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98-492: A waverider is a hypersonic aircraft design that improves its supersonic lift-to-drag ratio by using the shock waves being generated by its own flight as a lifting surface, a phenomenon known as compression lift . The waverider remains a well-studied design for high-speed aircraft in the Mach 5 and higher hypersonic regime, although no such design has yet entered production. The Boeing X-51 scramjet demonstration aircraft

196-426: A / v ) {\displaystyle \mu =\sin ^{-1}(a/v)} where a is the speed of the sound wave and v is the flow velocity. Since M=v/a, the equation becomes μ = sin − 1 ⁡ ( 1 / M ) {\displaystyle \mu =\sin ^{-1}(1/M)} . Higher Mach numbers position the shock wave closer to the body surface, thus at hypersonic speeds,

294-606: A Kinzhal with a Patriot . IBCS, or the Integrated Air and Missile Defense Battle Command System is an Integrated Air and Missile Defense (IAMD) capability designed to work with Patriots and other missiles. 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 were not yet in development, as of 2019. See

392-547: A pyramid -shaped design with a flat underside and short wings. Heat was conducted through the wings to the upper cool surfaces, where it was dumped into the turbulent air on the top of the wing. In 1960, work on the Blue Streak was canceled as the missile was seen as being obsolete before it could have entered service. Work then moved to the Royal Aircraft Establishment (RAE), where it continued as

490-579: A CNBC July 2019 report (and now in a CNN 2022 report), Russia and China lead in hypersonic weapon development, trailed by the United States, and in this case the problem is being addressed in a joint program of the entire Department of Defense. To meet this development need, the US Army is participating in a joint program with the US Navy and Air Force, to develop a hypersonic glide body. India

588-818: A Common Hypersonic Glide Body (C-HGB) in 2020. The Air Force dropped out of the tri-service hypersonic project in 2020, leaving only the Army and Navy on the C-HGB. 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. A mid-2021 report from

686-424: A considerable portion of their mission at high altitudes, and for these vehicles, low-density effects will become more significant. The flow field between the shock wave and the body surface is called the shock layer. As the Mach number M increases, the angle of the resulting shock wave decreases. This Mach angle is described by the equation μ = sin − 1 ⁡ (

784-732: A coordinated series of missile exercises, some of them hypersonic, were launched on 18 February 2022 in an apparent display of power projection . The launch platforms ranged from submarines in the Barents sea in the Arctic, as well as from ships on the Black sea to the south of Russia. The exercise included a RS-24 Yars ICBM, which was launched from the Plesetsk Cosmodrome in Northern Russia until it reached its destination on

882-454: A current pulse that could be scaled up to gigawatt scale, given enough argon gas to feed into the MHD generators. A rotating detonation engine (RDE) might propel airframes in hypersonic flight; on 14 December 2023 engineers at GE Aerospace demonstrated their test rig, which is to combine an RDE with a ramjet/ scramjet , in order to evaluate the regimes of rotating detonation combustion. The goal

980-528: A fire control system to accomplish an over-the-shoulder missile launch, which does not yet exist (2023). In February 2023, the DF-27 covered 1,900 km (1,200 mi) in 12 minutes, according to leaked secret documents . The capability directly threatens Guam, and US Navy aircraft carriers. In 2016, Russia is believed to have conducted two successful tests of Avangard , a hypersonic glide vehicle. The third known test, in 2017, failed. In 2018, an Avangard

1078-409: A given angle and then developing the body shape that traps that angle, then repeating this process for different angles. For any given speed, a single shape will generate the best results. During re-entry , hypersonic vehicles generate lift only from the underside of the fuselage . The underside, which is inclined to the flow at a high angle of attack , creates lift in reaction to the vehicle wedging

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1176-549: A multi-speed waverider is a " caret wing ", operated at different angles of attack. A caret wing is a delta wing with longitudinal conical or triangular slots or strakes . It strongly resembles a paper airplane or rogallo wing . The correct angle of attack would become increasingly precise at higher Mach numbers, but this is a control problem that is theoretically solvable. The wing is said to perform even better if it can be constructed of tight mesh, because that reduces its drag, while maintaining lift. Such wings are said to have

1274-609: A paper on a new 3D underside shape using these techniques. These shapes have superior lifting performance and less drag. Since then, whole families of cone -derived waveriders have been designed using more and more complex conic shocks, based on more complex software. This work eventually led to a conference in 1989, the First International Hypersonic Waverider Conference , held at the University of Maryland. These newest shapes,

