One of the first major experiments flown on the NASA SR-71 involved a laser air-data sensor

During the 1990s two SR-71 Blackbird aircraft were used by NASA as testbeds for high-speed and high-altitude aeronautical research at Dryden. The aircraft included an SR-71A and SR-71B (the trainer version), loaned to NASA by the U.S. Air Force. Information from the LASRE experiment helped Lockheed Martin maximize its design for a future potential reusable launch vehicle. It gave Lockheed an understanding the performance of the X-33 lifting body and linear aerospike engine combination.

The first of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory was flown in March 1993. 

The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound.