主题：美国一日双射亚轨道高超音速无人机、X-37B太空战机！ -- 尖石

By Janene Scully/Associate Editor A military experiment of hypersonic technology apparently ended in failure shortly after a Minotaur 4-Lite launched Thursday afternoon from Vandenberg Air Force Base, officials said late Friday.

The Defense Advanced Research Projects Agency launched its Falcon Hypersonic Technology Vehicle 2 at 4 p.m. Thursday from South Base.

In the statement released Friday night, DARPA said preliminary review of technical data reveals that the rocket “successfully delivered the HTV-2 glide vehicle to the desired separation conditions.”

“The launch vehicle executed first-of-its-kind energy management maneuvers, clamshell payload fairing release and HTV-2 deployment,” the DARPA statement said. “Approximately 9 minutes into the mission, telemetry assets experienced a loss of signal from the HTV-2. An engineering team is reviewing available data to understand this event.”

HTV-2 is an unmanned maneuverable hypersonic air vehicle designed to glide through Earth’s atmosphere “at incredibly fast speeds — Mach 20 and above,” DARPA said. Something traveling at Mach 1 is moving at the speed of sound.

Specifically, HTV-2 was to use an autopilot system to maneuver during the hypersonic glider portion of the flight. DARPA planned three maneuvers — turn at moderate angles “to bleed off” excess energy; short pitch, roll and yaw moves; and a dive into the ocean at more than 13,000 mph.

This was the first of two HTV missions, with the second planned for 2011. However, that mission depends upon the outcome of the HTV-2 test, DARPA officials said prior to the launch. The two missions cost about $308 million, DARPA said.

Thursday’s blastoff marked the debut of the Minotaur 4, although it was the “light” version — using just three stages from retired Peacekeeper missiles.