1372-492: A range of 2,300 km (1,400 mi)". By adding rocket propulsion to a shell or glide body, the joint effort shaved five years off the likely fielding time for hypersonic weapon systems. Countermeasures against hypersonics will require sensor data fusion: both radar and infrared sensor tracking data will be required to capture the signature of a hypersonic vehicle in the atmosphere. There are also privately developed hypersonic systems, as well as critics. DoD tested

1470-455: A research program into high-speed (Mach 4 to 7) civilian airliners . This work was discovered by engineers at North American Aviation during the early design studies of what would lead to the XB-70 bomber. They re-designed the original "classic" delta wing to incorporate drooping wing tips in order to trap the shock waves mechanically, rather than using a shock cone generated from the front of

1568-469: A slight modification) remained on the obverse with a custom design by the host city on the reverse. Noting that Cassioli's design showed a Roman amphitheater for what originally were Greek games, a new obverse design was commissioned for the 2004 Summer Olympics in Athens . For the 2008 Beijing Olympics medals had a diameter of 70mm and were 6mm thick, with the front displaying a winged figure of victory and

1666-405: A space vehicle was extensively studied. 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 hypersonic regime has since become the subject for further study during the 21st century, and strategic competition between

1764-553: A sporting discipline receive a gold medal in recognition of their achievement. At the Ancient Olympic Games , only one winner per event received an award, which was a kotinos , an olive wreath made of wild olive leaves from a sacred tree near the temple of Zeus at Olympia. Aristophanes in Plutus makes a remark why victorious athletes are crowned with wreaths made of wild olive instead of gold. Herodotus describes

1862-548: A story that explains why there were only a few Greek men at the Battle of Thermopylae since "all other men were participating in the Olympic Games" and that the prize for the winner was "an olive-wreath". When Tigranes , an Armenian general, learned this, he uttered to his leader: "Good heavens! What kind of men are these against whom you have brought us to fight? Men who do not compete for possessions, but for honour". At

1960-726: A successful test of hypersonic technologies at Wallops Island . On 28 June 2024 DoD announced a successful recent end-to-end test of the US Army's Long-Range Hypersonic Weapon all-up round (AUR) and the US Navy's Conventional Prompt Strike. The missile was launched from the Pacific Missile Range Facility , Kauai, Hawaii. In September 2021, and in March 2022, US vendors Raytheon/Northrop Grumman, and Lockheed respectively, first successfully tested their air-launched, scramjet-powered hypersonic cruise missiles, which were funded by DARPA . By September 2022 Raytheon

2058-437: A way to control spanwise flow, and thereby increase the amount of air trapped under the wing in the same way as a wing fence . While working on these concepts, he noticed that it was possible to shape the wing in such a way that the shock wave generated off its leading edge would form a horizontal sheet under the craft. In this case, the airflow would not only be trapped horizontally, spanwise, but vertically as well. The only area

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2156-495: Is a medal awarded for highest achievement in a non-military field. Its name derives from the use of at least a fraction of gold in form of plating or alloying in its manufacture. Since the eighteenth century, gold medals have been awarded in the arts, for example, by the Royal Danish Academy of Fine Arts , usually as a symbol of an award to give an outstanding student some financial freedom. Others offer only

2254-533: Is absorbed by using the JP-7 fuel as a coolant prior to combustion. Other high temperature materials, referred to as SHARP materials (typically zirconium diboride and hafnium diboride ) have been used on steering vanes for ICBM reentry vehicles since the 1970s, and are proposed for use on hypersonic vehicles. They are said to permit Mach 11 flight at 100,000 ft (30,000 m) altitudes and Mach 7 flight at sea level. These materials are more structurally rugged than

2352-528: Is active: N 2 → 2N Consequently, in this temperature range, a plasma forms: —molecular dissociation followed by recombination of oxygen and nitrogen radicals produces nitric oxide: N 2 + O 2 → 2NO, which then dissociates and recombines to form ions: N + O → NO + e At standard sea-level condition for air, the mean free path of air molecules is about λ = 68 n m {\displaystyle \lambda =68\,\mathrm {nm} } . At an altitude of 104 km (65 mi), where

2450-524: Is also developing such weapons. France and Australia may also be pursuing the technology. Japan is acquiring both scramjet (Hypersonic Cruise Missile), and boost-glide weapons (Hyper Velocity Gliding Projectile). China's XingKong-2 (星空二号, Starry-sky-2 ), a waverider , had its first flight 3 August 2018. In August 2021 China launched a boost-glide vehicle to low-earth orbit, circling Earth before maneuvering toward its target location, missing its target by two dozen miles. However China has responded that

