View source for Physics:Hypersonic flight

{{Short description|Flight at altitudes lower than 90km and at speeds above Mach 5}}
'''Hypersonic flight''' is [[Physics:Flight|flight]] through the [[Astronomy:Atmosphere|atmosphere]] below altitudes of about 90&nbsp;km at [[Physics:Hypersonic speed|speeds greater than Mach 5]], a speed where [[Chemistry:Dissociation|dissociation]] of air begins to become significant and high heat loads exist. Speeds over Mach&nbsp;25 have been achieved below the [[Earth:Thermosphere|thermosphere]] as of 2020. 
[[File:General_Bernard_A._Schriever_ICBM_Test_Vehicle_USAF_1959.jpg|thumb|right|400px|Reentry vehicle (RV) after an {{convert|8000|km|adj=on}} 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.]]
{{Toclimit}}

==History==
The first manufactured object to achieve hypersonic flight was the two-stage Bumper rocket, consisting of a [[Engineering:WAC Corporal|WAC Corporal]] second stage set on top of a [[Engineering:V-2 rocket|V-2]] first stage. In February 1949, at White Sands, the rocket reached a speed of {{cvt|8290|km/h|mph|sigfig=3}}, or about Mach 6.7.<ref>{{cite web |url=https://airandspace.si.edu/collection-objects/missile-surface-surface-v-2-4 |first=Frank |last=Winter |title=V-2 missile |publisher=airandspace.si.edu |date=3 August 2000 |website=Smithsonian National Air and Space Museum |access-date=16 August 2018 |archive-date=4 January 2017 |archive-url=https://web.archive.org/web/20170104162919/https://airandspace.si.edu/collection-objects/missile-surface-surface-v-2-4 |url-status=dead }}</ref> The vehicle, however, burned on atmospheric re-entry, and only charred remnants were found. In April 1961, Russian Major [[Biography:Yuri Gagarin|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.<ref>[https://www.nasa.gov/topics/history/milestones/earthinspace.html Altitude reached: 116 miles, velocity reached: 5134 mph], or [https://www.grc.nasa.gov/WWW/k-12/airplane/mach.html Mach 8.5]</ref>

In November 1961, Air Force Major Robert White flew the X-15 research aircraft at speeds over Mach 6.<ref>{{cite web |last1=White |first1=Robert |title=Across the Hypersonic Divide |url=http://www.historynet.com/across-the-hypersonic-divide.htm |website=HistoryNet |publisher=HistoryNet LLC|access-date=11 October 2015}}</ref><ref>{{cite news |url=http://www.abc.net.au/news/stories/2010/03/22/2852999.htm?section=justin |title=Hypersonic plane passes latest test |publisher=ABC News (Australian Broadcasting Corporation) |date=22 March 2010 |access-date=18 February 2014}}</ref>
On 3 October 1967, in California, an X-15 reached Mach 6.7.<ref name= factsheet>{{Cite web |url=http://www.nasa.gov/centers/armstrong/news/FactSheets/FS-052-DFRC.html |title=NASA Dryden Fact Sheets - X-15 Hypersonic Research Program |first=Yvonne |last=Gibbs |date=13 August 2015 |website=NASA}}</ref>
 
The [[Astronomy:Atmospheric entry#Shock layer gas physics|reentry problem]] of a space vehicle was extensively studied.<ref name="naca1382">Alfred J. Eggers, H. Julian Allen, Stanford Neice (10 December 1954), [https://ntrs.nasa.gov/api/citations/19930093743/downloads/19930093743.pdf "A comparative analysis of the performance of long-range hypervelocity vehicles"], NACA report 1382, pp. 1141–1160</ref> The [[Engineering:NASA X-43|NASA X-43A]] flew on [[Astronomy:Scramjet|scramjet]] for 10 seconds, and then glided for 10 minutes on its last flight in 2004. The [[Engineering:Boeing X-51 Waverider|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 the United States, India, Russia, and China.<ref name="Xingkong2etc">In, for example [[Physics:Waverider|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

*[https://www.scmp.com/video/china/2158510/china-tests-hypersonic-aircraft-starry-sky-2 3 August 2018 China tests hypersonic aircraft Starry Sky-2] --Xingkong-2 (Starry-sky-2) first flight
*[https://timesofindia.indiatimes.com/world/china/china-successfully-tests-first-hypersonic-aircraft/articleshow/65290241.cms China successfully tests first hypersonic aircraft that can  .. ] [https://www.youtube.com/watch?v=zVXswjrRPyA Youtube clip XingKong-2 hypersonic aircraft (Starry Sky-2)]
*[https://www.cnbc.com/2018/08/07/us-nuclear-commander-russia-and-china-are-not-our-friends.html USSTRATCOM] John Hyten statement 05:03, 8 August 2018 (UTC)
*[https://www.youtube.com/watch?v=eHIXD7c8Lag (15 Jun 2018) Lockheed Martin Hypersonic Conventional Strike Weapon (HCSW) Missile for US Air Force]
**[https://www.defensenews.com/industry/techwatch/2019/12/17/lockheed-awards-815m-contract-for-hypersonic-missile-motor/ Chris Martin (17 Dec 2019) Lockheed awards $81.5M contract for hypersonic missile motor] to Rocketdyne for HCSW $81.5M, ARRW
*[https://www.npr.org/2018/10/23/659602274/amid-arms-race-fears-the-u-s-russia-and-china-are-racing-ahead-with-a-new-missil NPR (23 October 2018) Nations Rush Ahead With Hypersonic Weapons Amid Arms Race Fear ]
*[https://thehill.com/opinion/national-security/458769-putin-built-a-hypersonic-arsenal-while-the-pentagon-slept DOV S. ZAKHEIM, OPINION CONTRIBUTOR (08/26/19) Putin built a hypersonic arsenal, while the Pentagon slept]
*[https://breakingdefense.com/2019/06/raytheon-northrop-will-soon-fly-hypersonic-cruise-missile/ 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
*[https://indianexpress.com/article/india/india-test-fires-hypersonic-technology-demonstrator-vehicle-6586487/ DRDO successfully flight tests hypersonic technology vehicle] (September 7, 2020) Express News Service, The Indian Express

Current test targets, such as [https://www.army.mil/article/179788/us_army_announces_successful_test_of_us_army_zombie_pathfinder_rocket Zombie Pathfinder] are not hypersonic. [https://www.youtube.com/watch?v=FyUTNRIuAqc Rand Corporation (28 September 2017) Hypersonic Missile Nonproliferation] estimates there is less than a decade to prevent Hypersonic Missile proliferation.
</ref>

