Hypersonic flight

Flight below 90 km and faster than Mach 5

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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.[1]

Reentry vehicle (RV) after an 8,000-kilometre (5,000 mi) flight, 1959. Note the blackened tip of the RV due to aerodynamic heating. Compare to the aerodynamic heating effect on the iron meteorite on the right.

Hypersonic vehicles are able to maneuver through the atmosphere in a non-parabolic trajectory, but their aerodynamic heat loads need to be managed.

## History

[edit]

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. In February 1949, at White Sands, the rocket reached a speed of 8,290 km/h (5,150 mph), or about Mach 6.7.[2] 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 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.[3]

In November 1961, Air Force Major Robert White flew the X-15 research aircraft at speeds over Mach 6.[4][5] On 3 October 1967, in California, an X-15 reached Mach 6.7.[6]

The reentry problem of a space vehicle was extensively studied.[7] 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 of further study during the 21st century, and strategic competition between the United States, India, Russia, and China.[8]

## Physics

[edit]

Main article: Hypersonic speed

### Stagnation point

[edit]

The stagnation point of air flowing around a body is a point where its local velocity is zero.[7] 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.[7] This can affect the lifting ability of a flight surface to counteract its drag and subsequent free fall.[9][a]

In order to maneuver in 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.[11] 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.[12]

### High temperature effect

[edit]

Hypersonic flow is a high energy flow.[13] 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, 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 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: O2 → 2O[14]: 41 [15][16] For T > 4,000 K (3,730 °C; 6,740 °F), dissociation of diatomic nitrogen into N radicals is active: N2 → 2N[14]: 39 Consequently, in this temperature range, a plasma forms:[17] —molecular dissociation followed by recombination of oxygen and nitrogen radicals produces nitric oxide: N2 \+ O2 → 2NO, which then dissociates and recombines to form ions: N + O → NO+ \+ e−[14]: 39 [18]

### Low density flow

[edit]

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 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 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} 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 a considerable portion of their mission at high altitudes, and for these vehicles, low-density effects will become more significant.[13]

### Thin shock layer

[edit]

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 ⁡ ( 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, 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.[19]

### Viscous interaction

[edit]

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 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 the leading edge and decreases as a function of length along the surface.[13]

### Entropy layer

[edit]

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 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.[13]

## Propulsion

[edit]

### Controlled detonation

[edit]

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 a current pulse that could be scaled up to gigawatt scale, given enough argon gas to feed into the MHD generators.[20]

### Rotating detonation

[edit]

A rotating detonation engine (RDE)[21] 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 is to achieve sustainable turbine-based combined cycle (TBCC) propulsion systems, at speeds between Mach 1 and Mach 5.[22][23][24]

### Hybrid

[edit]

Companies such as Hermeus, Venus Aerospace, and AstroMechanica are developing hybrid engines capable of operating from subsonic to hypersonic speeds.

Hybrid engines  Company  | 0-3  | 3-4  | 5+

|
|
|

Hermeus[25] | Precooled P&W F100 turbojet  | Dive  | Ramjet
Venus Aerospace[25] | Rotating detonation  | Ramjet  | Ramjet
AstroMechanica[26] | Turbofan  | Turbojet  | Ramjet

## Applications

[edit]

### Shipping

[edit]

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.[27]

Stratolaunch Roc can be used to launch hypersonic aircraft.[28]

Hermeus demonstrated transition from turbojet aircraft engine operation to ramjet operation on 17 November 2022,[29] thus avoiding the need to boost aircraft velocities by rocket or scramjet.[30]

See: SR-72, § Mayhem

### Weapons

[edit]

Main article: Hypersonic weapon

Hypersonic weapon, demonstrating its non-parabolic trajectory (denoted in red), has a distinctive signature which is being tracked by one of the layers of the National Defense Space Architecture (§ NDSA) beginning in 2021. Tranche 0 is to begin deployment in 2022.[31]

* The satellites of the NDSA, in gray, are to be deployed in constellations orbiting Earth, and constantly keep Earth in their view, depicted by the blue cones representing the fields of view of the satellite constellations. The satellites are to intercommunicate and serve the defensive systems arrayed against enemy hypersonic vehicles, and build a kill chain against them.
* Conversely, the same satellites can be used to track friendly hypersonic weapons and perform battle damage assessment of their strikes against targets. See JADC2 (Joint all-domain command and control)

Two main types of hypersonic weapons are hypersonic cruise missiles and hypersonic glide vehicles.[b][36] 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);[c] 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 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.[11] 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 existing missile defense systems which were designed for ballistic-only missiles.[39]

According to 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,[40][41][42][8][43] and in this case the problem is being addressed in a joint program of the entire Department of Defense.[44] 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.[52] India is also developing such weapons.[53] France and Australia may also be pursuing the technology.[11] Japan is acquiring both scramjet (Hypersonic Cruise Missile), and boost-glide weapons (Hyper Velocity Gliding Projectile).[54]

#### China

[edit]

China's XingKong-2 (星空二号, Starry-sky-2), a waverider, had its first flight 3 August 2018.[55][56][57][58] 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.[59][60] However China has responded that the vehicle was a spacecraft, and not a missile;[61] there was a July 2021 test of a spaceplane, according to Chinese Foreign Ministry Spokesperson Zhao Lijian;[62][63][64] 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).[62] The US DoD's headquarters (The Pentagon) reported in October 2021 that two such hypersonic launches have occurred; one launch did not demonstrate the accuracy needed for a precision weapon;[59] the second launch by China demonstrated its ability to change trajectories, according to Pentagon reports on the 2021 competition in arms capabilities.[65]

In 2022, China unveiled two more hypersonic models.[66][67] 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.[68] This strategy entails a fire control system to accomplish an over-the-shoulder missile launch, which does not yet exist (2023).[68]

In February 2023, the DF-27 covered 1,900 km (1,200 mi) in 12 minutes, according to leaked secret documents.[69] The capability directly threatens Guam, and US Navy aircraft carriers.[69]

#### Russia

[edit]

