This after the HTV-2 being launched atop a Minotaur IV Lite rocket from Vandenberg Air Force Base in California to test out DARPA’s ability to control a vehicle moving at speeds higher than Mach 5 or Hypersonic as the Americans call it. HTV-2 intended splashdown in The Pacific Ocean near Kwajalein Atoll, some four thousand miles (4,000 miles) or six thousand six hundred and sixty seven (6667 km) downrange from Vandenberg Air Force Base.
Apparently this target was missed, as since then DARPA has yet to make any declaration as to having broken Air Force's X-51A WaveRider record of two hundred (200) seconds of autonomous flight at the Hypersonic Speed of Mach 5 (6100 km/hr or 3675 mph) using a SCRAMJet (SuperSonic Combustion Ramjet) as stated in the article “X-51A races to hypersonic record”, published MAY 26, 2010 8:33 PM PDT By Jonathan E. Skillings, CNET News - MILITARY TECH.
This as Mach 20, the intended speed of the HTV-2 , is 11440 km/hr faster than the speed of an electron in a vacuum, making Relativity….well, relevant! Or finding the Test Vehicle for that matter after it's lost from visible or Radio horizons, Moonraker (1979) or Hunt for Red October (1990) Style.