==Physics==
{{main|Physics:Hypersonic speed}}

=== Stagnation point ===
The [[Physics:Stagnation point|stagnation point]] of air flowing around a body is a point where its local velocity is zero.<ref name="naca1382" /> At this point the air flows around this location. A [[Physics:Shock wave|shock wave]] forms, which deflects the air from the stagnation point and insulates the flight body from the atmosphere.<ref name="naca1382" /> This can affect the lifting ability of a flight surface to counteract its drag and subsequent [[Physics:Free fall|free fall]].<ref>{{Cite web |url=https://web.mit.edu/16.unified/www/FALL/fluids/Lectures/f05.pdf |title=MIT "Fluids" 1. Effects of Reynolds Number 2. Effects of Mach Number|access-date=9 October 2020}}</ref>{{efn|name= ning|1= Ning describes a method for interrelating Reynolds number with Mach number.<ref>{{Cite web |url=http://flowlab.groups.et.byu.net/me412/hw/ReMmatching.pdf |title=Andrew Ning "Matching Mach and Reynolds Number"|access-date=9 October 2020}}</ref>}}

In order to maneuver in the atmosphere at faster speeds than supersonic, the forms of propulsion can still be airbreathing systems, but a [[Engineering:Ramjet|ramjet]] does not suffice for a system to attain Mach 5, as a ramjet slows down the airflow to subsonic.<ref name="Macias" /> Some systems ([[Physics:Waverider|waverider]]s) use a first stage rocket to boost a body into the hypersonic regime. Other systems ([[Astronomy:Boost-glide|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.<ref name= hvp >Jared Keller {{Cite web |url=https://taskandpurpose.com/news/air-force-hypervelocity-projectile-test-video/ |title=Watch the Air Force use a hypersonic bullet to blast a drone out of the sky |date=15 September 2020}}</ref>

===High temperature effect===

Hypersonic flow is a high energy flow.<ref name="Anderson">Anderson, John (2016). Introduction to Flight (Eighth ed.) McGraw-Hill Education</ref> 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 > 2000 K, dissociation of diatomic oxygen into oxygen radicals is active: O<sub>2</sub> → 2O<ref name= tableOfBDEs>B. deB. Darwent, National Bureau of Standards [https://nvlpubs.nist.gov/nistpubs/Legacy/NSRDS/nbsnsrds31.pdf (Jan 1970) Table of Bond Dissociation Energies in Simple Molecules] BDE: bond dissociation enthalpy</ref>{{rp|41}}<ref name= bondEnergies >Jim Clark (12 Feb 2022)[https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Thermodynamics/Energies_and_Potentials/Enthalpy/Bond_Enthalpies Physical and Theoretical Chemistry Textbook Maps/Supplemental Modules (Physical and Theoretical Chemistry)/Thermodynamics/Energies and_Potentials/Enthalpy/Bond Bond Enthalpies ]</ref><ref name= ronStackExch >Answered by ron, stack exchange [https://chemistry.stackexchange.com/questions/11173/will-heating-diatomic-oxygen-enough-break-the-o-o-bonds (29 May 2014) Will heating diatomic oxygen enough break the O=O bonds?]</ref> For T > 4000 K, dissociation of diatomic nitrogen into N radicals is active: N<sub>2</sub> → 2N<ref name= tableOfBDEs/>{{rp|39}} Consequently, in this temperature range, a plasma forms:<ref name= aPlasmaForms >Jan Tegler [https://issuu.com/faircountmedia/docs/defense-research-magazine/s/139231 (4 Oct 2019) Research at Hyper Speed: The Pentagon's Research Laboratories Are Working Flat Out to Develop Hypersonic Weapons Technology] operating at 8000 Kelvin</ref> —molecular dissociation followed by recombination of oxygen and nitrogen radicals produces nitric oxide: N<sub>2</sub> + O<sub>2</sub> → 2NO, which then dissociates and recombines to form ions: N + O → NO<sup>+</sup> + e<sup>−</sup><ref name= tableOfBDEs/>{{rp|39}} <ref name=lossOfTelemetry >Anthony Capaccio [https://www.bloomberg.com/news/articles/2023-03-28/lockheed-hypersonic-missile-test-marred-by-in-flight-data-loss?re_source=boa_related#xj4y7vzkg (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</ref>

===Low density flow===

At standard sea-level condition for air, the mean free path of air molecules is about <math>\lambda = 68 \,\mathrm{nm}</math>. Low density air is much thinner. At an altitude of {{cvt|342000|ft|km|order=flip}} the mean free path is <math>\lambda = 1 \, \mathrm{ft} = 0.305 \, \mathrm{m}</math>. 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]] <math>\mathrm{Kn}</math>, defined as <math>\mathrm{Kn}=\frac{\lambda}{l}</math> where <math>l</math> is the typical length scale of the object considered. The value of the Knudsen number based on nose radius, <math>\mathrm{Kn}=\frac{\lambda}{R}</math>, 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.<ref name="Anderson" />

===Thin shock layer===

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 <math>\mu = \sin^{-1} (a/v)</math> where a is the speed of the sound wave and v is the flow velocity. Since M=v/a, the equation becomes <math>\mu = \sin^{-1} (1/M)</math>. 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.<ref>{{cite web |date=6 April 2018 <!-- updated date, could change --> |title=Mach Angle |publisher=Glenn Research Center, NASA |url=https://www.grc.nasa.gov/WWW/K-12/airplane/machang.html}}</ref>

===Viscous interaction===

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.<ref name="Anderson" />

===Entropy layer===

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.<ref name="Anderson" />

==Propulsion==
=== Controlled detonation===
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.<ref name= contDetonMHD >Tim Newcomb [https://www.popularmechanics.com/military/weapons/a42778760/china-hypersonic-generator/ (6 Feb 2023) China Built a Hypersonic Generator That Could Power Unimaginable Weapons]</ref>

