces, T sub w, in the nominal range 1000 to 2000, (2) measurements of gamma sub O and gamma sub N above 1000 K for both the glass coating of a reusable surface insulation material and the siliconized surface of a reinforced pyrolyzed plastic material, (3) measurement of the ablation behavior of the coated RPP material at T sub w is greater than or equal to 2150 K, (4) X-ray photoelectron spectral studies of the chemical constituents on these surfaces before and after dissociated gas exposure, (5) scanning electron micrograph examination of as-received and reacted specimens, and (6) development and exploitation of a method of predicting the aerodynamic heating consquences of these gamma sub O(T sub w) and gamma sub N(T sub w) measurements for critical locations on a radiation cooled orbiter vehicle.

Breen, J.↗