The single-seat F-16XL NASA 849, with it's afterburner firing, on a flight for the recent sonic boom research program conducted by the Dryden Flight Research Center, Edwards, California., conducted with an SR-71A, NASA 844. During the missions, the F-16XL probed the shockwaves generated by the SR-71, while at lower altitudes sensors on an F-18 and on a YO-3A, and also on the ground, recorded data from the same shockwave.