There two main challenges for hypersonic weapons and vehicles are for engines and rockets to generate the speed and for materials that can survive at the extreme temperatures. Moving at hypersonic speeds of 5 to 25 or more times the speed of sound in the atmosphere generates extremely high temperatures.
There are some carbon-based composite materials that are currently used. Composites composed principally of C-C with coatings are able to be used higher temperature operation. There are approaches that rely principally on ablation as a thermal management method and techniques for enhancing heat transfer solely through solid conduction. Increasing heat conduction allows materials to get rid of the extra heat.
DARPA’s MACH program is a four year, two-phase effort.
The first goal is to develop fully integrated leading-edge solutions that can be put into near-term hypersonic platforms.
The second goal will explore new materials spaces such as new metal alloys, ceramic compositions, or robust coatings that can withstand 2200 degrees Celsius under oxidative conditions. DARPA will also look at new ways to achieve extreme cooling. They are looking at over 1500 Watts per square centimeter of cooling.
Success with this program could result in improved materials for next-generation SpaceX reusable rockets.
Having materials able to withstand higher temperatures will enable more efficient and aerodynamic vehicles to be created. Current materials are blunt and not aerodynamic. Current materials are able to withstand the high temperatures but get damaged which requires costly maintenance for systems that are used many times.