=== Rotating detonation===
A [[Physics:Rotating detonation engine|rotating detonation engine]] (RDE)<ref name= rtxRde >MRO Business Today [https://www.mrobusinesstoday.com/rtx-to-build-gambit-engine-for-darpa/ (9 Oct 2023) RTX to build Gambit engine for DARPA]; PRnewswire [https://www.rtx.com/news/news-center/2023/10/04/rtx-to-develop-rotating-detonation-engine-for-darpa (4 Oct 2023) RTX to develop rotating detonation engine for DARPA]</ref> 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/[[Astronomy:Scramjet|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.<ref name= geTbcc >Joseph Trevithic [https://www.thedrive.com/the-war-zone/ges-breakthrough-in-detonating-hypersonic-propulsion-is-a-big-deal (14 Dec 2023) GE's Breakthrough In 'Detonating' Hypersonic Propulsion Is A Big Deal]; GE Aerospace [https://www.geaerospace.com/press-release/other-news-information/ge-aerospace-demonstrates-hypersonic-dual-mode-ramjet-rotating (14 Dec 2023) GE Aerospace Demonstrates Hypersonic Dual-Mode Ramjet with Rotating Detonation Combustion]</ref>

==Applications==
=== Shipping ===
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.<ref name=":0" />

Stratolaunch Roc can be used to launch hypersonic aircraft.<ref name= roc >Camille Fine [https://www.usatoday.com/story/travel/airline-news/2023/01/20/worlds-largest-plane-hypersonic-vehicle-paul-allen/11091149002/ (20 Jan 2023) The biggest plane in the world has wings longer than a football field. See its latest flight]</ref>

[[Company:Hermeus|Hermeus]] demonstrated transition from turbojet aircraft engine operation to ramjet operation on 17 November 2022,<ref name=chimera >{{Cite web |title=Hermeus Completes Hypersonic Engine Milestone |url=https://www.hermeus.com/press-release-tbcc-milestone |access-date=2022-11-17 |website=Hermeus |language=en-US}}</ref> thus avoiding the need to boost aircraft velocities by rocket or scramjet.

{{anchor|Hypersonic weapons}}
:''See: [[Engineering:Lockheed Martin SR-72|SR-72]], § Mayhem''

=== Weapons ===
{{anchor|Hypersonic weapons development}}
{{anchor|Hypersonic Missile proliferation}}
{{anchor|NDSA}} 
{{Main|Engineering:Hypersonic weapon}} 
[[File:HypersonicFlight.jpg|thumb|right|Hypersonic weapon, demonstrating its [[Non-ballistic atmospheric entry|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.<ref name= tranch0 >[https://www.sda.mil/sda-awards-contracts-for-the-first-generation-of-the-tracking-layer/ C Todd Lopez (2 May 2021) On-Time Delivery Top Priority at Space Development Agency]</ref>

{{ulist
|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|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 [[Engineering:Hypersonic glide vehicle|hypersonic glide vehicle]]s.{{efn|name= 10ways| 1= "[N]on-nuclear capabilities may be able to complement nuclear forces in strategic deterrence plans"—The 2022 Nuclear Posture Review<ref name= ndsUnclNprMdr />{{rp|33rd-62nd pages}} as cited by Loren Thompson.<ref name= tenWays >Loren Thompson [https://www.forbes.com/sites/lorenthompson/2022/12/20/ten-ways-hypersonic-weapons-can-strengthen-strategic-deterrence/?sh=5ba0707573b8 (20 Dec 2022) Ten Ways Hypersonic Weapons Can Strengthen Strategic Deterrence]</ref> Thus non-nuclear hypersonics serve as  proportionate deterrent layers in the defense strategy of the United States.<ref name= ndsUnclNprMdr >Lloyd Austin III, US Secretary of Defense, et. al. [https://media.defense.gov/2022/Oct/27/2003103845/-1/-1/1/2022-NATIONAL-DEFENSE-STRATEGY-NPR-MDR.PDF (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)</ref> 
<ref name= ndsFact >US Department of Defense  [https://media.defense.gov/2022/Mar/28/2002964702/-1/-1/1/NDS-FACT-SHEET.PDF (28 Mar 2022) Fact Sheet: 2022 National Defense Strategy] 2 page sketch NDS</ref> 
<ref name= kahl2Hour >Colin Kahl, US Department of Defense [https://www.youtube.com/watch?v=dF8LxP8hPhw (4 Nov 2022) The 2022 National Defense Strategy: A conversation with Colin Kahl] 2 hour discussion of NDS presented by the Brookings Institution</ref>}}<ref name="urlfas.org">{{Cite web |url=https://fas.org/sgp/crs/weapons/R45811.pdf |title=Hypersonic Weapons: Background and Issues for Congress |publisher=Congressional Research Service}}</ref> Hypersonic weapons, by definition, travel five or more times the speed of sound. Hypersonic cruise missiles, which are powered by [[Astronomy:Scramjet|scramjet]]s, are limited to below {{convert|100,000|feet}};{{efn|name= asOf21Mar2022|1= According to Alex Hollings, as 21 March 2022 no nation has yet successfully fielded a [[Astronomy:Scramjet|scramjet]]-powered hypersonic cruise missile, including Russia's [[Engineering:3M22 Zircon|3M22 Zircon]].<ref name= notScramjet >Alex Hollings, Sandboxx [https://www.youtube.com/watch?v=rSPoF7IIefU (21 Mar 2022) Don't believe the hype around Russia's hypersonic Kinzhal missile] Kinzhal does not use a scramjet</ref>{{rp|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.<ref name= scramjetBasics >Alex Hollings [https://www.sandboxx.us/blog/america-may-have-just-taken-the-lead-in-hypersonic-cruise-missile-technology/ (7 Apr 2022) AMERICA MAY HAVE JUST TAKEN THE LEAD IN HYPERSONIC CRUISE MISSILE TECHNOLOGY] 2 tests of Hypersonic Air-breathing Weapon Concept (HAWC) using 2 different vendors</ref>}} 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.<ref name="Macias" /> 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.<ref name="Zastrow">Mark Zastrow (2021-11-04), [https://astronomy.com/news/2021/11/how-does-chinas-hypersonic-glide-vehicle-work "How does China's hypersonic glide vehicle work?"], Astronomy</ref>

