Hypersonic Technology Vehicle 2 (HTV-2) is an experimental hypersonic glide vehicle developed as part of the DARPA Falcon Project designed to fly in the Mach 20 range. It is a test bed for technologies to provide the United States with the capability to reach any target in the world within one hour (Prompt Global Strike) using an unmanned hypersonic bomber aircraft. 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. Both these missions are funded by the US Defense Advanced Research Projects Agency (DARPA) to help develop hypersonic technologies and to demonstrate its effectiveness. Under the original plan, HTV-1 was to feature a hypersonic lift-to-drag ratio of 2.5, increasing to 3.5-4 for the HTV-2 and 4-5 for the HTV-3. The actual lift-to-drag ratio of HTV-2 was estimated to be 2.6. HTV-2 was to lead to the development of an HTV-3X vehicle, known as Blackswift, which would have formed the basis for deployment around 2025 of a reusable Hypersonic Cruise Vehicle, an unmanned aircraft capable of taking off from a conventional runway with a 5,400 kg (12,000 lb) payload to strike targets 16,650 km away in under 2 hours. The HCV would have required a lift-to-drag ratio of 6-7 at Mach 10 and 130,000 ft (40,000m). Design Development of protection structures that are tough and lightweight, 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. 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 craft could cover , the distance between London and Sydney, in 49 minutes. Built by Lockheed Martin, the HTV-2 is made of carbon composite material; the durability of such material was needed to prevent important internal components from being destroyed because they are a few inches from its surface. The surface temperature of the HTV-2 was expected to reach or more in flight; steel melts at . Flight testing Both flights reached Mach 20 (high-hypersonic speed) and lost telemetry at 9 minutes of a planned 30-minute mission. The HTV-2's first flight was launched on 22 April 2010. The HTV-2 glider was to fly across the Pacific