NASA's highly modified F-15, being used for digital electronic flight and engine control systems research, is seen here on a flight from the Dryden Flight Research Facility, Edwards, California. NASA's F-15B aircraft is being used by Dryden as an aerospace research aircraft. Certain experiments can be placed on a Flight Test Fixture, which is mounted under the fuselage. The research projects can then be subjected to different aerodynamic loads, speeds and temperatures. The F-15B, No. 836, was acquired in 1993 and is also used at Dryden as a research support aircraft.