Low-Cost Refractory Metal-Lined Graphite and Carbon/Carbon Components for Advanced SDACS and LDACS, Phase II

Rhenium hot gas path components are used extensively in the solid divert and attitude control system (SDACS) of the Standard Missile-3 (SM-3) Block 1A Aegis ballistic missile defense system, on which Ultramet is a key subcontractor. The mechanical, thermal, and chemical performance of rhenium is unmatched. However, a need exists to reduce the cost and weight of rhenium-based structures for advanced DACS. In previous and current work, Ultramet has demonstrated the potential of fabricating rhenium-lined low-density graphite and carbon/carbon components, in combination with a carbon diffusion barrier interlayer to prevent loss of rhenium ductility and damage to the carbon-based support structure. This combination of materials will allow the benefits of flight-qualified rhenium to be retained at substantially reduced weight and cost. Rhenium offers high toughness and thermal and mechanical shock resistance that ceramic coatings cannot provide, as well as gas impermeability that cannot be achieved with ceramic matrix composites. In Phase I, Ultramet demonstrated the initial feasibility of a rhenium-lined graphite poppet for a long-duration hot gas valve being developed by Valley Tech Systems for Aerojet"s SM-3 Block 2B SDACS. In Phase II, application of the technology will be expanded beyond SDACS valve components to also include thrusters for Aerojet"s SM-3 Block 2B liquid DACS (LDACS). LDACS will require rhenium thrusters that are lined with iridium, and Ultramet is the only manufacturer of flight-qualified and proven iridium/rhenium thrusters. Design and analysis will take advantage of Ultramet"s extensive experience in manufacturing flight components from rhenium for SM-3 Block 1A and from iridium/rhenium for commercial satellite liquid propulsion systems. Performance will be established through hot-fire testing at Valley Tech Systems and Aerojet.