In 2016, Russia is believed to have conducted two successful tests of Avangard, a hypersonic glide vehicle. The third known test, in 2017, failed.[70] In 2018, an Avangard was launched at the Dombarovskiy missile base, reaching its target at the Kura shooting range, a distance of 5,955 km (3,700 mi).[71] Avangard uses new composite materials which are to withstand temperatures of up to 2,000 °C (3,630 °F).[72] The Avangard's environment at hypersonic speeds reaches such temperatures.[72] Russia considered its carbon fiber solution to be unreliable,[73] and replaced it with new composite materials.[72] Two Avangard hypersonic glide vehicles (HGVs)[74] will first be mounted on SS-19 ICBMs; on 27 December 2019 the weapon was first fielded to the Yasnensky Missile Division, a unit in the Orenburg Oblast.[75] In an earlier report, Franz-Stefan Gady named the unit as the 13th Regiment/Dombarovskiy Division (Strategic Missile Force).[74] In 2021 Russia launched a 3M22 Zircon antiship missile over the White Sea, as part of a series of tests.[76] "Kinzhal and Zircon (Tsirkon) are standoff strike weapons".[77] In February 2022, 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 the Kamchatka Peninsula in Eastern Russia.[78] 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.[79]

#### United States

[edit]

See also: Prompt Global Strike

These tests have prompted US responses in weapons development.[80] By 2018, the AGM-183[81] and Long-Range Hypersonic Weapon[82] were in development per John Hyten's USSTRATCOM statement on 8 August 2018 (UTC).[83] At least one vendor is developing ceramics to handle the temperatures of hypersonics systems.[84] There are over a dozen US hypersonics projects as of 2018, notes the commander of USSTRATCOM;[83][85][82][86][87][88] from which a future hypersonic cruise missile is sought, perhaps by Q4 FY2021.[89][90][91] The Long range precision fires (LRPF) CFT is supporting Space and Missile Defense Command's pursuit of hypersonics.[94] Joint programs in hypersonics are informed by Army work;[95][96] however, at the strategic level, the bulk of the hypersonics work remains at the Joint level.[101] Long Range Precision Fires (LRPF) is an Army priority, and also a DoD joint effort.[96] The Army and Navy's Common Hypersonic Glide Body (C-HGB) had a successful test of a prototype in March 2020.[102][100] A wind tunnel for testing hypersonic vehicles was completed in Texas (2021).[103] The Army's Land-based Hypersonic Missile "is intended to have a range of 2,300 km (1,400 mi)".[104]: p.6 [51][105][106][107][108] 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.[109][110] 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.[115] There are also privately developed hypersonic systems,[116] as well as critics.[117][118]

DoD tested a Common Hypersonic Glide Body (C-HGB) in 2020.[102][119] The Air Force dropped out of the tri-service hypersonic project in 2020, leaving only the Army and Navy on the C-HGB.[120][121][122] According to Air Force chief scientist, Dr. Greg Zacharias, the US anticipates having hypersonic weapons by the 2020s,[123] hypersonic drones by the 2030s, and recoverable hypersonic drone aircraft by the 2040s.[124] The focus of DoD development will be on air-breathing boost-glide hypersonics systems.[125] 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.[125][126][111][127] A mid-2021 report from the Congressional Research Service states the United States is "unlikely" to field an operational hypersonic glide vehicle (HGV) until 2023.[128]

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 the test setup.[129] The test occurred at Pacific Spaceport Complex – Alaska, on Kodiak island.[130] Three rocketsondes at Wallops Island completed successful tests earlier that week, for the hypersonics effort.[130] 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.[131] On 26 October 2022, Sandia National Laboratories conducted a successful test of hypersonic technologies at Wallops Island.[132][133] 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.[134]

In September 2021, and in March 2022, US defense contractors Raytheon/Northrop Grumman,[135][136][137] and Lockheed[138][139] respectively, first successfully tested their air-launched, scramjet-powered hypersonic cruise missiles, which were funded by DARPA.[c] By September 2022 Raytheon was selected for fielding Hypersonic Attack Cruise Missile (HACM), a scramjet-powered hypersonic missile by FY2027.[140][141]

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.[142] In a similar development, Castelion launched its low-cost hypersonic platform in the Mojave desert, in March 2024.[143]

In 2021, DoD was codifying flight test guidelines, knowledge gained from Conventional Prompt Strike (CPS), and the other hypersonics programs,[144] for some 70 hypersonics R&D programs alone, as of 2021.[145][146] In 2021–2023, Heidi Shyu, the Under Secretary of Defense for Research and Engineering (USD(R&E)) pursued a program of annual rapid joint experiments,[147] including hypersonics capabilities, to bring down the cost of development.[148][149] A hypersonic test bed aims to bring the frequency of tests to one per week.[150][151]

#### Iran

[edit]

In 2022, Iran 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 the generation of missiles"[152] and has a speed above Mach 13.[153] but Col. Rob Lodwick, the spokesman for the Pentagon on Middle East affairs said that there are doubts in this regard.[154]

#### Other programs

[edit]

France,[128] Australia,[128] India,[155] Germany,[128] Japan,[128] South Korea,[156] North Korea,[157] and Iran[158] also have ongoing hypersonic weapon projects or research programs.[128]

Australia and 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.[159] Small and large companies will all contribute to the development of these hypersonic missiles,[160] named SCIFIRE in 2022.[161][140]

## Defenses

[edit]

In May 2023 Ukraine shot down a Kinzhal with a Patriot.[162] 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 2017 assessment

Rand Corporation (28 September 2017) estimates there is less than a decade to prevent Hypersonic Missile proliferation.[163] 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.[11][164][73][165] See 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.[104] $207 million of the FY2021 budget was allocated to defensive hypersonics, up from the FY2020 budget allocation of $157 million.[145][166][50] 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,[167][168] in FY2021 and forward.[169] By 2021 the Missile Defense Agency was funding regional countermeasures against hypersonic weapons in their glide phase.[170][171][172] 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.[173] Doug Loverro assesses that both missile defense and competition need rethinking.[174] CSIS assesses that hypersonic defense should be the US' priority over hypersonic weapons.[175][d][176][177]

### NDSA / PWSA

[edit]

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).[178][179] 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 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.[e]

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.[179][184]

## Proposed

[edit]

Aircraft

Artist depiction of the Halcyon commercial hypersonic transport aircraft proposed by the Hermeus corporation in flight.

