Turbine engine performance, as measured by specific fuel consumption (defined as fuel consumed relative to the thrust produced by the engine), is a key criterion in engine selection. To achieve the specific fuel consumption required of modern engines, engineers combine advanced designs and materials to achieve higher operating temperatures and, therefore, higher engine efficiency. One of the difficulties of using advanced materials is that they exploit scarce, hard-to-replace elements to allow higher operating temperatures. In this article, we describe steps being taken by General Electric Co. and the turbine engine industry to continue to improve engines in a material space constrained by material availability. As a specific example, we focus on the transition metal rhenium.