Hypersonic Technology Vehicle HTV-2 reentry (artist's impression)
Hypersonic Technology Vehicle 2 (HTV-2) is a crewless,
[1] experimental
rocket glider developed as part of the
DARPA Falcon Project capable of flying at 13,000 mph (21,000 km/h).
[2] It is testing technologies to provide the
United States with the capability to strike any target in the world within one hour.
[3]
Development
The Falcon HTV-1 program, which preceded the Falcon HTV-2 program,
was conducted in April, 2010. The mission ended within nine minutes from
launch.
[3] Both these missions are funded by the US Defense Advanced Research Projects Agency (DARPA) to help develop
hypersonic technologies and to demonstrate its effectiveness.
[4]
Design
DARPA's Falcon Hypersonic Technology Vehicle-2
Development of protection structures that are tough and light-weight,
development of an aerodynamic shape that has a high lift to drag ratio,
development of automatic navigation control systems etc. were some of
the initial technical challenges that had been overcome in the final
design.
[4]
The various departments involved in designing the vehicle included
aerothermodynamics, materials science, hypersonic navigation, guidance
and control systems, endo- and exo-atmospheric flight dynamics,
telemetry and range safety analysis. The
Sydney Morning Herald
notes that when flying its fastest, the craft could cover 17,000
kilometres, the distance between London and Sydney, in 49 minutes.
[3]
Flight testing
Launch of HTV-2a on a Minotaur IV Lite rocket
Falcon HTV-2 baseline flight test trajectories
The HTV-2's first flight was launched on 22 April 2010.
[5] The HTV-2 glider was to fly 4,800 miles (7,700 km) across the
Pacific to
Kwajalein at Mach 20.
[6] The HTV-2 was boosted by a
Minotaur IV Lite rocket launched from
Vandenberg Air Force Base,
California. The flight plan called for the craft to separate from the
launch vehicle, level out, and glide above the Pacific at Mach 20.
[1][3] Contact had been lost with the vehicle nine minutes into the 30-minute mission.
[3][7][8]
In mid-November DARPA stated that the first test flight had ended when
the computer autopilot had "commanded flight termination" after it had
begun to roll violently.
[9]
A second flight was initially scheduled to be launched on August 10, 2011, but bad weather forced a delay.
[10]
The flight was launched the following day, on 11 August 2011. The
unmanned Falcon HTV-2 successfully separated from the booster and
entered the mission's glide phase, but again lost contact with control
about nine minutes into its planned 30-minute Mach 20 glide flight.
Initial reports indicated it purposely impacted the Pacific Ocean along
its planned flight path as a safety precaution.
[11][12][13]
Future
Darpa does not plan to conduct a third flight test of the HTV-2. The
decision was because substantial data was collected from the first two
flights, and a third was not thought to provide any additional valuable
data for the cost. The first flight provided data in aerodynamics and
flight performance, while the second provided about structures and
high-temperatures. Experience gained from the HTV-2 will be used to
perfect hypersonic flight. Work on the HTV-2 will continue to summer
2014 to capture technology lessons and improve design tools and methods
for high-temperature composite aeroshells.
[14]
See also
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