Hypersonic flight is flight through the atmosphere below about 90km at speeds above Mach 5, a speed where dissociation of air begins to become significant and high heat loads exist. In such a regime the aerodynamic flow around a flight body is described by similarity parameters such as its Mach number and its Reynolds number.
- 1 History
- 2 Physics
- 3 Hypersonic weapons development
- 4 Flown aircraft
- 5 Cancelled aircraft
- 6 Developing and proposed aircraft
- 7 See also
- 8 References
- 9 External links
The first manufactured object to achieve hypersonic flight was the two-stage Bumper rocket, consisting of a WAC Corporal second stage set on top of a V-2 first stage. On February 1949, at White Sands, the rocket reached a speed of 5,150 miles per hour, or approximately Mach 6.7. The vehicle, however, burned on atmospheric re-entry, and only charred remnants were found. In April 1961, Russian Major Yuri Gagarin became the first human to travel at hypersonic speed, during the world's first piloted orbital flight. Soon after, in May 1961, Alan Shepard became the first American and second person to achieve hypersonic flight when his capsule reentered the atmosphere at a speed above Mach 5 at the end of his suborbital flight over the Atlantic Ocean.
The reentry problem of a space vehicle was extensively studied. The hypersonic regime has since become the subject for further study during the 21st century, and strategic competition between the US, Russia, and China.
The NASA X-43A flew on scramjet for 10 seconds, and then glided for 10 minutes on its last flight in 2004. The Boeing X-51 Waverider flew on scramjet for 210 seconds in 2013, finally reaching Mach 5.1 on its fourth flight test.
The stagnation point of air flowing around a body is a point where its local velocity is zero. At this point the air flows around this location. A shock wave forms, which deflects the air from the stagnation point and insulates the flight body from the atmosphere. This can affect the lifting ability of a flight surface to counteract its drag and subsequent free fall. Ning describes a method for interrelating Reynolds number with Mach number.
In order to maneuver in the atmosphere at faster speeds than supersonic, the forms of propulsion can still be airbreathing systems, but a ramjet no longer suffices for a system to attain Mach 5, as a ramjet slows down the airflow to subsonic. Some systems (waveriders) use a first stage rocket to boost a body into the hypersonic regime. Other systems (boost-glide vehicles) use scramjets after their initial boost, in which the speed of the air passing through the scramjet remains supersonic. Other systems (munitions) use a cannon for their initial boost.
Hypersonic weapons development
In the last year, China has tested more hypersonic weapons than we have in a decade. We've got to fix that.
Hypersonic weapons, by definition, travel five or more times the speed of sound. Hypersonic cruise missiles which are powered by scramjet are restricted below 100,000 feet; hypersonic glide vehicles can travel higher. Compared to a ballistic (parabolic) trajectory, a hypersonic vehicle would be capable of large-angle deviations from a parabolic trajectory. According to CNBC, Russia and China lead in hypersonic weapon development, trailed by the United States. France, India, and Australia may also be pursuing the technology.
In 2016, Russia is believed to have conducted multiple successful tests of Avangard, a hypersonic glide vehicle. In 2018, an Avangard was launched at the Dombarovskiy missile base, reaching its target at the Kura shooting range, a distance of 3700 miles. Avangard uses a scramjet engine. Avangard uses new composite materials which are to withstand temperatures of up to 2,000 degrees Celsius (3,632 degrees Fahrenheit). The Avangard's environment at hypersonic speeds reaches such temperatures. Russia considers its current carbon fiber solution to be unreliable.
These tests have prompted US responses in weapons development   per John Hyten's USSTRATCOM statement 05:03, 8 August 2018 (UTC). At least one vendor is developing ceramics to handle the temperatures of hypersonics systems. There are over a dozen US hypersonics projects as of 2018, notes the commander of USSTRATCOM.
According to Air Force Chief Scientist, Dr. Greg Zacharias, the US anticipates having hypersonic weapons by the 2020s, hypersonic drones by the 2030s and recoverable hypersonic drone aircraft by the 2040s. The focus of DoD development will be on air-breathing boost-glide hypersonics systems. Countering hypersonic weapons during their cruise phase will require radar with longer range, as well as space-based sensors, and systems for tracking and fire control.