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,<ref name=windTunnels >CNN [https://www.cnn.com/videos/world/2022/05/31/hypersonic-missiles-russia-china-us-warfare-technology-ebof-fisher-pkg-vpx.cnn (1 Jun 2022) Russia and China are ahead of US in hypersonic missile technology. Here's why]</ref><ref name=windTunnelLockheed >Valerie Insinna [https://breakingdefense.com/2022/06/lockheeds-ceo-wants-to-fund-a-hypersonic-wind-tunnel-but-says-dod-isnt-buying-in (2 Jun 2022) Lockheed’s CEO wants to fund a hypersonic wind tunnel, but says DoD isn’t buying in]</ref><ref>{{cite web |url=https://www.cnbc.com/2019/09/26/hypersonic-weapons-drive-arms-race-with-china-united-states-russia.html |title=Hypersonic weapons are the center of a new arms race between China, the US and Russia |first=Jeff Morganteen, Andrea |last=Miller |date=26 September 2019 |website=CNBC}}</ref><ref name="Xingkong2etc"/><ref name= hypersonicDefense >[https://www.upi.com/DARPA-issues-contract-proposition-for-hypersonic-missile-defense/4311542213243/ Stephen Carlson (14 Nov 2018) DARPA issues contract proposition for hypersonic missile defense]
*[https://www.upi.com/Space-lasers-hypersonic-missiles-rank-high-for-US-missile-defense-research/9611542126692/ Stephen Carlson (13 Nov 2018) Space, lasers, hypersonic missiles rank high for U.S. missile defense research]</ref> and in this case the problem is being addressed in a joint program of the entire Department of Defense.<ref name= ahwJointHypersonic >Sydney Freedberg, Jr.  {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2018/08/army-warhead-is-key-to-joint-hypersonics/ |title=Army Warhead Is Key To Joint Hypersonics |first=Justin |last=Katz |date=22 August 2018}}</ref> 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.{{refn|<ref name= navyTest2020Sched >[https://breakingdefense.com/2020/01/secnav-tells-fleet-hypersonic-competition-demands-sputnik-moment-glide-body-test-set/  Paul McLeary (31 January 2020) SecNav Tells Fleet Hypersonic Competition Demands ‘Sputnik Moment;’ Glide Body Test Set] Hypersonic Glide Body test for 2020</ref><ref name= 31may2019 >Sean Kimmons, Army News Service {{Cite web |url=https://www.army.mil/article/222617/joint_hypersonic_weapon_tests_to_start_next_year |title=Joint hypersonic weapon tests to start next year |website=www.army.mil}}</ref><ref name= thurgood2019 >Colin Clark  {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2019/05/army-moves-out-on-lasers-hypersonics-lt-gen-thurgood/ |title=Army Moves Out On Lasers, Hypersonics: Lt. Gen. Thurgood |date=24 May 2019}}</ref><ref name= helsLrhw2021 >[https://breakingdefense.com/2020/02/army-ramps-up-funding-for-laser-shield-hypersonic-sword/  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.</ref><ref name=glideBody /><ref name = R45811,24May2019 >[https://assets.documentcloud.org/documents/6189872/Hypersonic-Weapons-Background-and-Issues-for.pdf 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</ref><ref name = dyneticsChgbLockheedLrhw >[https://breakingdefense.com/2019/08/hypersonics-army-awards-699m-to-build-first-missiles-for-a-combat-unit/ 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)
*[https://www.army.mil/article/226368/army_awards_hypersonic_weapon_system_contracts Nancy Jones-Bonbrest, U.S. Army RCCTO (30 August 2019) Army awards hypersonic weapon system contracts]</ref>}}  India is also developing such weapons.<ref>{{Cite web |date=7 September 2020 |title=India successfully test-fires hypersonic missile carrier, 4th country to achieve the feat |url=https://theprint.in/defence/india-successfully-test-fires-hypersonic-missile-carrier-4th-country-to-achieve-the-feat/497491/|access-date=8 September 2020 |website=ThePrint}}</ref> France and Australia may also be pursuing the technology.<ref name="Macias" /> Japan is acquiring both scramjet (Hypersonic Cruise Missile), and boost-glide weapons (Hyper Velocity Gliding Projectile).<ref name= japan >{{cite web |url=https://www.defensenews.com/industry/techwatch/2020/03/13/japan-unveils-its-hypersonic-weapons-plans/ |title=Japan unveils its hypersonic weapons plans |first=Mike |last=Yeo |date=13 March 2020 |website=Defense News}}</ref>

==== China ====
China's XingKong-2 (星空二号, ''Starry-sky-2''), a [[Physics:Waverider|waverider]], had its first flight 3 August 2018.<ref>[https://www.scmp.com/video/china/2158510/china-tests-hypersonic-aircraft-starry-sky-2 "China tests waverider hypersonic aircraft Starry Sky-2"], 3 August 2018</ref><ref>{{cite news |url=https://timesofindia.indiatimes.com/world/china/china-successfully-tests-first-hypersonic-aircraft/articleshow/65290241.cms |title=China successfully tests first hypersonic aircraft that can carry nuclear warheads – Times of India |website=The Times of India|date=6 August 2018 }}</ref><ref>{{Cite web |url=https://www.youtube.com/watch?v=zVXswjrRPyA |title=Youtube clip XingKong-2 hypersonic aircraft (Starry Sky-2) |website=[[Company:YouTube|YouTube]]|access-date=9 October 2020}}</ref><ref name= jamestown >[https://jamestown.org/program/chinas-development-of-hypersonic-missiles-and-thought-on-hypersonic-defense/ 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."</ref>
{{anchor|aug2021FlightTest78}} 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.<ref name= fobs>Tyler Rogoway [https://www.thedrive.com/the-war-zone/42772/china-tested-a-fractional-orbital-bombardment-system-that-uses-a-hypersonic-glide-vehicle-report (16 Oct 2021)  China Tested A Fractional Orbital Bombardment System That Uses A Hypersonic Glide Vehicle: Report]</ref><ref>{{Cite news |url=https://www.reuters.com/world/china-surprises-us-with-hypersonic-missile-test-ft-reports-2021-10-17/ |title=China surprises U.S. with hypersonic missile test, FT reports |newspaper=Reuters |date=17 October 2021 |via=www.reuters.com}}</ref> However China has responded that the vehicle was a spacecraft, and not a missile;<ref name= ritchie>Hannah Ritchie, CNN [https://www.cnn.com/2021/10/18/china/china-hypersonic-missile-spacecraft-intl/index.html (18 October 2021) China denies testing a nuclear-capable hypersonic missile, says it was a spacecraft ]</ref> there was a July 2021 test of a spaceplane, according to Chinese Foreign Ministry Spokesperson Zhao Lijian;<ref name= hitchens19oct2021/><ref name= trevithick18oct2021>{{Cite web |url=https://www.thedrive.com/the-war-zone/42779/chinas-claim-that-its-fractional-orbital-bombardment-system-was-a-spaceplane-test-doesnt-add-up |title=China's Claim That Its Fractional Orbital Bombardment System Was A Spaceplane Test Doesn't Add Up (Updated) |first=Joseph |last=Trevithick |website=The Drive|date=18 October 2021 }}</ref><ref name= ft20Oct21>Demetri Sevastopulo, Washington [https://www.ft.com/content/c7139a23-1271-43ae-975b-9b632330130b (OCTOBER 20 2021) China conducted two hypersonic weapons tests this summer]</ref> 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).<ref name= hitchens19oct2021>{{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2021/10/questions-linger-over-chinas-reported-hypersonic-space-weapon-test/ |title=After China's 'Hypersonic' Test, US Alarm And Many Unanswered Questions |first=Theresa |last=Hitchens |date=19 October 2021}}</ref> 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;<ref name= fobs /> the second launch by China demonstrated its ability to change trajectories, according to Pentagon reports on the 2021 competition in arms capabilities.<ref name= 2ChineseLaunches >David E Sanger, and William J Broad ''The New York Times'' (28 Oct 2021) "China, Testing New Weapon, Jolts Pentagon"</ref>

