NASA has announced funding to develop a hypersonic fixed wing air/space vehicle capable of flight speeds between Mach 8 and Mach 20. Over five years US$5 million will be spent on the research and development of a vehicle that could one day take the first humans to Mars.
NASA intends to fill technological gaps in the areas of materials and structures, air-breathing propulsion, aerodynamics, aerothermodynamics, plasmadynamics, atmospheric decelerator technologies, and entry descent and landing technologies. Identified as the two primary areas of interest for the funding period are developing an air-breathing propulsion system capable of gaining access to outer space, and designing an entry, descent, and landing (EDL) system for the delivery of high-mass vehicles into planetary atmospheres.
The NASA report (PDF) said this was part of the goal to: “Develop a balanced overall program of science, exploration, and aeronautics consistent with the redirection of the human spaceflight program to focus on exploration.”
The current landing systems used by NASA, including the Mars Science Laboratory due to be launched in 2011, use technology from the 1970's-era Viking lander. The largest restriction faced is a limited payload of about 1.25 Mt. “In order to enable landing the larger payloads that will be required for large-scale science, in-situ resource utilization, and eventual human exploration, a new generation of innovative entry and descent technologies is required,” the report said. “The Hypersonics Project has a goal of developing and maturing fundamental technologies required to build future planetary atmospheric EDL systems that will enable large science missions (2-10 Mt) and human (20-100 Mt) exploration of Mars.”
Another major challenge facing the achievement of hypersonic flight is the severe heating experienced at this speed range (Mach 8 – 20). This not only dictates the development of materials capable of withstanding extremes in temperature, but also significantly influences the shape and controllability of the vehicle.
“Boundary-layer transition and turbulence at hypersonic speeds are especially significant because of the large differences in heating rates between laminar and turbulent flows,” the report said. “The interaction of bow shock and wing shocks and/or inlet shocks (shock-shock interaction) leads to local enhancement of heating at the impingement point. Therefore, the accurate definition and characterization of the hypersonic environment is of paramount importance, placing great emphasis on computational tools and high-enthalpy experimental measurement capabilities. The hypersonic heating environment, coupled with the emphasis on reusability, creates additional severe technology challenges for materials, material coatings, and structures that not only carry the aerodynamic loads of the air but also repeatedly sustain high thermal loads.”
All of this R&D points to one thing: NASA's new commitment to rekindling the human exploration of our solar system starting with Mars.