AFRL Seeks Data On X-Plane
By Guy Norris 
COLORADO SPRINGS, Colo. - The U.S. Air Force Research Laboratory (AFRL) expects to issue a request for information (RFI) "any day now" to industry for a wide array of structures, systems and control technology that could be used as the basis for a hypersonic, responsive space launch demonstrator.
The RFI is for the follow-on phase to the Future responsive Access to Space Technologies (FAST) program, which focused on several ground experiments aimed at developing baseline technology for the future demonstrator.
Originally dubbed the Operationally Responsive Space (ORS) integrated ground experiment, the new program is expected to be renamed along the lines of the Reusable Booster System Integrated Demonstrator to emphasize the X-plane aims of the effort.
AFRL says the RFI is aimed at "maturing technology in areas such as structures, guidance and control and fault tolerance." The plan will be to demonstrate a high level of integration, culminating in a scaled X-plane vehicle that will show capabilities to technology readiness level 6 (ready for full-scale development) by around the 2017-2018 time frame.
Concept models of the fly-back winged booster and a similar winged booster with a rocket-powered payload module carried piggyback were revealed at the National Space Symposium here. The models bore a strong resemblance to the scaled model booster flight-tested by Lockheed Martin early in 2008. These tests, conducted in New Mexico, were primarily to investigate guidance and control concepts for the two-stage to orbit vehicle, which will be autonomously controlled at speeds of up to Mach 6 for the first-stage and up to Mach 9 and beyond for the second stage.
Technologies explored by the earlier FAST program included an all-composite airframe, load-bearing tanks attached to wing box carry-through and thrust structures, and thermal protection systems with operable seals and mechanical attachments.
Other ground experiments include adaptive guidance and control subsystems with the ability to reshape trajectories on-line and mission replanning in response to subsystem failures. Another aspect of FAST involved development of a laboratory for exploring concepts for operating a quick-turnaround, reusable space launch vehicle, rapid mission planning, in-flight command and control and ground operations.
Booster concept model photo: U.S. Air Force
