Mach 6

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In this Jan. 31, 2019, image provided by the U.S. Air Force Academy, Cadet 2nd Class Eric Hembling uses a Ludwieg Tube to measure the pressures, temperatures, and flow field of various basic geometric and hypersonic research vehicles at Mach 6 in The United States Air Force Academy's Department of Aeronautics, in Colorado Springs, Colo. (Joshua Armstrong/U.S. Air Force Academy via AP) **FILE**