* I-Plane[185]
* 14-X
* Espadon hypersonic combat aircraft concept (program conducted by the ONERA)[186][187]
* Avatar (spacecraft)[188]
* Advanced Technology Vehicle[189]
* DARPA XS-1[190]
* Destinus hydrogen-powered hypersonic aircraft. A prototype was tested last year.[191][27][192]
* Dream Chaser[193]
* NASA X-43[194][195]
* HyperSoar[196]
* HyperStar hypersonic passenger airliner[197]
* Falcon HTV-2[198]
* Boeing Commercial Airplanes hypersonic airliner Concept[199][200]
* Lockheed Martin SR-72[201]
* Kholod
* Ayaks waverider spaceplane
* Programme for Reusable In-orbit Demonstrator in Europe (PRIDE)
* Sänger II[202]
* HyShot
* Hytex[203]
* Horus[204]
* SHEFEX
* Skylon[205]
* Reaction Engines A2
* Hypersonic Air Vehicle Experimental (HVX)[206][207] with Concept V aircraft[208]
* Spartan[209]
* HEXAFLY[210]
* SpaceLiner[211]
* STRATOFLY[212]
* Zero Emission Hyper Sonic Transport
* Hermeus Quarterhourse unmanned hypersonic demonstrator designed to land and take-off on conventional runways.[213]
* Hermeus Halcyon hypersonic transport[214]
* Venus Aerospace Stargazer hypersonic airliner[215] with rotating detonation rocket engine[216][217]
* POLARIS Raumflugzeuge GmbH is developing and testing a hypersonic spaceplane for the German Armed Forces in Peenemünde[218][219]

Bombers

* Expendable Hypersonic Air-Breathing Multi-Mission Demonstrator ("Mayhem")[220] Based on § HAWC and HSSW: "solid rocket-boosted, air-breathing, hypersonic conventional cruise missile", a follow-on to AGM-183A. As of 2020 no design work had been done. By 2022 Mayhem was to be tasked with ISR and strike missions,[221] as a possible bomber.[222][223] Leidos is preparing a system requirements review, and a conceptual design for these missions.[224] Draper Labs has begun a partnership with Leidos.[223] Kratos is preparing a conceptual design for Mayhem, using Air Force Research Laboratory (AFRL) digital engineering techniques in a System design agent team, a collaboration with Leidos, Calspan, and Draper.[225] DIU is soliciting additional Hypersonic and High-Cadence Airborne Testing Capabilities (HyCAT), for Mayhem.[226]

Cruise missiles

* Advanced Hypersonic Weapon (AHW)[227]
* Hypersonic Air-breathing Weapon Concept (HAWC, pronounced "hawk"). September 2021: HAWC is DARPA-funded. Built by Raytheon and Northrop Grumman, HAWC is the first US scramjet-powered hypersonic missile to successfully complete a free flight test in the 2020s.[228][135][136][229][104] DARPA's goals for the test, which were successfully met, were: "vehicle integration and release sequence, safe separation from the launch aircraft, booster ignition and boost, booster separation and engine ignition, and cruise".[135] HAWC is capable of sustained, powered maneuver in the atmosphere.[137]: minute 0:55 HAWC appears to depend on a rocket booster to accelerate to scramjet velocities operating in an oxygen-rich environment.[230][231] It is easier to put a seeker on a sub-sonic air-breathing vehicle.[232] In mid-March 2022 a HAWC Scramjet was successfully tested in an air-launched flight by a second vendor.[138][139] On 18 July 2022 Raytheon announced another successful test of its Hypersonic Air-breathing Weapon Concept (HAWC) scramjet, in free flight.[233][234]
1. MoHAWC is a follow-on to DARPA's HAWC project. MoHAWC will seek "to further develop the vehicle’s scramjet propulsion system, upgrade integration algorithms, reduce the size of navigation components, and improve its manufacturing approach".[235]
* Hypersonic Conventional Strike Weapon (HCSW - pronounced "hacksaw")[122] passed its critical design review (CDR)[236] but this IDIQ (indefinite duration, indefinite quantity)[236] contract was terminated in favor of ARRW because twice as many ARRWs will fit on a bomber.[237]
* ASN4G (air-launched, scramjet-powered, hypersonic cruise missile under development by MBDA France and the ONERA to succeed the ASMP)[238][239]
* Kh-45 (cancelled)
* Zircon[240][241]
* Hypersonic Technology Demonstrator Vehicle
* / Brahmos-II
* Hycore[156]

Glide vehicles

* AGM-183A air launched rapid response weapon (ARRW, pronounced "arrow")[229][242][104][243] Telemetry data has been successfully transmitted from ARRW —AGM-183A IMV-2 (Instrumented Measurement Vehicle) to the Point Mugu ground stations, demonstrating the ability to accurately broadcast radio at hypersonic speeds;[244][245] however, ARRW's launch sequence was not completed, as of 15 Dec 2021.[91][246][247] Hundreds of ARRWs or other Hypersonic weapons are being sought by the Air Force.[248] On 9 March 2022 Congress halved funding for ARRW and transferred the balance to ARRW's R&D account to allow for further testing, which puts the procurement contract at risk.[249] A production decision on ARRW has been delayed for a year to complete flight testing.[250][251] On 14 May 2022 an ARRW flight test was successfully completed, for the first time.[252][253] There have been 3 successful tests of ARRW in 2022; however the Air Force is requiring 3 additional successful tests of an All-Up Round (AUR) before making a production decision.[254] No production decision will be made in 2024.[234] The USAF now intends to end the ARRW development program, as of 29 March 2023.[255][256][141][257][258] A B-52 flying out of Anderson AFB in Guam fired an All-Up-Round AGM-183A Air-launched Rapid Response Weapon (ARRW); the AUR was tested at Reagan test site in the Pacific on 17 March 2024.[259]
* DARPA Tactical Boost Glide vehicle[260][261][262]
* VMaX-2 hypersonic glide vehicle (under development by ArianeGroup; first flight test scheduled for 2025)[263][238][239]
* HGV-202F

## Flown

[edit]

Aircraft

* North American X-15 (crewed)[264]
* Lockheed X-17[265]
* NASA X-43
* Boeing X-51[266]
* HSTDV[267]

Glide vehicles

* Avangard[268]
* DF-ZF
* Hwasong-8[157]
* Hwasong-12A (official designation unconfirmed)
* Hwasong-16B
* Unnamed[157]
* VMaX (developed by ArianeGroup; first flight test took place on 26 June 2023 and was a success)[269][270][271][272][273]

Spaceplanes

* Space Shuttle orbiter (crewed)
* Buran (human-rated, only flew without crew)[274]
* RLV-TD[275]
* Boeing X-37[276]
* Shenlong[277]
* IXV[278]
* BOR-4[279]
* Martin X-23 PRIME[280]
* ASSET[281]
* HYFLEX[282]
* Reusable experimental spacecraft (disputed)
* Jiageng-1[283]

## Cancelled

[edit]

Aircraft

* Silbervogel (Sänger bomber)[284]
* Keldysh bomber[285]
* Tupolev Tu-360, follow-on to Tu-160
* Tupolev Tu-2000[286]
* Lockheed L-301

Glide vehicles

* VERAS (hypersonic glide vehicle program launched in 1965 and cancelled in 1971)[287][288]