2548-457: Is called low-density flow. For a given aerodynamic condition low-density effects depends on the value of a nondimensional parameter called the Knudsen number K n {\displaystyle \mathrm {Kn} } , defined as K n = λ l {\displaystyle \mathrm {Kn} ={\frac {\lambda }{l}}} where l {\displaystyle l}

2646-447: 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; from which a future hypersonic cruise missile is sought, perhaps by Q4 FY2021. The Long range precision fires (LRPF) CFT is supporting Space and Missile Defense Command 's pursuit of hypersonics. Joint programs in hypersonics are informed by Army work; however, at

2744-486: Is no longer available as heat, so this shaping can dramatically reduce the heat load on the spacecraft. Such a design has been the basis for almost every re-entry vehicle since, found on the blunt noses of the early ICBM warheads, the bottoms of the various NASA capsules, and the large nose of the Space Shuttle . The problem with the blunt-nose system is that the resulting design creates very little lift, meaning

2842-411: Is that it has more area in contact with the shock wave and therefore has more pronounced heat dissipation problems. Waveriders generally have sharp noses and sharp leading edges on their wings. The underside shock-surface remains attached to this. Air flowing in through the shock surface is trapped between the shock and the fuselage, and can only escape at the rear of the fuselage. With sharp edges, all

2940-565: Is the typical length scale of the object considered. The value of the Knudsen number based on nose radius, K n = λ R {\displaystyle \mathrm {Kn} ={\frac {\lambda }{R}}} , can be near one. Hypersonic vehicles frequently fly at very high altitudes and therefore encounter low-density conditions. Hence, the design and analysis of hypersonic vehicles sometimes require consideration of low-density flow. New generations of hypersonic airplanes may spend

3038-699: Is to achieve sustainable turbine-based combined cycle (TBCC) propulsion systems, at speeds between Mach 1 and Mach 5. Transport consumes energy for three purposes: overcoming gravity, overcoming air/water friction, and achieving terminal velocity. The reduced trip times and higher flight altitudes reduce the first two, while increasing the third. Proponents claim that the net energy costs of hypersonic transport can be lower than those of conventional transport while slashing journey times. Stratolaunch Roc can be used to launch hypersonic aircraft. Hermeus demonstrated transition from turbojet aircraft engine operation to ramjet operation on 17 November 2022, thus avoiding

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3136-466: The 1896 Summer Olympics , winners received a silver medal and the second-place finisher received a bronze medal . In 1900 , most winners received cups or trophies instead of medals. The next three Olympics ( 1904 , 1908 , 1912 ) awarded the winners solid gold medals, but the medals themselves were smaller. The use of gold rapidly declined with the onset of the First World War and also with

3234-563: The Congressional Research Service states the United States is "unlikely" to field an operational hypersonic glide vehicle (HGV) until 2023. On 21 October 2021, the Pentagon stated that a test of a hypersonic glide body failed to complete because its booster failed; according to Lt. Cmdr. Timothy Gorman the booster was not part of the equipment under test, but the booster's failure mode will be reviewed to improve

3332-654: The Kamchatka Peninsula in Eastern Russia . Ukraine estimated a 3M22 Zircon was used against it, but apparently did not exceed Mach 3 and was shot down 7 February 2024 in Kyiv. These tests have prompted US responses in weapons development. By 2018, the AGM-183 and Long-Range Hypersonic Weapon were in development per John Hyten 's USSTRATCOM statement on 8 August 2018 (UTC). At least one vendor

3430-571: The Missile Defense Agency was funding regional countermeasures against hypersonic weapons in their glide phase . James Acton characterized the proliferation of hypersonic vehicles as never-ending in October 2021; Jeffery Lewis views the proliferation as additional arguments for ending the arms race. Doug Loverro assesses that both missile defense and competition need rethinking. CSIS assesses that hypersonic defense should be

3528-952: The National Defense Space Architecture (2021), above . But by 2019, $ 157.4 million was allocated in the FY2020 Pentagon budget for hypersonic defense, out of $ 2.6 billion for all hypersonic-related research. $ 207 million of the FY2021 budget was allocated to defensive hypersonics, up from the FY2020 budget allocation of $ 157 million. Both the US and Russia withdrew from the Intermediate-Range Nuclear Forces (INF) Treaty in February 2019. This will spur arms development, including hypersonic weapons, in FY2021 and forward. By 2021

3626-608: The Reinforced Carbon Composite (RCC) used on the space shuttle nose and leading edges, have higher radiative and temperature tolerance properties, and do not suffer from oxidation issues that RCC needs to be protected against with coatings. A surface material for waverider and hypersonic ( Mach 5 – 10) vehicles developed by scientists at the China Academy of Aerospace Aerodynamics (CAAA) in Beijing

