Hypersonic propulsion offers the potential for future space access to Low Earth Orbit (LEO) that is safer, more reliable and more affordable than today’s rocket technologies. The U.S. space program is facing a growing challenge to its global leadership position. Current launch costs are staggering and unless reduced, these costs will continue to consume valuable resources and reduce potential achievements in science, exploration, and commercial development. As an agency, NASA has been working towards the development of safe, inexpensive space access platforms to enable the U.S. commercial sector to flourish in space endeavors. In response to this challenge, the Next Generation Launch Technologies (NGLT) Program is providing development of technologies to meet the 3rd generation RLV goals which strive to increase safety by four orders of magnitude and reduce costs by two orders of magnitude within 25 years.

Present studies indicate that the most efficient concept for hypersonic space access is a Two- Stage-To-Orbit (TSTO) vehicle powered by a turbine-based propulsion system. Use of turbine-based propulsion provides the potential to realize more aircraft-like operations for space flight thereby providing the potential to significantly reduce launch costs and improve systems safety. In addition, if aircraft like operations can be realized then the potential to use existing aircraft ground facilities become a realistic opportunity to revolutionize access to space scenarios.

Light weight, high temperature materials are enabling technologies for both propulsion systems and airframes. The most promising are the gamma-based titanium aluminides which are being book kept for structural components in scramjets and turbine accelerators as well as control surfaces on hypersonic vehicles. This presentation will address technical challenges for gamma titanium aluminides in hypersonic vehicles including propulsion system requirements.