Spaceplanes

* Boeing X-20 Dyna-Soar
* Rockwell X-30 (National Aerospace Plane)
* Orbital Sciences X-34
* Mikoyan-Gurevich MiG-105
* Tsien Spaceplane 1949[289]
* HOPE-X[290]
* XCOR Lynx
* Lockheed Martin X-33[291]
* Hermes[292]
* Prometheus[293]
* HL-20 Personnel Launch System
* HL-42
* BAC Mustard[294]
* Kliper[295]
* HOTOL
* Valier Raketenschiff[296]
* Rockwell C-1057[297]

## See also

[edit]

* Hypersonic effect
* Supersonic transport
* Lifting body
* List of X-planes
* Thunderbird 1

## Notes

[edit]

1. ^ Ning describes a method for interrelating Reynolds number with Mach number.[10]
2. ^ "[N]on-nuclear capabilities may be able to complement nuclear forces in strategic deterrence plans"—The 2022 Nuclear Posture Review[32]: 33rd-62nd pages as cited by Loren Thompson.[33] Thus non-nuclear hypersonics serve as proportionate deterrent layers in the defense strategy of the United States.[32] [34] [35]
3. ^ a b According to Alex Hollings, as 21 March 2022 no nation has yet successfully fielded a scramjet-powered hypersonic cruise missile, including Russia's 3M22 Zircon.[37]: minute 10:14 However, tests of DARPA's Hypersonic Air-breathing Weapon Concept (HAWC) have now succeeded, using designs by two different vendors in September 2021, and March 2022 respectively.[38]
4. ^ In the CSIS report and discussion of Hypersonic missile defense, one of the panelists, Kelley M. Sayler (Congressional Research Service) summarized the situation (as of 7 February 2022) and quoted Michael Griffin's assessment that Hypersonic cruise missiles are 10 to 20 times dimmer than ballistic missiles.[175]: min 19:00–21:00 [176]
5. ^ Space development agency (SDA) provides the PWSA wide field of view (WFOV) sensors; Missile defense agency (MDA) provides the Hypersonic and Ballistic Tracking Space Sensor (HBTSS) sensors, (i.e., the Medium Field of View (MFOV) sensors). The WFOV sensors provide cueing data to the MFOV sensors, which are more sensitive and provide tipping data to the earth-based interceptors.[180] as cited in USNI News.[181] Two WFOV satellites were launched as part of the inititial Tranche 0.[182][183]

## References

[edit]