3724-523: The Under Secretary of Defense for Research and Engineering (USD(R&E)) is pursuing a program of annual rapid joint experiments, including hypersonics capabilities, to bring down their cost of development. A hypersonic test bed aims to bring the frequency of tests to one per week. France , Australia , India , Germany , Japan , South Korea , North Korea , and Iran also have hypersonic weapon research programs. Australia and

3822-406: The fuselage towards the tips. When viewed from the front, the wing resembles a caret symbol ( [REDACTED] ) in cross section , and these designs are often referred to as carets. The more modern 3D version typically looks like a rounded letter 'M'. Theoretically, a star-shaped waverider with a frontal cross-section of a "+" or "×" could reduce drag by another 20%. The disadvantage of this design

3920-789: The prestige of the award. Many organizations now award gold medals either annually or extraordinarily, including various academic societies. While some gold medals are solid gold, others are gold-plated or silver-gilt , like those of the Olympic Games , the Lorentz Medal , the United States Congressional Gold Medal and the Nobel Prize medal. Nobel Prize medals consist of 18  karat green gold plated with 24 karat gold. Before 1980, they were struck in 23 karat gold. Before

4018-462: The "osculating cones waverider", which develops several conical shock waves at different points on the body, blending them to produce a single shaped shock. The expansion to a wider range of compression surface flows allowed the design of waveriders with control of volume, upper surface shape, engine integration and centre of pressure position. Performance improvements and off-design analysis continued until 1970. During this period at least one waverider

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4116-402: The "viscous optimized waveriders", look similar to conical designs as long as the angle of the shock wave on the nose is beyond some critical angle, about 14 degrees for a Mach 6 design for instance. The angle of the shock can be controlled by widening out the nose into a curved plate of specific radius, and reducing the radius produces a smaller shock cone angle. Vehicle design starts by selecting

4214-540: The 1950s, the British started a space program based around the Blue Streak missile , which was, at some point, to include a crewed vehicle. Armstrong-Whitworth were contracted to develop the re-entry vehicle, and unlike the U.S. space program, they decided to stick with a winged vehicle instead of a ballistic capsule . Between 1957 and 1959, they contracted Nonweiler to develop his concepts further. This work produced

4312-519: The 19th century, with the National Association of Amateur Athletes in the United States awarding such medals as early as 1884. This standard was adopted for Olympic competition at the 1904 Summer Olympics in St. Louis . At the 1896 event , silver was awarded to winners and bronze to runners-up, while in 1900 other prizes were given, not medals. At the modern Olympic Games , winners of

4410-459: The Olympic host. From 1928 through 1968 the design was always the same: the obverse showed a generic design by Florentine artist Giuseppe Cassioli of Greek goddess Nike with Rome's Colosseum in the background and text naming the host city; the reverse showed another generic design of Nike saluting an Olympic champion. From the 1972 Summer Olympics through 2000 , Cassioli's design (or

4508-462: The US have begun joint development of air-launched hypersonic missiles, as announced by a Pentagon statement on 30 November 2020. The development will build on the $ 54 million Hypersonic International Flight Research Experimentation (HIFiRE) under which both nations collaborated on over a 15-year period. Small and large companies will all contribute to the development of these hypersonic missiles, named SCIFIRE in 2022. In May 2023 Ukraine shot down

4606-625: The US' priority over hypersonic weapons. As part of their Hypersonic vehicle tracking mission, the Space Development Agency (SDA) launched four satellites and the Missile Defense Agency (MDA) launched two satellites on 14 February 2024 (launch USSF-124). The satellites will share the same orbit, which allows the SDA's wide field of view (WFOV) satellites and the MDA's medium field of view (MFOV) downward-looking satellites to traverse

4704-453: The United States, India, Russia, and China. 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 . In order to maneuver in

4802-444: The accuracy needed for a precision weapon; the second launch by China demonstrated its ability to change trajectories, according to Pentagon reports on the 2021 competition in arms capabilities. In 2022, China unveiled two more hypersonic models. An AI simulation has revealed that a Mach 11 aircraft can simply outrun a Mach 1.3 fighter attempting to engage it, while firing its missile at the "pursuing" fighter. This strategy entails

4900-410: The air above the shock wave could escape would be out the back of the sheet where the fuselage ended. Since the air was trapped between this sheet and the fuselage, a large volume of air would be trapped, much more than the more basic approach he first developed. Furthermore, since the shock surface was held at a distance from the craft, shock heating was limited to the leading edges of the wings, lowering

