A material that behaves likes a glassy ablator on the surface, has a low thermal conductivity, is structurally tough, lightweight, and is in some sense reusable, would be desirable for the protective heat shield used on Earth entry vehicles. A material for this purpose has been developed that uses silicon dioxide (fused quartz) in a fibrous packed matrix, forming blocks which can behave as a glassy ablator on the surface when subject to very high surface heat fluxes. These fibrous silicon dioxide blocks are called Reusable Surface Insulation (RSI). The primary constituent of the RSI material is silicon dioxide, but may contain other compounds (e.g. alumina borosilicate) to affect the thermal and physical properties. The research performed in this thesis is to determine the ablative behavior of ceramic RSI materials in a hypersonic high enthalpy flow that is used to simulate entry into Earth atmosphere. Actual arc jet experiments were performed to measure mass loss, melt run off, and fiber collapse of these materials and compare the experimental results with predicted theoretical values. The tests were performed to ascertain if RSI type materials could be used for entry vehicles proposed in NASA Mars missions.

Subjects: Space vehicles; Atmospheric entry; Mars (Planet); Ablative materials; Shielding (Heat); Ablative; hypersonic; NASA; Mars; heat shield