1. ^ Uppal, Rajesh. "Hypersonic Aircraft race for commercial and military". International Defense Security & Technology. Retrieved 2 January 2025.
2. ^ Winter, Frank (3 August 2000). "V-2 missile". Smithsonian National Air and Space Museum. airandspace.si.edu. Archived from the original on 4 January 2017. Retrieved 16 August 2018.
3. ^ Altitude reached: 116 miles, velocity reached: 5134 mph, or Mach 8.5
4. ^ White, Robert. "Across the Hypersonic Divide". HistoryNet. HistoryNet LLC. Retrieved 11 October 2015.
5. ^ "Hypersonic plane passes latest test". ABC News (Australian Broadcasting Corporation). 22 March 2010. Archived from the original on 18 July 2012. Retrieved 18 February 2014.
6. ^ Gibbs, Yvonne (13 August 2015). "NASA Dryden Fact Sheets - X-15 Hypersonic Research Program". NASA.
7. ^ a b c Alfred J. Eggers, H. Julian Allen, Stanford Neice (10 December 1954), "A comparative analysis of the performance of long-range hypervelocity vehicles", NACA report 1382, pp. 1141–1160
8. ^ a b In, for example Waverider hypersonic weapons delivery, China has flown a Mach 5.5 vehicle for 400 seconds, at 30 km altitude, demonstrating large-angle deviations from a ballistic trajectory, as well as recovery of the payload. See
* 3 August 2018 China tests hypersonic aircraft Starry Sky-2 \--Xingkong-2 (Starry-sky-2) first flight
* China successfully tests first hypersonic aircraft that can ..  Youtube clip XingKong-2 hypersonic aircraft (Starry Sky-2)
* USSTRATCOM John Hyten statement 05:03, 8 August 2018 (UTC)
* (15 Jun 2018) Lockheed Martin Hypersonic Conventional Strike Weapon (HCSW) Missile for US Air Force
* Chris Martin (17 Dec 2019) Lockheed awards $81.5M contract for hypersonic missile motor to Rocketdyne for HCSW $81.5M, ARRW
* NPR (23 October 2018) Nations Rush Ahead With Hypersonic Weapons Amid Arms Race Fear
* DOV S. ZAKHEIM, OPINION CONTRIBUTOR (08/26/19) Putin built a hypersonic arsenal, while the Pentagon slept
* Colin Clark (19 June 2019) Raytheon, Northrop Will ‘Soon’ Fly Hypersonic Cruise Missile Paris Air Show, new additive-process materials to build the combustor of a scramjet; potential integration among members of an intercommunicating swarm of hypersonics systems
* DRDO successfully flight tests hypersonic technology vehicle (September 7, 2020) Express News Service, The Indian Express
Current test targets, such as Zombie Pathfinder are not hypersonic. Rand Corporation (28 September 2017) Hypersonic Missile Nonproliferation estimates there is less than a decade to prevent Hypersonic Missile proliferation.
9. ^ "MIT "Fluids" 1. Effects of Reynolds Number 2. Effects of Mach Number" (PDF). Retrieved 9 October 2020.
10. ^ "Andrew Ning "Matching Mach and Reynolds Number"" (PDF). Retrieved 9 October 2020.
11. ^ a b c d Amanda Macias (21 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.", CNBC
12. ^ Jared Keller "Watch the Air Force use a hypersonic bullet to blast a drone out of the sky". 15 September 2020.
13. ^ a b c d Anderson, John (2016). Introduction to Flight (Eighth ed.) McGraw-Hill Education
14. ^ a b c B. deB. Darwent, National Bureau of Standards (Jan 1970) Table of Bond Dissociation Energies in Simple Molecules BDE: bond dissociation enthalpy
15. ^ Jim Clark (12 Feb 2022)Physical and Theoretical Chemistry Textbook Maps/Supplemental Modules (Physical and Theoretical Chemistry)/Thermodynamics/Energies and_Potentials/Enthalpy/Bond Bond Enthalpies
16. ^ Answered by ron, stack exchange (29 May 2014) Will heating diatomic oxygen enough break the O=O bonds?
17. ^ Jan Tegler (4 Oct 2019) Research at Hyper Speed: The Pentagon's Research Laboratories Are Working Flat Out to Develop Hypersonic Weapons Technology operating at 8,000 K (7,730 °C; 13,940 °F)
18. ^ Anthony Capaccio (28 Mar 2023) U.S. Hypersonic Missile Test Marred by In-Flight Data Loss ARRW plagued by loss of telemetry data in the latest test
19. ^ "Mach Angle". Glenn Research Center, NASA. 6 April 2018.
20. ^ Tim Newcomb (6 Feb 2023) China Built a Hypersonic Generator That Could Power Unimaginable Weapons
21. ^ MRO Business Today (9 Oct 2023) RTX to build Gambit engine for DARPA; PRnewswire (4 Oct 2023) RTX to develop rotating detonation engine for DARPA
22. ^ Joseph Trevithic (14 Dec 2023) GE's Breakthrough In 'Detonating' Hypersonic Propulsion Is A Big Deal; GE Aerospace (14 Dec 2023) GE Aerospace Demonstrates Hypersonic Dual-Mode Ramjet with Rotating Detonation Combustion
23. ^ Eric Berger (27 Mar 2024) The company building a rotating detonation engine is pushing the tech forward Venus Aerospace: Mach 0.9 at 12,000 feet
24. ^ Peter Ray Allison Superfast drone fitted with new 'rotating detonation rocket engine' approaches the speed of sound
25. ^ a b Wang, Brian (1 March 2025). "Gamchanging Hypersonic Drones from Venus Aerospace and Hermeus". NextBigFuture.com. Retrieved 6 April 2025.
26. ^ McCormick, Packy. "Astro Mechanica". www.notboring.co. Retrieved 6 April 2025.
27. ^ a b Blain, Loz (9 February 2022). ""Russia's Elon Musk" is developing hypersonic rocket cargo planes". New Atlas. Retrieved 10 February 2022.
28. ^ Camille Fine (20 Jan 2023) The biggest plane in the world has wings longer than a football field. See its latest flight
29. ^ "Hermeus Completes Hypersonic Engine Milestone". Hermeus. Retrieved 17 November 2022.
30. ^ Valerie Insinna (28 Mar 2024) Hermeus rolls out new uncrewed aircraft as company edges toward goal of hypersonic flight
31. ^ "SDA Awards Contracts for the First Generation of the Tracking Layer – Space Development Agency". www.sda.mil.
32. ^ a b Lloyd Austin III, US Secretary of Defense, et. al. (27 Oct 2022) 2022 National Defense Strategy of the United States, including the 2022 Nuclear Posture Review, and the 2022 Missile Defense Review 80 pages: Unclassified. NDS (1st-32nd pages); NPR (33rd-62nd pages); MDR (63rd-80th pages)
33. ^ Loren Thompson (20 Dec 2022) Ten Ways Hypersonic Weapons Can Strengthen Strategic Deterrence
34. ^ US Department of Defense (28 Mar 2022) Fact Sheet: 2022 National Defense Strategy 2 page sketch NDS
35. ^ Colin Kahl, US Department of Defense (4 Nov 2022) The 2022 National Defense Strategy: A conversation with Colin Kahl 2 hour discussion of NDS presented by the Brookings Institution
36. ^ "Hypersonic Weapons: Background and Issues for Congress" (PDF). Congressional Research Service.
37. ^ Alex Hollings, Sandboxx (21 Mar 2022) Don't believe the hype around Russia's hypersonic Kinzhal missile Kinzhal does not use a scramjet
38. ^ Alex Hollings (7 Apr 2022) AMERICA MAY HAVE JUST TAKEN THE LEAD IN HYPERSONIC CRUISE MISSILE TECHNOLOGY Archived 22 March 2023 at the Wayback Machine 2 tests of Hypersonic Air-breathing Weapon Concept (HAWC) using 2 different vendors