4998-424: The air is thinner, the mean free path is λ = 1 f t = 0.305 m {\displaystyle \lambda =1\,\mathrm {ft} =0.305\,\mathrm {m} } . Because of this large free mean path aerodynamic concepts, equations, and results based on the assumption of a continuum begin to break down, therefore aerodynamics must be considered from kinetic theory. This regime of aerodynamics

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5096-406: The aircraft. This mechanism also had two other beneficial effects; it reduced the amount of horizontal lifting surface at the rear of the aircraft, which helped offset a nose-down trim that occurs at high speeds, and it added more vertical surface which helped improve the directional stability, which decreased at high speed. Nonweiler's original design used the shock wave generated by the aircraft as

5194-501: The airflow downwards. The amount of lift is not particularly high, compared to a traditional wing , but more than enough to maneuver given the amount of distance the vehicle covers. Most re-entry vehicles have been based on the blunt-nose reentry design pioneered by Theodore von Kármán . He demonstrated that a shock wave is forced to "detach" from a curved surface, forced out into a larger configuration that requires considerable energy to form. Energy expended in forming this shock wave

5292-407: The atmosphere at faster speeds than supersonic, the forms of propulsion can still be airbreathing systems, but a ramjet does not suffice 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

5390-515: The atmosphere, and ballistic missiles travel in the vacuum above the atmosphere. However, they can use the atmosphere to manoeuvre, making them capable of large-angle deviations from a ballistic trajectory. A hypersonic glide vehicle is usually launched with a ballistic first stage, then deploys wings and switches to hypersonic flight as it re-enters the atmosphere, allowing the final stage to evade all existing nuclear missile defense systems, which were designed for ballistic-only missiles. According to

5488-649: The back showed a Beijing Olympics symbol surrounded by an inset jade circle. Winter Olympics medals have been of more varied design. The silver and bronze medals have always borne the same designs. The award of a gold medal, often coupled with the award of silver and bronze medals to the next place finishers, has been adopted in other sports competitions (such as the Mediterranean Games ), and in other competitive fields, such as music and writing, as well as some competitive games. Typically bronze medals are awarded only to third place, but in some contests there

5586-473: The body surface. Although the shock wave at the nose at supersonic speeds is also curved, the entropy layer is only observed at hypersonic speeds because the magnitude of the curve is far greater at hypersonic speeds. Researchers in China have used shock waves in a detonation chamber to compress ionized argon plasma waves moving at Mach 14. The waves are directed into magnetohydrodynamic (MHD) generators to create

5684-410: The bottom (extremely long gliding profiles at high altitude), and the Space Shuttle somewhere in the middle. Simple waveriders have substantial design problems. First, the obvious designs only work at a particular Mach number , and the amount of lift captured will change dramatically as the vehicle changes speed. Another problem is that the waverider depends on radiative cooling , possible as long as

5782-490: The boundary layer starts to interact with the air trapped between the shock wave and the fuselage, the air that is being used for lift on a waverider. Calculating the effects of these interactions was beyond the abilities of aerodynamics until the introduction of useful computational fluid dynamics starting in the 1980s. In 1981, Maurice Rasmussen at the University of Oklahoma started a waverider renaissance by publishing

5880-422: The caret wing waverider in the later 1960s as a part of a three-stage lunar rocket design. The first stage was built on an expanded Blue Steel , the second a waverider, and the third a nuclear-powered crewed stage. This work was generalized in 1971 to produce a two-staged reusable spacecraft. The 121-foot (37 m) long first stage was designed as a classical waverider, with air-breathing propulsion for return to

5978-485: The center and the two sides folded downward. From the rear it looks like an upside-down V, or alternately, the " caret ", ^, and such designs are known as "caret wings". Two to three years later the concept briefly came into the public eye, due to the airliner work at the RAE that led to the prospect of reaching Australia in 90 minutes. Newspaper articles led to an appearance on Scottish Television . Hawker Siddeley examined

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6076-694: The establishment of standard military awards , e.g., the Medal of Honor , it was common practice to have a medal specially created to provide national recognition for a significant military or naval victory or accomplishment. In the United States, Congress would enact a resolution asking the President to reward those responsible. The commanding officer would receive a gold medal and his officers would get silver medals . Medals have historically been given as prizes in various types of competitive activities, especially athletics. Traditionally, medals are made of

