Today DARPA will launch the second HTV2 that explores the 20mach region. It is launched aboard a Minotaur IV rocket and after re-entering Earth's atmosphere it glides until its destruction. At this altitude 20 mach translates to 13.000mph and DARPA states that the control system is one of the three key technical areas of the program (along with aerodynamics and heat management). The first flight was in April and after 9min communication was lost.
You can follow the launch live from @DARPA_News on twitter with the tag #HTV2
The video above shows a simulation of the complete flight (via robotpig.net )