Materials for Next-Generation Rocket Engines

Iridium/Rhenium (Ir/Re) technology developed at Ultramet has demonstrated the ability of liquid rocket engines to operate above 2200C for tens of hours. 22-N (5-lbf) and 445-N (100-lbf) units have been built and tested, and have demonstrated an improvement in specific impulse (Isp) of some 20 seconds, which translates into a productivity increase of 5-10%. Similar results could be achieved if this technology could be transferred to large and/or new technology engines, such as electric propulsion. The key problem is weight, as the structural material, rhenium, has a density of 21 g/cm3 and 44.5-kN (10,000-lbf) engine made of solid rhenium would weigh some 200 kg, which is unacceptably high. In this Phase I program, Ultramet proposes to demonstrate the feasibility of fabricating large Ir/Re rocket engines that exhibit the same performance as the previously demonstrated small engines but with no weight penalty, through the application of bold and innovative materials science to the develpment of unique composite structures such that further advances can be made in this area of technology.