6174-400: The exponential reliance on the Mach number. Since the boundary layer becomes so large, it interacts more viscously with the surrounding flow. The overall effect of this interaction is to create a much higher skin friction than normal, causing greater surface heat flow. Additionally, the surface pressure spikes, which results in a much larger aerodynamic drag coefficient. This effect is extreme at

6272-652: The following metals: Occasionally, Platinum medals can be awarded. These metals designate the first three Ages of Man in Greek mythology : the Golden Age , when men lived among the gods, the Silver Age , where youth lasted a hundred years, and the Bronze Age , the era of heroes. The custom of awarding the sequence of gold, silver , and bronze medals for the first three highest achievers dates from at least

6370-475: The generation of missiles" and has a speed above Mach 13. but Col. Rob Lodwick, the spokesman for the Pentagon on Middle East affairs said that there are doubts in this regard. In 2021, DoD was codifying flight test guidelines, knowledge gained from Conventional Prompt Strike (CPS), and the other hypersonics programs, for some 70 hypersonics R&D programs alone, as of 2021. In 2021-2023, Heidi Shyu ,

6468-490: The heat of re-entry. At the time, Nonweiler was forced to use a greatly simplified 2D model of airflow around the aircraft, which he realized would not be accurate due to spanwise flow across the wing. However, he also noticed that the spanwise flow would be stopped by the shockwave being generated by the aircraft, and that if the wing was positioned to deliberately approach the shock, the spanwise flow would be trapped under wing, increasing pressure, and thus increasing lift. In

6566-438: The high kinetic energy is converted in part to internal energy and gas energy is proportional to the internal energy. Therefore, hypersonic boundary layers are high temperature regions due to the viscous dissipation of the flow's kinetic energy. Another region of high temperature flow is the shock layer behind the strong bow shock wave. In the case of the shock layer, the flow's velocity decreases discontinuously as it passes through

6664-429: The launch site. The upper stage was designed as a lifting body, and would have carried an 8000-pound (3.6 t) payload to low Earth orbit . Nonweiler's work was based on studies of planar 2D shocks due to the difficulty understanding and predicting real-world shock patterns around 3D bodies. As the study of hypersonic flows improved, researchers were able to study waverider designs that used different shockwave shapes,

6762-414: The leading edge and decreases as a function of length along the surface. The entropy layer is a region of large velocity gradients caused by the strong curvature of the shock wave. The entropy layer begins at the nose of the aircraft and extends downstream close to the body surface. Downstream of the nose, the entropy layer interacts with the boundary layer which causes an increase in aerodynamic heating at

6860-408: The lift is retained. Even though sharp edges get much hotter than rounded ones at the same air density, the improved lift means that waveriders can glide on re-entry at much higher altitudes where the air density is lower. A list ranking various space vehicles in order of heating applied to the airframe would have capsules at the top (re-entering quickly with very high heating loads), waveriders at

6958-536: The need to boost aircraft velocities by rocket or scramjet. Two main types of hypersonic weapons are hypersonic cruise missiles and hypersonic glide vehicles . Hypersonic weapons, by definition, travel five or more times the speed of sound. Hypersonic cruise missiles, which are powered by scramjets , are limited to below 30 km (19 mi); hypersonic glide vehicles can travel higher. Hypersonic vehicles are much slower than ballistic (i.e. sub-orbital or fractional orbital) missiles, because they travel in

7056-524: The onset of the Second World War . The last series of Olympic medals to be made of solid gold were awarded at the 1912 Summer Olympics in Stockholm , Sweden . Olympic gold medals are required to be made from at least 92.5% silver , and must contain a minimum of 6 grams of gold. All Olympic medals must be at least 70mm in diameter and 3mm thick. Minting the medals is the responsibility of

7154-545: The same terrain of Earth. The SDA's four satellites are part of its Tranche 0 tracking layer (T0TL). The MDA's two satellites are HBTSS or Hypersonic and ballistic tracking space sensors. Additional capabilities of Tranche 0 of the National defense space architecture (NDSA), also known as the Proliferated warfighting space architecture (PWSA) will be tested over the next two years. Gold Medal A gold medal

7252-508: The shock wave lies extremely close to the body surface, resulting in a thin shock layer. At low Reynolds number, the boundary layer grows quite thick and merges with the shock wave, leading to a fully viscous shock layer. The compressible flow boundary layer increases proportionately to the square of the Mach number, and inversely to the square root of the Reynolds number. At hypersonic speeds, this effect becomes much more pronounced, due to