Rand Corporation (28 September 2017) estimates there is less than a decade to prevent Hypersonic Missile proliferation. In the same way that anti-ballistic missiles were developed as countermeasures to ballistic missiles, counter-countermeasures to hypersonics systems are not yet in development.   
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Developing and proposed aircraft
- WU-14 (DF-ZF)
- Avatar (spacecraft)
- Advanced Technology Vehicle
- Falcon HTV-2
- Boeing Commercial Airplanes Hypersonic Airliner Concept
- Sänger II
Cruise missiles and warheads
- Advanced Hypersonic Weapon
- WU-14 (DF-ZF)
- Kh-45 (cancelled)
- Hypersonic Technology Demonstrator Vehicle
- / Brahmos-II
- Hypersonic speed
- Supersonic transport
- Lifting body
- Atmospheric entry
- List of X-planes
- Thunderbird 1
- Alfred J. Eggers, H. Julian Allen, Stanford Neice. (10 December 1954) NACA report 1382 "A comparative analysis of the performance of long-range hypervelocity vehicles" pp. 1141-1160
- Winter, Frank (2000-08-03). "V-2 missile". Smithsonian National Air and Space Museum. airandspace.si.edu. Retrieved 2018-08-16.
- White, Robert. "Across the Hypersonic Divide". HistoryNet. HistoryNet LLC. Retrieved 11 October 2015.
- "Hypersonic plane passes latest test - Just In - ABC News (Australian Broadcasting Corporation)". Abc.net.au. 2010-03-22. Retrieved 2014-02-18.
- MIT "Fluids" 1. Effects of Reynolds Number 2. Effects of Mach Number
- Andrew Ning "Matching Mach and Reynolds Number"
- Amanda Macias (21 March 2018; Updated 22 March 2018) Russia and China are 'aggressively developing' hypersonic weapons — here's what they are and why the US can't defend against them: America's top nuclear commander said the U.S. doesn't have defenses against hypersonic weapons. Russia and China are leading the way in developing hypersonic weapons.
- Garrett Reim (14 DECEMBER, 2018) Counter hypersonic weapon possible by mid-2020s: DoD
- 3 August 2018 China tests waverider hypersonic aircraft Starry Sky-2
- China successfully tests first hypersonic aircraft that can ..
- Youtube clip XingKong-2 hypersonic aircraft (Starry Sky-2)
- Macias, Amanda (26 December 2018). "The Kremlin says it conducted another successful test of a hypersonic weapon". www.cnbc.com. Retrieved 27 December 2018.
- (26 December 2018) Putin crows as he oversees Russian hypersonic weapons test
- Nick Stockton (27 Dec 2018) Rotating Detonation Engines Could Propel Hypersonic Flight
- (27 December 2018) Putin Says ‘Invulnerable’ New Hypersonic Nuclear Missile Is Ready For Deployment
- Amanda Macias (FRI, OCT 12 2018 • 1:43 PM EDT | UPDATED FRI, OCT 12 2018 • 6:37 PM EDT) Russia hits a snag in developing a hypersonic weapon after Putin said it was already in production
- Lockheed Martin Hypersonic Conventional Strike Weapon (HCSW) Missile for US Air Force
- Joseph Trevithick (6 September 2018) DARPA Starts Work On "Glide Breaker" Hypersonic Weapons Defense Project
- (14 August 2018) Lockheed Martin gets a second hypersonic weapons contract, this time for $480 million, as the US tries to keep pace with Russia and China
- Osborn, Kris. "Get Ready, Russia and China: America's Next Fighter Jet Will Dominate the Skies". The National Interest. Retrieved 2 March 2018.
- David Vergun (December 14, 2018) DOD scaling up effort to develop hypersonics
- Rand Corporation (28 September 2017) Hypersonic Missile Nonproliferation
- "Putin unveils new nuclear missile, says 'listen to us now'". nbcnews.com. Retrieved 2 March 2018.
- D. Preller and P. M. Smart, "Abstract: SPARTAN: Scramjet Powered Accelerator for Reusable Technology AdvaNcement," 2014. http://rispace.org/wp-content/uploads/2015/03/33_preller.pdf