We have talked about the DARPA HTV-2 hypersonic glider that has been in testing before. The goal of the program is to be able to create a weapon that can strike anywhere on the planet within a few hours. The first test flight resulted in the loss of the HTV-2 about nine minutes into the flight and the aircraft was never found. The second test flight failed in the same phase of the flight. The second failure was further into the flight and was caused by different issues than the first flight failure according to DARPA.
DARPA reportedly had 22 different stations along the flight path of the HTV-2 to collect data on the flight and oddly, when the flight was lost the only video came from a handheld camcorder used on the deck of one of the monitoring vessels by a crewmember. The video you can see below shows the aircraft as the third stage booster releases the craft.
According to DARPA, the flight was stable and controlled at Mach 20 for three minutes before the anomaly occurred. That is longer than the length of the flight the first craft accomplished. The changes made to the HTV-2 after the first failed flight were effective and the failure this time was due to other causes. Check out the video of the HTV-2 below along with a second video comparing the speed of the HTV-2 to other aircraft.