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. [1] [2] [3] [4] 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 (Conventional Prompt Strike) using an unmanned hypersonic bomber aircraft. [5]
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. [5] Both these missions are funded by the US Defense Advanced Research Projects Agency (DARPA) to help develop hypersonic technologies and to demonstrate its effectiveness. [6] 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. [7]
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). [8]
HTV-2 was expected to demonstrate controllable flight at velocities of around Mach 20, i.e., a capability that can reach anywhere in the world in less than an hour. [9] At that speed, the flight time between New York City and Los Angeles would be less than 12 minutes. [9]
Development of protection structures that are tough and lightweight; an aerodynamic shape that has a high lift to drag ratio; automatic navigation control systems were among the initial technical challenges facing the designers. [6] 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 17,000 kilometres (11,000 mi), the distance between London and Sydney, in 49 minutes. [5]
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 1,930 °C (3,500 °F) or more in flight; steel melts at 1,370 °C (2,500 °F). [10]
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. [11] The HTV-2 glider was to fly 4,800 miles (7,700 km) across the Pacific to Kwajalein at Mach 20. [12] The HTV-2 was boosted by a Minotaur IV Lite rocket launched from Vandenberg Air Force Base, California; the glider was carried inside the nose of the Minotaur IV Lite rocket into outer space with a launch altitude of 100 miles (160 km). The flight plan called for the craft to separate from the launch vehicle, level out and glide above the Pacific at Mach 20. [3] [5] Contact was lost with the vehicle at nine minutes into the 30-minute mission, and the glider's skin disintegrated. [5] [13] [14] In mid-November, DARPA stated that the first test flight ended when the computer autopilot "commanded flight termination" after the vehicle began to roll violently. [15]
A second flight was initially scheduled to be launched on August 10, 2011, but bad weather forced a delay. [16] 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. [17] [18] [19] The glider's surface reached 1,930 °C (3,500 °F) (the speed and heat caused part of the skin to peel away from the aerostructure [10] ) and controlled itself for 3 minutes before crashing. [20]
DARPA does not plan to conduct a third flight test of the HTV-2.[ citation needed ] The decision was made because substantial data was collected from the first two flights, and a third was not thought likely to provide any additional valuable data for the cost. The first flight provided data in aerodynamics and flight performance, while the second provided information about structures and high temperatures. Experience gained from the HTV-2 will be used to improve hypersonic flight.
A scramjet is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow. As in ramjets, a scramjet relies on high vehicle speed to compress the incoming air forcefully before combustion, but where as a ramjet decelerates the air to subsonic velocities before combustion using shock cones, a scramjet has no shock cone and slows the airflow using shockwaves produced by its ignition source in place of a shock cone. This allows the scramjet to operate efficiently at extremely high speeds.
The NASA X-43 was an experimental unmanned hypersonic aircraft with multiple planned scale variations meant to test various aspects of hypersonic flight. It was part of the X-plane series and specifically of NASA's Hyper-X program developed in the late 1990s. It set several airspeed records for jet aircraft. The X-43 is the fastest jet-powered aircraft on record at approximately Mach 9.6.
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The Minotaur is a family of United States solid fuel launch vehicles derived from converted Minuteman and Peacekeeper intercontinental ballistic missiles (ICBM). They are built by Northrop Grumman via contract with the Space Force's Space Systems Command as part of the Space Force's Rocket Systems Launch Program (RSLP) which converts retired Intercontinental Ballistic Missiles into space and test launch systems for U.S. government agencies.
The DARPA FALCON Project was a two-part joint project between the Defense Advanced Research Projects Agency (DARPA) and the United States Air Force (USAF) and is part of Prompt Global Strike. The first part of the project aimed to develop a Small Launch System (SLS) capable of accelerating hypersonic gliding weapons as well as launching small satellites into Earth orbit. The second part of the project aimed to develop Hypersonic Weapon Systems (HWS): a short term high performance hypersonic gliding weapon previously named the X-41 Common Aero Vehicle (CAV) that could be launched from Expendable Launch Vehicles (ELV), Reusable Launch Vehicles (RLVs), Hypersonic Cruise Vehicles (HCV), or Space Maneuvering Vehicles (SMP), and a long term hypersonic cruise aircraft named the Hypersonic Cruise Vehicle (HCV). This two-part program was announced in 2003 and continued into 2006.
The Boeing X-51 Waverider is an unmanned research scramjet experimental aircraft for hypersonic flight at Mach 5 and an altitude of 70,000 feet (21,000 m). The aircraft was designated X-51 in 2005. It completed its first powered hypersonic flight on 26 May 2010. After two unsuccessful test flights, the X-51 completed a flight of over six minutes and reached speeds of over Mach 5 for 210 seconds on 1 May 2013 for the longest duration powered hypersonic flight.