In 2022 China unveiled two more hypersonic models.<ref name= 2pzd21 >Mike Yeo [https://www.defensenews.com/battlefield-tech/2022/11/10/china-shows-off-air-launched-hypersonic-missile-at-airshow-near-taiwan/ (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</ref><ref name= yj21 >Tanmay Kadam [https://eurasiantimes.com/china-finally-unveils-worlds-first-carrier-based-hypersonic/ (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".</ref> 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.<ref name= outrunIt >Stephen Chen, SCMP [https://www.scmp.com/news/china/science/article/3211730/chinese-ai-simulates-hypersonic-air-battle-offering-surprising-tactic-winning-mach-11-dogfight (28 Feb 2023) Chinese AI simulates hypersonic air battle, offering surprising tactic for winning Mach 11 dogfight]</ref> This strategy entails a fire control system to accomplish an over-the-shoulder missile launch, which does not yet exist (2023).<ref name= outrunIt />

In February 2023 the DF-27 covered 1200 miles in 12 minutes, according to leaked secret documents.<ref name=df27Feb2023 >Geoff Ziezulewicz [https://www.defensenews.com/news/your-navy/2023/04/18/pentagon-yes-we-are-still-lagging-behind-chinas-hypersonics/ (18 Apr 2023) Pentagon: Yes, we are still lagging behind China's hypersonics] DF-27</ref> The capability directly threatens Guam, and US Navy aircraft carriers.<ref name=df27Feb2023 />

==== Russia ====
In 2016, Russia is believed to have conducted two successful tests of [[Engineering:Avangard (hypersonic glide vehicle)|Avangard]], a hypersonic glide vehicle. The third known test, in 2017, failed.<ref>{{cite news |last1=Macias |first1=Amanda |title=The Kremlin says it conducted another successful test of a hypersonic weapon |url=https://www.cnbc.com/2018/12/26/the-kremlin-says-it-conducted-another-successful-test-of-a-hypersonic-weapon.html |publisher=CNBC |date=26 December 2018 |access-date=27 December 2018}}</ref> In 2018, an Avangard was launched at the Dombarovskiy missile base, reaching its target at the Kura shooting range, a distance of 3700 miles (5955&nbsp;km).<ref>[https://abcnews.go.com/beta-story-container/International/wireStory/russias-putin-oversees-test-hypersonic-weapon-60016274 "Putin crows as he oversees Russian hypersonic weapons test"], ABC News, 26 December 2018</ref>  Avangard uses new composite materials which are to withstand temperatures of up to 2,000 degrees Celsius (3,632 degrees Fahrenheit).<ref name="huff27dec2018" /> The Avangard's environment at hypersonic speeds reaches such temperatures.<ref name="huff27dec2018">[https://www.huffingtonpost.com/entry/hypersonic-nuclear-missile-russia_us_5c248de8e4b08aaf7a8dbc40 "Putin Says 'Invulnerable' New Hypersonic Nuclear Missile Is Ready For Deployment"], ''The Huffington Post'', 27 December 2018</ref> Russia considered its carbon fiber solution to be unreliable,<ref name="carbonFiber" /> and replaced it with new composite materials.<ref name="huff27dec2018" /> Two Avangard hypersonic glide vehicles (HGVs)<ref name= diplomat/> 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.<ref>Vladimir Isachenkov (27 December 2019) [https://apnews.com/597e7f2b20b21af959e4c6983b255c37 "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 —{{cite news |date=27 December 2019 |script-title=ru:На боевое дежурство заступил первый полк с "Авангардами" |language=RU |title=The first regiment with the 'Avangard' took up combat duty |publisher=Interfax |url=https://www.interfax.ru/russia/689653}}
*[https://www.nbcnews.com/news/world/russia-commissions-intercontinental-hypersonic-weapon-n1107741 "Russia commissions intercontinental hypersonic weapon"], NBC News, Associated Press, 27 December 2019.</ref> In an earlier report, Franz-Stefan Gady named the unit as the 13th Regiment/Dombarovskiy Division (Strategic Missile Force).<ref name= diplomat >[https://thediplomat.com/2019/11/russia-avangard-hypersonic-warhead-to-enter-service-in-coming-weeks/ 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.</ref>
In 2021 Russia launched a [[Engineering:3M22 Zircon|3M22 Zircon]] antiship missile over the White Sea, as part of a series of tests.<ref name= whiteSea>AP [https://www.defensenews.com/training-sim/2021/11/29/russian-navy-test-fires-hypersonic-missile-in-the-white-sea/ (29 Nov 2021) Russian Navy test-fires hypersonic missile in the White Sea]</ref> "[[Engineering:Kh-47M2 Kinzhal|Kinzhal]] and [[Engineering:3M22 Zircon|Zircon]] (Tsirkon) are standoff strike weapons".<ref name= 7feb2022rcd >Roger McDermott [https://www.realcleardefense.com/articles/2022/02/07/the_role_of_hypersonic_weapons_in_russian_military_strategy_815512.html (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,</ref> In February 2022, a coordinated series of missile exercises, some of them hypersonic, were launched on 18 February 2022 in an apparent display of [[Social:Power projection|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, and flown across Northern Russia, to land on the Kamchatka peninsula.<ref name= 18feb2022 >CNN [https://www.cnn.com/europe/live-news/ukraine-russia-news-02-19-22-intl/h_672cdcbb430f235abd3705d642b56b3b (19 Feb 2022) ]</ref>