39. ^ Mark Zastrow (2021-11-04), "How does China's hypersonic glide vehicle work?", Astronomy
40. ^ CNN (1 Jun 2022) Russia and China are ahead of US in hypersonic missile technology. Here's why
41. ^ Valerie Insinna (2 Jun 2022) Lockheed’s CEO wants to fund a hypersonic wind tunnel, but says DoD isn’t buying in
42. ^ Miller, Jeff Morganteen, Andrea (26 September 2019). "Hypersonic weapons are the center of a new arms race between China, the US and Russia". CNBC.`{{cite web}}`: CS1 maint: multiple names: authors list (link)
43. ^ Stephen Carlson (14 Nov 2018) DARPA issues contract proposition for hypersonic missile defense
* Stephen Carlson (13 Nov 2018) Space, lasers, hypersonic missiles rank high for U.S. missile defense research
44. ^ Sydney Freedberg, Jr. Katz, Justin (22 August 2018). "Army Warhead Is Key To Joint Hypersonics".
45. ^ Paul McLeary (31 January 2020) SecNav Tells Fleet Hypersonic Competition Demands ‘Sputnik Moment;’ Glide Body Test Set Hypersonic Glide Body test for 2020
46. ^ Sean Kimmons, Army News Service "Joint hypersonic weapon tests to start next year". www.army.mil. 8 October 2019.
47. ^ Colin Clark "Army Moves Out On Lasers, Hypersonics: Lt. Gen. Thurgood". 24 May 2019.
48. ^ Sydney J. Freedberg Jr. (28 Feb 2020) Army Ramps Up Funding For Laser Shield, Hypersonic Sword  In FY2021 HELs funding is up 209 percent; LRHW funding is up 86 percent. RCCTO spending is $1 billion in 2021.
49. ^ a b Joe Lacdan "The Army joins the Air Force, Navy in attempt to develop hypersonic weaponry". www.army.mil. 24 October 2018.
50. ^ a b Kelley M. Sayler, Analyst in Advanced Technology and Global Security. Congressional Research Service R45811 (11 July 2019) Hypersonic Weapons: Background and Issues for Congress Lists names for hypersonics programs
51. ^ a b c Sydney J. Freedberg Jr. (30 August 2019) Hypersonics: Army Awards $699M To Build First Missiles For A Combat Unit prototypes—Dynetics: Common hypersonic glide body (C-HGB); Lockheed: Long range hypersonic weapon (LRHW)
* Nancy Jones-Bonbrest, U.S. Army RCCTO (30 August 2019) Army awards hypersonic weapon system contracts
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53. ^ "India successfully test-fires hypersonic missile carrier, 4th country to achieve the feat". ThePrint. 7 September 2020. Retrieved 8 September 2020.
54. ^ Yeo, Mike (13 March 2020). "Japan unveils its hypersonic weapons plans". Defense News.
55. ^ "China tests waverider hypersonic aircraft Starry Sky-2", 3 August 2018
56. ^ "China successfully tests first hypersonic aircraft that can carry nuclear warheads – Times of India". The Times of India. 6 August 2018.
57. ^ "Youtube clip XingKong-2 hypersonic aircraft (Starry Sky-2)". YouTube. 7 August 2018. Retrieved 9 October 2020.
58. ^ Holmes Liao (8 Oct 2021) China's Development of Hypersonic Missiles and Thought on Hypersonic Defense Publication: China Brief Volume: 21 Issue: 19  Critique of JF-12 hypersonic wind tunnel, as well as the newer JF-22 detonation-driven ultra-high-speed and high-enthalpy shock tunnel (used for XingKong). "PLA strategists fear that the U.S. may deploy hypersonic weapons on the first island chain and/or the second island chain, directly threatening China."
59. ^ a b Tyler Rogoway (16 Oct 2021) China Tested A Fractional Orbital Bombardment System That Uses A Hypersonic Glide Vehicle: Report
60. ^ "China surprises U.S. with hypersonic missile test, FT reports". Reuters. 17 October 2021 - via www.reuters.com.
61. ^ Hannah Ritchie, CNN (18 October 2021) China denies testing a nuclear-capable hypersonic missile, says it was a spacecraft
62. ^ a b Hitchens, Theresa (19 October 2021). "After China's 'Hypersonic' Test, US Alarm And Many Unanswered Questions".
63. ^ Trevithick, Joseph (18 October 2021). "China's Claim That Its Fractional Orbital Bombardment System Was A Spaceplane Test Doesn't Add Up (Updated)". The Drive.
64. ^ Demetri Sevastopulo, Washington (OCTOBER 20 2021) China conducted two hypersonic weapons tests this summer
65. ^ David E Sanger, and William J Broad The New York Times (28 Oct 2021) "China, Testing New Weapon, Jolts Pentagon"
66. ^ Mike Yeo (10 Nov 2022) China displays air-launched hypersonic missile at air show near Taiwan Mockups of 2PZD-21 thought to be air-launched versions of YJ-21
67. ^ Tanmay Kadam (13 Nov 2022) China Unveils World's 1st Carrier-Based Hypersonic Anti-Ship Missile 'YJ-21' That Can 'Strike The Eagle' "China has finally unveiled its 'YJ-21', or the 'Eagle Strike 21' shipborne hypersonic anti-ship missile that has long been shrouded in mystery. The missile has been put on display at the ongoing Zhuhai Air Show".
68. ^ a b Stephen Chen, SCMP (28 Feb 2023) Chinese AI simulates hypersonic air battle, offering surprising tactic for winning Mach 11 dogfight
69. ^ a b Geoff Ziezulewicz (18 Apr 2023) Pentagon: Yes, we are still lagging behind China's hypersonics DF-27
70. ^ Macias, Amanda (26 December 2018). "The Kremlin says it conducted another successful test of a hypersonic weapon". CNBC. Retrieved 27 December 2018.
71. ^ "Putin crows as he oversees Russian hypersonic weapons test", ABC News, 26 December 2018
72. ^ a b c "Putin Says 'Invulnerable' New Hypersonic Nuclear Missile Is Ready For Deployment", The Huffington Post, 27 December 2018
73. ^ a b Amanda Macias (12 October 2018), "Russia hits a snag in developing a hypersonic weapon after Putin said it was already in production", CNBC
74. ^ a b Franz-Stefan Gady (14 November 2019) Russia: Avangard Hypersonic Warhead to Enter Service in Coming Weeks: "The Russian Strategic Missile Force will receive the first two ICBMs fitted with the Avangard warhead in late November or early December." The Avangard HGV was codenamed Yu-71, under Project 4202. "In late November – early December, two UR-100N UTTKh missiles equipped with the hypersonic glide vehicles from the first regiment of Avangard systems will assume experimental combat duty in the Dombarovsky division of the Strategic Missile Force,"—Tass, 13 November. The "13th regiment will reportedly be the first unit to receive the two retrofitted SS-19 ICBMs. The regiment is part of the Dombarovskiy (Red Banner) missile division". Eventually 4 more SS-19s fitted with Avangard HGVs will join the 13th Regiment; a second regiment with six Avangard / SS-19s will be stood up by 2027.
75. ^ Vladimir Isachenkov (27 December 2019) "New Russian weapon can travel 27 times the speed of sound", Associated Press. —Avangard has been fielded to the Yasnensky Missile Division, a unit in the Orenburg Oblast —"The first regiment with the 'Avangard' took up combat duty" На боевое дежурство заступил первый полк с "Авангардами" (in Russian). Interfax. 27 December 2019.