Scramjet programs refers to research and testing programs for the development of supersonic combustion ramjets, known as scramjets. This list provides a short overview of national and international collaborations, and civilian and military programs. The USA, Russia, India, and China (2014), have succeeded at developing scramjet technologies.
Lockheed L-301 was an experimental air-breathing hypersonic aircraft project. It was developed by the NASA and United States Air Force (USAF) organization National Hypersonic Flight Research Facility, with Skunk Works as the prime contractor. In January 1977, the program was "tentatively scheduled to operate two vehicles for eight years and to conduct 100 flights per vehicle." NASA discontinued work on L-301 and NHRF in September 1977 due to budget constraints and lack of need.
Hypersonic flight is flight through the atmosphere below altitudes of about 90 km (56 mi) at speeds greater than Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. Speeds over Mach 25 have been achieved below the thermosphere as of 2020.
Minotaur IV, also known as Peacekeeper SLV and OSP-2 PK is an active expendable launch system derived from the LGM-118 Peacekeeper ICBM. It is operated by Northrop Grumman Space Systems, and made its maiden flight on 22 April 2010, carrying the HTV-2a Hypersonic Test Vehicle. The first orbital launch occurred on 26 September 2010 with the SBSS satellite for the United States Air Force.
USA-212 was the first flight of the Boeing X-37B Orbital Test Vehicle 1, an American robotic vertical-takeoff, horizontal-landing (VTHL) spaceplane. It was launched aboard an Atlas V rocket from Cape Canaveral on 22 April 2010, and operated in low Earth orbit. Its designation is part of the USA series.
Conventional Prompt Strike (CPS), formerly called Prompt Global Strike (PGS), is a United States military effort to develop a system that can deliver a precision-guided conventional weapon strike anywhere in the world within one hour, in a similar manner to a nuclear ICBM. Such a weapon would allow the United States to respond far more swiftly to rapidly emerging threats than is possible with conventional forces. A CPS system could also be useful during a nuclear conflict, potentially replacing the use of nuclear weapons against up to 30% of targets. The CPS program encompasses numerous established and emerging technologies, including conventional surface-launched missiles and air- and submarine-launched hypersonic missiles, although no specific CPS system has yet been finalized as of 2018.
The Alpha Draco missile, also known as Weapons System 199D (WS-199D), was an experimental ballistic missile developed by McDonnell Aircraft in the late 1950s to investigate the aerodynamic physics of the boost-glide reentry trajectory. Three test flights were conducted in 1959, of which two were successful.
The DARPA XS-1 was an experimental spaceplane/booster with the planned capability to deliver small satellites into orbit for the U.S. Military. It was reported to be designed to be reusable as frequently as once a day, with a stated goal of doing so for 10 days straight. The XS-1 was intended to directly replace the first stage of a multistage rocket by taking off vertically and flying to hypersonic speed and high suborbital altitude, enabling one or more expendable upper stages to separate and deploy a payload into low Earth orbit. The XS-1 would then return to Earth, where it could ostensibly be serviced fast enough to repeat the process at least once every 24 hours.
The Lockheed Martin SR-72, colloquially referred to as "Son of Blackbird", is an American hypersonic UAV concept intended for intelligence, surveillance and reconnaissance (ISR) proposed privately in 2013 by Lockheed Martin as a successor to the retired Lockheed SR-71 Blackbird. In 2018, company executives said an SR-72 test vehicle could fly by 2025 and enter service in the 2030s.
Non-ballistic atmospheric entry is a class of atmospheric entry trajectories that follow a non-ballistic trajectory by employing aerodynamic lift in the high upper atmosphere. It includes trajectories such as skip and glide.
The Avangard is a Russian hypersonic glide vehicle (HGV) that can be carried as an MIRV payload by the UR-100UTTKh, R-36M2 and RS-28 Sarmat heavy ICBMs. It can deliver both nuclear and conventional payloads. The Avangard is reportedly capable of travelling at re-entry speeds.
A hypersonic weapon is a weapon capable of travelling at hypersonic speed, defined as between 5 and 25 times the speed of sound or about 1 to 5 miles per second.
Hypersonix Launch Systems is an Australian space startup developing scramjet and scramjet-based access-to-space technology. In particular, the company is focused on reusable "green-fuelled" launch technology. The company specialises in hypersonic vehicle and scramjet engines to provide sustainable and affordable access to space.