==== United States ====
These tests have prompted US responses in weapons development.<ref name= pNanda >Prakash Nanda, ''Eurasian Times'' [https://eurasiantimes.com/why-is-the-us-still-unable-to-develop-hypersonic-weapons/ (6 Nov 2022) Hypersonic Hype? This Is Why US 'Trails' Russia, China & Even North Korea In Hypersonic Missile Development]</ref> By 2018, the AGM-183<ref name= 480million>[https://www.cnbc.com/2018/08/14/lockheed-martin-gets-480-million-hypersonics-contract-from-pentagon.html "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</ref> and Long-Range Hypersonic Weapon<ref name= noRepeat/> were in development per John Hyten's USSTRATCOM statement on 8 August 2018 (UTC).<ref name="hyten">
[https://www.cnbc.com/2018/08/07/us-nuclear-commander-russia-and-china-are-not-our-friends.html USSTRATCOM], CNBC</ref> At least one vendor is developing ceramics to handle the temperatures of hypersonics systems.<ref name="wired27dec2018">Nick Stockton (27 December 2018), [https://www.wired.com/story/rotating-detonation-engine/ "Rotating Detonation Engines Could Propel Hypersonic Flight"], ''Wired''</ref> There are over a dozen US hypersonics projects as of 2018, notes the commander of USSTRATCOM;<ref name="hyten" /><ref name= hyten28Oct2021>Colin Clark [https://breakingdefense.com/2021/10/hundreds-of-china-hypersonic-tests-vs-9-us-hyten-says-us-moves-too-slowly/ (28 Oct 2021) 'Hundreds' Of China Hypersonic Tests Vs. 9 US; Hyten Says US Moves Too Slowly]</ref><ref name= noRepeat>Sydney Freedberg (13 March 2019), [https://breakingdefense.com/2019/03/hypersonics-wont-repeat-mistakes-of-f-35/ "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)"
</ref><ref name= glideBreaker >Joseph Trevithick (6 September 2018), [http://www.thedrive.com/the-war-zone/23398/darpa-starts-work-on-glide-breaker-hypersonic-weapons-defense-project "DARPA Starts Work On 'Glide Breaker' Hypersonic Weapons Defense Project"], The Drive
</ref><ref name= geopolitics >[https://www.defenseone.com/technology/2020/01/us-aims-intimidate-china-hypersonics-once-it-solves-physics/162408/ Patrick Tucker (13 January 2020) The US Wants to Intimidate China with Hypersonics, Once It Solves the Physics] 2020 review</ref><ref name= darpaTunnel >Joseph Trevithic (6 August 2019), [https://www.thedrive.com/the-war-zone/29307/air-force-reveals-tests-of-supposed-record-setting-scramjet-engine-from-northrop-grumman "Air Force Reveals Tests Of Supposed Record-Setting Scramjet Engine From Northrop Grumman"]</ref> from which a future hypersonic cruise missile is sought, perhaps by Q4 FY2021.<ref name= usafPdrQ4FY2021 >{{Cite web |url=https://www.flightglobal.com/fixed-wing/us-air-force-launches-study-of-another-hypersonic-cruise-missile/138151.article |title=US Air Force launches study of another hypersonic cruise missile |first=Garrett |last=Reim2020-04-30T00:42:00+01:00 |website=Flight Global|access-date=9 October 2020}}</ref><ref name= kendall >THERESA HITCHENS and AARON MEHTA {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2021/09/as-air-force-signals-hypersonic-doubts-key-senators-want-to-go-faster/ |title=As Air Force Signals Hypersonic Doubts, Key Senators Want To Go Faster |date=24 September 2021}}</ref><ref name="3rdFailure">Valerie Insinna [https://breakingdefense.com/2021/12/air-force-hypersonic-weapon-runs-into-trouble-after-a-third-failed-test/ (20 Dec 2021) Air Force hypersonic weapon runs into trouble after a third failed test]</ref> The Long range precision fires (LRPF) CFT is supporting Space and Missile Defense Command's pursuit of hypersonics.{{refn|<ref name=glideBody >Joe Lacdan {{Cite web |url=https://www.army.mil/article/212487/the_army_joins_the_air_force_navy_in_attempt_to_develop_hypersonic_weaponry |title=The Army joins the Air Force, Navy in attempt to develop hypersonic weaponry |website=www.army.mil}}</ref><ref name=armyHypersonics2019 >[https://www.army.mil/article/217024/experiments_in_hyperspeed Mary Kate Aylward (5 February 2019) Experiments in hyperspeed] more on Prompt Global Strike</ref><ref name= promptConventionalStrike >[https://news.usni.org/2017/11/03/navy-conducts-flight-test-support-conventional-prompt-strike-ohio-class-boomers 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)</ref>}}  Joint programs in hypersonics are informed by Army work;<ref <ref name= 15Aug2018 >{{Cite web |url=https://www.army.mil/article/209932/army_futures_command_aims_to_tap_into_innovative_culture_in_austin_and_beyond |title=Army Futures Command aims to tap into innovative culture in Austin and beyond |website=www.army.mil}}</ref><ref name=lprf210198 /> however, at the strategic level, the bulk of the hypersonics work remains at the Joint level.{{refn|<ref name = wp2aug19 >[https://www.washingtonpost.com/business/2019/08/02/conversations-with-investors-defense-firms-double-down-hypersonic-weapons 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.</ref><ref name = dodBoosts136percent >Sydney J. Freedberg Jr. {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2018/03/dod-boosts-hypersonics-136-in-2019-darpa/ |title=DoD Boosts Hypersonics 136 % In 2019: DARPA |first=Justin |last=Katz |date=1 March 2018}}</ref><ref name= "secNavy, amc, smdc" >[https://www.army.mil/article/211330/secretary_of_the_navy_visits_amc_smdc Jason Cutshaw (19 September 2018) Secretary of the Navy visits AMC, SMDC] memorandum of agreement in June to co-develop a hypersonic vehicle</ref><ref name=dodBillionsOnHypersonicWeapons /><ref name=dyneticsChgbLockheedLrhw/>}} Long Range Precision Fires (LRPF) is an Army priority, and also a DoD joint effort.<ref name= lprf210198 >{{Cite web |url=https://www.army.mil/article/210198/long_range_precision_fires_modernization_a_joint_effort_army_tech_leader_says |title=Long-range precision fires modernization a joint effort, Army tech leader says |website=www.army.mil}}</ref> The Army and Navy's Common Hypersonic Glide Body (C-HGB) had a successful test of a prototype in March 2020.<ref name="chgbTest20Mar20" >[https://breakingdefense.com/2020/03/hypersonics-army-navy-test-common-glide-body/ 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"
*[https://www.army.mil/article/233873/department_of_defense_tests_hypersonic_glide_body 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</ref><ref name=dodBillionsOnHypersonicWeapons >[https://www.nationaldefensemagazine.org/articles/2020/3/4/pentagon-to-spend-billions-mass-producing-hypersonic-weapons 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"</ref> A wind tunnel for testing hypersonic vehicles will be built in Texas (2019).<ref name = hypersonicWindTunnelA&M >Haley Britzky  {{Cite web |url=https://taskandpurpose.com/news/army-futures-command-texas/ |title=The Army is getting a new $130 million hypersonics playground in Texas |date=14 August 2019}}</ref> The Army's Land-based Hypersonic Missile "is intended to have a range of {{convert|1,400|miles}}".<ref name=R45811 />{{rp|p.6}} <ref name=dyneticsChgbLockheedLrhw/><ref name= shyu >Justin Katz [https://breakingdefense.com/2022/02/pentagon-developing-national-defense-science-and-technology-strategy-memo/ (2 Feb 2022) Pentagon developing ‘National Defense Science and Technology’ strategy: Memo] 14 technologies</ref><ref name= 14technologies >Brandi Vincent [https://www.defenseone.com/technology/2022/02/defense-department-previews-new-future-facing-technology-aims/361598/ (4 Feb 2022) Pentagon Previews New Tech Strategy, Updates Priorities List] for upcoming National Defense Science and Technology Strategy</ref><ref name= meetingWithIndustry>Courtney Albon and Joe Gould [https://www.defensenews.com/industry/2022/02/04/top-pentagon-officials-met-with-industry-executives-about-hypersonics-what-comes-next/ (4 Feb 2022) Top Pentagon officials met with industry executives about hypersonics. What comes next?] a range of concerns</ref><ref name= usniNews >Naval News Staff [https://www.navalnews.com/naval-news/2022/11/hypersonic-missiles-evolution-or-revolution/ (1 Nov 2022) Hypersonic Missiles: Evolution Or Revolution? ] summary overview</ref> 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.<ref name= jointCollaboration2019 >Gary Sheftick {{Cite web |url=https://www.army.mil/article/217305/army_aligning_modernization_programs_with_other_services |title=Army aligning modernization programs with other services |website=www.army.mil}}</ref><ref name= mdo,1000miTargeting >[https://breakingdefense.com/2018/09/aiming-the-armys-thousand-mile-missiles/  Sydney J. Freedberg Jr. (11 September 2018) Aiming The Army's Thousand-Mile Missiles] Multi-domain Ft Sill</ref> 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.{{refn|<ref name = hbtss >John L. Dolan, Richard K. Gallagher & David L. Mann [https://www.realcleardefense.com/articles/2019/04/23/hypersonic_weapons__a_threat_to_national_security_114358.html (23 April 2019) Hypersonic Weapons – A Threat to National Security] Hypersonic and Ballistic Tracking Space Sensor (HBTSS)
*[https://defensemaven.io/warriormaven/air/pentagon-advances-new-technology-to-destroy-hypersonic-missile-attacks-oKccmcWHpkqQhBTN-RLtJg/ Kris Osborn (16 December 2019) Pentagon Advances New Technology to Destroy Hypersonic Missile Attacks] HBTSS will "establish a continuous 'track' on approaching hypersonic missiles"
*[https://www.c4isrnet.com/space/2020/04/08/three-obstacles-are-slowing-space-sensors-for-hypersonic-threats/ 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.
*[https://www.newsweek.com/pentagon-orders-hypersonic-missile-trackers-russia-china-arms-race-1564754 David Brennan (27 Jan 2021) Pentagon Orders Hypersonic Missile Trackers Amid Russia, China Arms Race] HBTSS awards to L3Harris; Northrop Grumman</ref><ref name= opirFunding >[https://breakingdefense.com/2020/02/2021-budget-will-finally-fully-fund-next-gen-opir-says-roper/ Theresa Hitchens (24 February 2020) 2021 Budget Will Finally Fully Fund Next-Gen OPIR, Says Roper ] [[Engineering:Space-Based Infrared System|Space-Based Infrared System (SBIRS)]] replacement: three satellites in Geosynchronous Orbit (GEO) and two satellites in a polar orbit</ref><ref name = mdaCapability >[https://www.defensenews.com/pentagon/2019/08/19/us-missile-defense-agency-boss-reveals-his-goals-challenges-on-the-job/ 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).</ref><ref name= l3Harris >Theresa Hitchens {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2020/10/sda-missile-tracking-a-strategic-win-for-l3harris-spacex/ |title=SDA Missile Tracking A 'Strategic Win' For L3Harris, SpaceX |first=Justin |last=Katz |date=9 October 2020}}</ref>}} There are also privately developed hypersonic systems,<ref>Colin Clark (19 June 2019), [https://breakingdefense.com/2019/06/raytheon-northrop-will-soon-fly-hypersonic-cruise-missile/ "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.</ref> as well as critics.<ref name= bugosAca >Shannon Bugos  {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2021/09/congress-shouldnt-rubber-stamp-hypersonic-weapons/ |title=Congress Shouldn't Rubber-Stamp Hypersonic Weapons |first=Justin |last=Katz |date=29 September 2021}}</ref><ref name= talonStratolaunch >Ashish Dangwal {{Cite web |url=https://eurasiantimes.com/hypersonic-missiles-us-draws-big-plan-to-engage-intercept-shoot-down-china/ |title=Hypersonic Missiles: US Draws Big Plan To Track, Intercept & Shoot-Down Chinese Super-Maneuverable Threats |date=10 December 2021 |website=Latest Asian, Middle-East, EurAsian, Indian News}}</ref>