* "Russia commissions intercontinental hypersonic weapon", NBC News, Associated Press, 27 December 2019.
76. ^ AP (29 Nov 2021) Russian Navy test-fires hypersonic missile in the White Sea
77. ^ Roger McDermott (7 Feb 2022) The Role of Hypersonic Weapons in Russian Military Strategy Giperzvukovogo Oruzhiya—(GZO); or Giperzvukovyye letatel’nyye apparaty—(GZLA) Kinzhal, Tsirkon, Kalibr, Poseidon, Avangard, Burevestnik, Sarmat,
78. ^ CNN (19 Feb 2022)
79. ^ Lewis Page Russia's 'Zircon' hypersonic super weapon has failed in Ukraine. Putin is egg-faced again
80. ^ Prakash Nanda, Eurasian Times (6 Nov 2022) Hypersonic Hype? This Is Why US 'Trails' Russia, China & Even North Korea In Hypersonic Missile Development
81. ^ "Lockheed Martin gets a second hypersonic weapons contract, this time for $480 million, as the US tries to keep pace with Russia and China", 14 August 2018, CNBC-- $480 million
82. ^ a b Sydney Freedberg (13 March 2019), "Hypersonics Won't Repeat Mistakes Of F-35", Breaking Defense
* "Navy: Conventional Prompt Strike (CPS)"
* "Army: Land-Based Hypersonic Missile"
* "Air Force: HCSW and ARRW"
* "DARPA & Air Force: Tactical Boost-Glide (TBG) and Hypersonic Air-breathing Weapon Concept (HAWC)"
83. ^ a b USSTRATCOM, CNBC
84. ^ Nick Stockton (27 December 2018), "Rotating Detonation Engines Could Propel Hypersonic Flight", Wired
85. ^ Colin Clark (28 Oct 2021) 'Hundreds' Of China Hypersonic Tests Vs. 9 US; Hyten Says US Moves Too Slowly
86. ^ Joseph Trevithick (6 September 2018), "DARPA Starts Work On 'Glide Breaker' Hypersonic Weapons Defense Project", The Drive
87. ^ Patrick Tucker (13 January 2020) The US Wants to Intimidate China with Hypersonics, Once It Solves the Physics 2020 review
88. ^ Joseph Trevithic (6 August 2019), "Air Force Reveals Tests Of Supposed Record-Setting Scramjet Engine From Northrop Grumman"
89. ^ Reim2020-04-30T00:42:00+01:00, Garrett. "US Air Force launches study of another hypersonic cruise missile". Flight Global. Retrieved 9 October 2020.`{{cite web}}`: CS1 maint: numeric names: authors list (link)
90. ^ THERESA HITCHENS and AARON MEHTA "As Air Force Signals Hypersonic Doubts, Key Senators Want To Go Faster". 24 September 2021.
91. ^ a b Valerie Insinna (20 Dec 2021) Air Force hypersonic weapon runs into trouble after a third failed test
92. ^ Mary Kate Aylward (5 February 2019) Experiments in hyperspeed more on Prompt Global Strike
93. ^ Megan Eckstein (3 November 2017) Navy Conducts Flight Test to Support Conventional Prompt Strike From Ohio-Class SSGNs 1st hypersonic glide vehicle test (Flight experiment 1)
94. ^ [49][92][93]
95. ^ "Army Futures Command aims to tap into innovative culture in Austin and beyond". www.army.mil. 16 August 2018.
96. ^ a b "Long-range precision fires modernization a joint effort, Army tech leader says". www.army.mil. 23 August 2018.
97. ^ Aaron Gregg (2 August 2019) In conversations with investors, defense firms double down on hypersonic weapons As of August 2019, Lockheed reports $3.5 billion in hypersonics work, while Raytheon reports $1.6 billion; Boeing declined to give the value of its hypersonics awards.
98. ^ Sydney J. Freedberg Jr. Katz, Justin (1 March 2018). "DoD Boosts Hypersonics 136 % In 2019: DARPA".
99. ^ Jason Cutshaw (19 September 2018) Secretary of the Navy visits AMC, SMDC memorandum of agreement in June to co-develop a hypersonic vehicle
100. ^ a b Jon Harper (4 March 2020) JUST IN: Pentagon to Spend Billions Mass-Producing Hypersonic Weapons "Aero shells that provide thermal protection for the high-speed platforms will be a key component of the systems"
101. ^ [97][98][99][100][51]
102. ^ a b Sydney J. Freedberg Jr. (20 Mar 2020) Hypersonics: Army, Navy Test Common Glide Body  "The U.S. Navy and U.S. Army jointly executed the launch of a common hypersonic glide body (C-HGB), which flew at hypersonic speed to a designated impact point. "
* DoD (20 March 2020) Department of Defense tests hypersonic glide body "The C-HGB – when fully fielded – will comprise the weapon's conventional warhead, guidance system, cabling, and thermal protection shield." Also: comments from LTG L. Neill Thurgood RCCTO
103. ^ University Strategic Communications (18 May 2021) New hypersonic facility accelerates UTSA as leader in aerospace projects At 15 m (49 ft) long and weighing more than 3,200 kg (7,100 lb), it operates at the UTSA Hypersonics Lab
104. ^ a b c d Kelley M. Sayler (11 July 2019), "Hypersonic Weapons: Background and Issues for Congress", Congressional Research Service
105. ^ Justin Katz (2 Feb 2022) Pentagon developing ‘National Defense Science and Technology’ strategy: Memo 14 technologies
106. ^ Brandi Vincent (4 Feb 2022) Pentagon Previews New Tech Strategy, Updates Priorities List for upcoming National Defense Science and Technology Strategy
107. ^ Courtney Albon and Joe Gould (4 Feb 2022) Top Pentagon officials met with industry executives about hypersonics. What comes next? a range of concerns
108. ^ Naval News Staff (1 Nov 2022) Hypersonic Missiles: Evolution Or Revolution?  summary overview
109. ^ Gary Sheftick "Army aligning modernization programs with other services". www.army.mil. 12 February 2019.
110. ^ Sydney J. Freedberg Jr. (11 September 2018) Aiming The Army's Thousand-Mile Missiles Multi-domain Ft Sill
111. ^ a b John L. Dolan, Richard K. Gallagher & David L. Mann (23 April 2019) Hypersonic Weapons – A Threat to National Security Hypersonic and Ballistic Tracking Space Sensor (HBTSS)
* Kris Osborn (16 December 2019) Pentagon Advances New Technology to Destroy Hypersonic Missile Attacks HBTSS will "establish a continuous 'track' on approaching hypersonic missiles"
* Melanie Marlowe (8 April 2020) Three obstacles are slowing space sensors for hypersonic threats Continuous tracking is needed to maintain custody of a hypersonic threat before its disposition.
* David Brennan (27 Jan 2021) Pentagon Orders Hypersonic Missile Trackers Amid Russia, China Arms Race HBTSS awards to L3Harris; Northrop Grumman
112. ^ Theresa Hitchens (24 February 2020) 2021 Budget Will Finally Fully Fund Next-Gen OPIR, Says Roper  Space-Based Infrared System (SBIRS) replacement: three satellites in Geosynchronous Orbit (GEO) and two satellites in a polar orbit
113. ^ Jen Judson (20 August 2019) US Missile Defense Agency boss reveals his goals, challenges on the job Increase the discrimination of the radars and other sensors. Use large aperture sensors. Use Space-based missile sensors. An SM-3 Block IIA missile test against ICBM is scheduled for 2020. Plan out the detection, control, and engagement; the sensors, the command-and-control, the fire control, and the weapons (the kill vehicles).