7350-482: The shock wave. This results in a loss of kinetic energy and a gain of internal energy behind the shock wave. Due to high temperatures behind the shock wave, dissociation of molecules in the air becomes thermally active. For example, for air at T > 2,000 K (1,730 °C; 3,140 °F), dissociation of diatomic oxygen into oxygen radicals is active: O 2 → 2O For T > 4,000 K (3,730 °C; 6,740 °F), dissociation of diatomic nitrogen into N radicals

7448-431: The shock waves generated from the nose of the aircraft. Normally the boundary layer is quite thin compared to the streamline of airflow over the wing, and can be considered separately from other aerodynamic effects. However, as the speed increases and the shock wave increasingly approaches the sides of the craft, there comes a point where the two start to interact and the flowfield becomes very complex. Long before that point,

7546-410: The shock. Like the caret wing, they have to be designed to operate at a specific speed to properly attach the shock wave to the wing's leading edge, but unlike them the entire body shape can be varied dramatically at the different design speeds, and sometimes have wingtips that curve upward to attach to the shockwave. Further development of the conical sections, adding canopies and fuselage areas, led to

7644-402: The simplest being the conical shock generated by a cone. In these cases, a waverider is designed to keep the rounded shockwave attached to its wings, not a flat sheet, which increases the volume of air trapped under the surface, and thereby increases lift. Unlike the caret wing, the cone flow designs smoothly curve their wings, from near horizontal in the center, to highly drooped where they meet

7742-428: The speed of the air passing through the scramjet remains supersonic. Other systems ( munitions ) use a cannon for their initial boost. Hypersonic flow is a high energy flow. The ratio of kinetic energy to the internal energy of the gas increases as the square of the Mach number. When this flow enters a boundary layer, there are high viscous effects due to the friction between air and the high-speed object. In this case,

7840-522: The strategic level, the bulk of the hypersonics work remains at the Joint level. Long Range Precision Fires (LRPF) is an Army priority, and also a DoD joint effort. The Army and Navy's Common Hypersonic Glide Body (C-HGB) had a successful test of a prototype in March 2020. A wind tunnel for testing hypersonic vehicles was completed in Texas (2021). The Army's Land-based Hypersonic Missile "is intended to have

7938-544: The test setup. The test occurred at Pacific Spaceport Complex – Alaska , on Kodiak island. Three rocketsondes at Wallops Island completed successful tests earlier that week, for the hypersonics effort. On 29 October 2021 the booster rocket for the Long-Range Hypersonic Weapon was successfully tested in a static test; the first stage thrust vector control system control system was included. On 26 October 2022 Sandia National Laboratories conducted

8036-546: The thermal loads on the fuselage. In 1962 Nonweiler moved to Glasgow University to become Professor of Aerodynamics and Fluid Mechanics. That year his "Delta Wings of Shapes Amenable to Exact Shock-Wave Theory" was published by the Journal of the Royal Aeronautical Society , and earned him that society's Gold Medal . A craft generated using this model looks like a delta wing that has been broken down

8134-553: The unusual attribute of operating at a wide range of Mach numbers in different fluids with a wide range of Reynolds numbers . The temperature problem can be solved with some combination of a transpiring surface, exotic materials, and possibly heat-pipes . In a transpiring surface, small amounts of a coolant such as water are pumped through small holes in the aircraft's skin (see transpiration and perspiration ). This design works for Mach 25 spacecraft re-entry shields , and therefore should work for any aircraft that can carry

8232-401: The upper part of the wing through the gap between the leading edge and the detached shock wave. This loss of airflow reduced (by up to a quarter) the lift being generated by the waverider, which led to studies on how to avoid this problem and keep the flow trapped under the wing. Nonweiler's resulting design is a delta-wing with some amount of negative dihedral — the wings are bent down from

8330-526: The vehicle has problems maneuvering during re-entry. If the spacecraft is meant to be able to return to its point of launch "on command", then some sort of maneuvering will be required to counteract the fact that the Earth is turning under the spacecraft as it flies. After a single low Earth orbit , the launching point will be over 1,000 km (600 mi) to the east of the spacecraft by the time it has completed one full orbit. A considerable amount of research

8428-559: The vehicle spends most of its time at very high altitudes. However these altitudes also demand a very large wing to generate the needed lift in the thin air, and that same wing can become rather unwieldy at lower altitudes and speeds. Because of these problems, waveriders have not found favor with practical aerodynamic designers, despite the fact that they might make long-distance hypersonic vehicles efficient enough to carry air freight . Some researchers controversially claim that there are designs that overcome these problems. One candidate for