DoD tested a Common Hypersonic Glide Body (C-HGB) in 2020.<ref name="chgbTest20Mar20" /><ref name= 4testsScheduledIn2020 >{{cite web |url=https://www.nationaldefensemagazine.org/articles/2020/3/2/pentagon-to-testfly-new-hypersonic-weapon-this-year |title=Pentagon to TestFly New Hypersonic Weapon This Year |website=www.nationaldefensemagazine.org}}</ref> The Air Force dropped out of the tri-service hypersonic project in 2020, leaving only the Army and Navy on the C-HGB.<ref name= usRunningWrongWay >[https://www.realcleardefense.com/articles/2020/04/21/dod_is_running_the_wrong_way_in_the_hypersonics_race_115218.html Bryan Clark (21 April 2020) DoD Is Running the Wrong Way in the Hypersonics Race] 500 pound payload; maneuverability at Mach 5 is an issue; possible red herring for funding</ref><ref name= afBails >JOSEPH TREVITHICK {{Cite web |url=https://www.thedrive.com/the-war-zone/32156/air-force-bails-on-tri-service-hypersonic-weapon-project-as-army-navy-ask-for-more-money |title=Air Force Bails On Tri-Service Hypersonic Weapon Project As Army, Navy Ask For More Money |first=Joseph |last=Trevithick |website=The Drive|date=11 February 2020 }}</ref><ref name="hcsw">{{Cite web |url=https://www.youtube.com/watch?v=eHIXD7c8Lag |title=Lockheed Martin Hypersonic Conventional Strike Weapon (HCSW) Missile for US Air Force |website=[[Company:YouTube|YouTube]]|access-date=9 October 2020}} $928 million</ref>
According to Air Force chief scientist, Dr. Greg Zacharias, the US anticipates having hypersonic weapons by the 2020s,<ref>Sean Kimmons (31 May 2019), [https://www.army.mil/article/222617/joint_hypersonic_weapon_tests_to_start_next_year "Joint hypersonic weapon tests to start next year"], Army News Service</ref> hypersonic drones by the 2030s, and recoverable hypersonic drone aircraft by the 2040s.<ref>{{cite web |url=http://nationalinterest.org/blog/the-buzz/get-ready-russia-china-americas-next-fighter-jet-will-21876 |title=Get Ready, Russia and China: America's Next Fighter Jet Will Dominate the Skies |first=Kris |last=Osborn |date=12 August 2017 |website=The National Interest|access-date=2 March 2018}}</ref> The focus of DoD development will be on air-breathing [[Astronomy:Boost-glide|boost-glide]] hypersonics systems.<ref name="Vergun">David Vergun (14 December 2018), [https://www.army.mil/article/215126/dod_scaling_up_effort_to_develop_hypersonics "DOD scaling up effort to develop hypersonics"], U.S. Army</ref> 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.<ref name="Vergun" /><ref>Loren Thompson (30 July 2019) [https://www.forbes.com/sites/lorenthompson/2019/07/30/defense-against-hypersonic-attack-is-becoming-the-biggest-military-challenge-of-the-trump-era/#446b77d062c0 "Defense Against Hypersonic Attack Is Becoming The Biggest Military Challenge Of The Trump Era"]</ref><ref name= hbtss/><ref>Paul McLeary (18 December 2019), [https://breakingdefense.com/2019/12/mda-kickstarts-new-way-to-kill-hypersonic-missiles/ "MDA Kickstarts New Way To Kill Hypersonic Missiles"] MDA's Hypersonic Defense Weapon System – 4 Interceptors</ref> A mid-2021 report from the [[Social:Congressional Research Service|Congressional Research Service]] states the United States is "unlikely" to field an operational hypersonic glide vehicle (HGV) until 2023.<ref name=CRS1>{{cite report |author=Kelley M. Sayler |date=June 8, 2021 |title=Defense Primer: Emerging Technologies |url=https://fas.org/sgp/crs/natsec/IF11105.pdf |publisher=[[Social:Congressional Research Service|Congressional Research Service]] |access-date=July 22, 2021}}</ref>
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.<ref name= sandiaCampaign>Caitlin M Kenney [https://www.defenseone.com/technology/2021/10/one-four-boosters-fails-rapid-fire-hypersonic-tests/186303/ One of Four Boosters Fails in Rapid-Fire Hypersonic Tests]</ref> The test occurred at Pacific Spaceport Complex – Alaska, on Kodiak island.<ref name= kodiak,2021,10,21>Oren Liebermann [https://www.cnn.com/2021/10/21/politics/us-hypersonic-test-fails/index.html (21 October 2021, updated 22 Oct 21) Latest US military hypersonic test fails]</ref> Three [[Earth:Rocketsonde|rocketsonde]]s at Wallops Island completed successful tests earlier that week, for the hypersonics effort.<ref name= kodiak,2021,10,21 /> 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.<ref name= lrhwStaticTest>Mike Stone [https://news.yahoo.com/u-successfully-tests-hypersonic-booster-153513394.html (29 Oct 2021) U.S. successfully tests hypersonic booster motor in Utah]</ref> On 26 October 2022 Sandia National Laboratories conducted a successful test of hypersonic technologies at Wallops Island.<ref name= 11tests >Mike Stone, Reuters [https://www.reuters.com/world/us/pentagon-successfully-flight-tests-hypersonic-weapon-components-2022-10-26/ (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</ref><ref name = sspAhpo >Naval News Staff  [https://www.navalnews.com/naval-news/2022/10/u-s-dod-continues-to-advance-hypersonic-capabilities/ (28 October 2022) U.S. DoD Continues To Advance Hypersonic Capabilities]</ref>