114. ^ Theresa Hitchens Katz, Justin (9 October 2020). "SDA Missile Tracking A 'Strategic Win' For L3Harris, SpaceX".
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116. ^ Colin Clark (19 June 2019), "Raytheon, Northrop Will 'Soon' Fly Hypersonic Cruise Missile", Breaking Defense, Paris Air Show, new additive-process materials to build the combustor of a scramjet; potential integration among members of an intercommunicating swarm of hypersonics systems.
117. ^ Shannon Bugos Katz, Justin (29 September 2021). "Congress Shouldn't Rubber-Stamp Hypersonic Weapons".
118. ^ Ashish Dangwal "Hypersonic Missiles: US Draws Big Plan To Track, Intercept & Shoot-Down Chinese Super-Maneuverable Threats". Latest Asian, Middle-East, EurAsian, Indian News. 10 December 2021.
119. ^ "Pentagon to TestFly New Hypersonic Weapon This Year". www.nationaldefensemagazine.org.
120. ^ Bryan Clark (21 April 2020) DoD Is Running the Wrong Way in the Hypersonics Race 230 kg (510 lb) payload; maneuverability at Mach 5 is an issue; possible red herring for funding
121. ^ JOSEPH TREVITHICK Trevithick, Joseph (11 February 2020). "Air Force Bails On Tri-Service Hypersonic Weapon Project As Army, Navy Ask For More Money". The Drive.
122. ^ a b "Lockheed Martin Hypersonic Conventional Strike Weapon (HCSW) Missile for US Air Force". YouTube. 15 June 2018. Retrieved 9 October 2020. $928 million
123. ^ Sean Kimmons (31 May 2019), "Joint hypersonic weapon tests to start next year", Army News Service
124. ^ Osborn, Kris (12 August 2017). "Get Ready, Russia and China: America's Next Fighter Jet Will Dominate the Skies". The National Interest. Retrieved 2 March 2018.
125. ^ a b David Vergun (14 December 2018), "DOD scaling up effort to develop hypersonics", U.S. Army
126. ^ Loren Thompson (30 July 2019) "Defense Against Hypersonic Attack Is Becoming The Biggest Military Challenge Of The Trump Era"
127. ^ Paul McLeary (18 December 2019), "MDA Kickstarts New Way To Kill Hypersonic Missiles" MDA's Hypersonic Defense Weapon System – 4 Interceptors
128. ^ a b c d e f Kelley M. Sayler (8 June 2021). Defense Primer: Emerging Technologies (PDF) (Report). Congressional Research Service. Retrieved 22 July 2021.
129. ^ Caitlin M Kenney One of Four Boosters Fails in Rapid-Fire Hypersonic Tests
130. ^ a b Oren Liebermann (21 October 2021, updated 22 Oct 21) Latest US military hypersonic test fails
131. ^ Mike Stone (29 Oct 2021) U.S. successfully tests hypersonic booster motor in Utah
132. ^ Mike Stone, Reuters (26 October 2022) Pentagon successfully flight tests hypersonic weapon components some 11 experiments: hypersonic communication and navigation equipment; materials that can withstand the atmospheric heating at hypersonic speeds
133. ^ Naval News Staff (28 October 2022) U.S. DoD Continues To Advance Hypersonic Capabilities
134. ^ US Department of Defense (28 Jun 2024) DOD Completes Flight Test of Hypersonic Missile
135. ^ a b c Mike Stone (27 Sep 2021) U.S. successfully flight tests Raytheon hypersonic weapon - Pentagon
* Theresa Hitchens (27 Sep 2021) DARPA Hypersonic Cruise Missile Prototype Flies At Last
136. ^ a b Aviation Week (30 Sep 2021) Raytheon Ends Air-Launched Hypersonic Vehicle Test Drought
137. ^ a b World'sTech "USAF Completes 1st Free Flight Test of HAWC Hypersonic Weapon..." - via www.youtube.com.
138. ^ a b Oren Liebermann (14 March 2022) US tested hypersonic missile in mid-March but kept it quiet to avoid escalating tensions with Russia Both the Raytheon and the Lockheed teams have now successfully tested their scramjets
139. ^ a b Alex Hollings (5 Apr 2022) US SUCCESSFULLY TESTS SCRAMJET-POWERED HYPERSONIC MISSILE IN SECRET "speeds just above Mach 5 at an altitude higher than 65,000 feet for more than 300 miles"
140. ^ a b Stephen Losey (22 Sep 2022) Raytheon wins $985M contract to develop hypersonic missile HACM possible fielding by FY2027
141. ^ a b Audrey Decker (28 Mar 2023) Failed Hypersonic Test Dims Air Force View of Lockheed Missile Air Force R&D funding for ARRW and HACM tests is $150 million and $380 million, respectively. "ARRW and HACM are just two of the U.S. military's hypersonic efforts; in all, the Pentagon is requesting $11 billion for hypersonic R&D in 2024"
142. ^ Passant Rabie (11 March 2024) Watch as World’s Largest Plane Releases Hypersonic Vehicle for Its First Powered Test Flight
143. ^ Mike Stone (11 March 2024) Hypersonic weapon startup Castelion has first prototype missile test
144. ^ Sydney Freedberg, Jr. Katz, Justin (24 March 2021). "OSD Writes Hypersonic Flight Test Guidelines".
145. ^ a b Theresa Hitchens Katz, Justin (22 March 2021). "DoD Needs To Sharpen Hypersonics Oversight: GAO".
146. ^ Nathan Strout (5 Oct 2020) SpaceX, L3 to provide hypersonic tracking satellites for Space Development Agency SDA's National Defense Space Architecture (NDSA)
147. ^ Courtney Albon (27 Oct 2022) Pentagon’s Shyu, LaPlante push to get critical tech into production "Senators may halve request for Rapid Defense Experimentation Reserve funding without transition plan" (RDER funding for DoD R&E, A&S projects)
148. ^ Joe Gould Gould, Joe (12 October 2021). "'Affordable' hypersonics, small business and sustainment lead DoD tech chief's priorities". Defense News.
149. ^ Tate Nurkin (9 Feb 2022) To catch China and Russia in hypersonic race, US must embrace risk now
150. ^ Courtney Albon (8 Nov 2022) Pentagon test bed to ramp up development of hypersonics MACH-TB
151. ^ Courtney Albon (6 Jan 2023) Pentagon racing to restore US superiority in hypersonics Test Resource Management Center (TRMC) SkyRange seeks to convert 24 Global Hawks for testing hypersonics.
152. ^ "Iran hypersonic missile claim sparks concern from UN nuclear watchdog". France 24. 10 November 2022. Retrieved 23 January 2023.
153. ^ "خبرگزاری فارس - سردار حاجی‌زاده: "کروز پاوه" در سبد موشکی سپاه قرار گرفت/ سرعت هایپرسونیک ایرانی ۱۳ ماخ است". خبرگزاری فارس. 24 February 2023.
154. ^ "U.S. Skeptical of Reports Iran Has Developed Hypersonic Missile -Pentagon".
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## Further reading

[edit]

* David Wright and Cameron Tracy, "Over-hyped: Physics dictates that hypersonic weapons cannot live up to the grand promises made on their behalf", Scientific American, vol. 325, no. 2 (August 2021), pp. 64–71. Quote from p. 71: "Failure to fully assess [the potential benefits and costs of hypersonic weapons] is a recipe for wasteful spending and increased global risk."

## External links

[edit]

Library resources about
Hypersonic flight

* * *

* Resources in your library
* Resources in other libraries

* A comparative analysis of the performance of long-range hypervelocity vehicles
* (2022) Joint Air Power Competence Centre (JAPCC)