Ultramet will design and fabricate a lightweight, high temperature 5-lbf combustion chamber. The system will be designed for use with the AF-315 family of monopropellants, which have specific impulse values well in excess of 240 sec, and the combustion chamber material will be based on Ultramet's proven [Zr,Si]C ceramic matrix composite (CMC) technology. This material system allows the zirconium carbide to silicon carbide ratio in the matrix to be adjusted, thus enabling the material to be optimized for different combustion environments. To date, hot-fire testing has been done on Ultramet CMC chambers with both O2/H2 and AF-315e propellants. Ultramet will work closely with a leading supplier of spacecraft propulsion systems that will provide the chamber design and perform the hot-fire testing. The fabrication process and the survivability of the material system will be demonstrated in Phase I. Phase II would include long-duration life testing of the Phase I chamber as well as the design, fabrication, and testing of a chamber in the 100- to 500-lbf thrust class suitable for a payload ascent vehicle.