8526-483: The vehicle was a spacecraft, and not a missile; there was a July 2021 test of a spaceplane, according to Chinese Foreign Ministry Spokesperson Zhao Lijian ; Todd Harrison points out that an orbital trajectory would take 90 minutes for a spaceplane to circle Earth (which would defeat the mission of a weapon in hypersonic flight). The US DoD's headquarters (The Pentagon) reported in October 2021 that two such hypersonic launches have occurred; one launch did not demonstrate

8624-616: The weapon was first fielded to the Yasnensky Missile Division, a unit in the Orenburg Oblast . In an earlier report, Franz-Stefan Gady named the unit as the 13th Regiment/Dombarovskiy Division (Strategic Missile Force). In 2021 Russia launched a 3M22 Zircon antiship missile over the White Sea , as part of a series of tests. " Kinzhal and Zircon (Tsirkon) are standoff strike weapons". In February 2022,

8722-491: The weight of the coolant. Exotic materials such as carbon-carbon composite do not conduct heat but endure it, but they tend to be brittle . Heatpipes are not widely used at present. Like a conventional heat exchanger , they conduct heat better than most solid materials, but like a thermosiphon are passively pumped. The Boeing X-51A deals with external heating through the use of a tungsten nosecone and space shuttle-style heat shield tiles on its belly. Internal (engine) heating

8820-695: The world's first piloted orbital flight . Soon after, in May 1961, Alan Shepard became the first American and second person to fly hypersonic when his capsule reentered the atmosphere at a speed above Mach 5 at the end of his suborbital flight over the Atlantic Ocean. In November 1961, Air Force Major Robert White flew the X-15 research aircraft at speeds over Mach 6. On 3 October 1967, in California, an X-15 reached Mach 6.7. The reentry problem of

8918-536: Was believed to have constructed their first hypersonic missile. Amir Ali Hajizadeh , the commander of the Air Force of the Islamic Republic of Iran's Revolutionary Guards Corps, announced the construction of the Islamic Republic's first hypersonic missile. He noted: "This new missile was produced to counter air defense shields and passes through all missile defense systems and which represents a big leap in

9016-487: Was dedicated to combining the blunt-nose system with wings, leading to the development of the lifting body designs in the U.S. It was while working on one such design that Nonweiler developed the waverider. He noticed that the detachment of the shock wave over the blunt leading edges of the wings of the Armstrong-Whitworth design would allow the air on the bottom of the craft to flow spanwise and escape to

9114-665: Was launched at the Dombarovskiy missile base , reaching its target at the Kura shooting range , a distance of 5,955 km (3,700 mi). Avangard uses new composite materials which are to withstand temperatures of up to 2,000 °C (3,630 °F). The Avangard's environment at hypersonic speeds reaches such temperatures. Russia considered its carbon fiber solution to be unreliable, and replaced it with new composite materials. Two Avangard hypersonic glide vehicles (HGVs) will first be mounted on SS-19 ICBMs; on 27 December 2019

9212-475: Was selected for fielding Hypersonic Attack Cruise Missile (HACM), a scramjet-powered hypersonic missile by FY2027. In March 2024 Stratolaunch Roc launched TA-1, a vehicle which is nearing Mach 5 at 10.67 km (6.63 mi) in a powered flight, a risk-reduction exercise for TA-2. In a similar development Castelion launched its low-cost hypersonic platform in the Mojave desert, in March 2024. In 2022, Iran

9310-485: Was tested at the Woomera Rocket Range , mounted on the nose of an air-launched Blue Steel missile , and a number of airframes were tested in the wind tunnel at NASA's Ames Research Center . However, during the 1970s most work in hypersonics disappeared, and the waverider along with it. One of the many differences between supersonic and hypersonic flight concerns the interaction of the boundary layer and

9408-542: Was tested during 2023. An alternative developed by RTX Corporation uses a perspiring membrane developed under work supported by the United States Air Force under Contract No. United States Air Force FA8650-20-C-7001 Hypersonic aircraft Hypersonic vehicles are able to maneuver through the atmosphere in a non-parabolic trajectory , but their aerodynamic heat loads need to be managed. The first manufactured object to achieve hypersonic flight

9506-464: Was tested from 2010 to 2013. In its final test flight, it reached a speed of Mach 5.1 (5,400 km/h; 3,400 mph). The waverider design concept was first developed by Terence Nonweiler of the Queen's University of Belfast , and first described in print in 1951 as a re-entry vehicle. It consisted of a delta-wing platform with a low wing loading to provide considerable surface area to dump

9604-432: Was the two-stage Bumper rocket, consisting of a WAC Corporal second stage set on top of a V-2 first stage. In February 1949, at White Sands , the rocket reached a speed of 8,290 km/h (5,150 mph), or about 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

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