In September 2021, and in March 2022, US vendors Raytheon/Northrop Grumman,<ref name= hawcTest2021/><ref name= hawc30Sep2021/><ref name= hawcVideo/> and Lockheed<ref name= hawcMidMarch22/><ref name= hollings/> respectively, first successfully tested their air-launched, scramjet-powered hypersonic cruise missiles, which were funded by DARPA.{{efn|name= asOf21Mar2022}} By September 2022 Raytheon was selected for fielding Hypersonic Attack Cruise Missile (HACM), a scramjet-powered hypersonic missile by FY2027.<ref name=hacmScifire /><ref name=failedArrwTest >Audrey Decker [https://www.defenseone.com/technology/2023/03/failed-hypersonic-test-dims-air-force-view-lockheed-missile/384530/ (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"</ref>

=== Iran ===
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"<ref>{{Cite web |date=2022-11-10 |title=Iran hypersonic missile claim sparks concern from UN nuclear watchdog |url=https://www.france24.com/en/middle-east/20221110-iran-hypersonic-missile-claim-sparks-concern-from-un-nuclear-watchdog |access-date=2023-01-23 |website=France 24 |language=en}}</ref> and has a speed above Mach 13.<ref>{{Cite web |title=Iranian hypersonic speed is Mach 13 |url=https://www.farsnews.ir/news/14011205000663/%D8%B3%D8%B1%D8%AF%D8%A7%D8%B1-%D8%AD%D8%A7%D8%AC%DB%8C%E2%80%8C%D8%B2%D8%A7%D8%AF%D9%87-%DA%A9%D8%B1%D9%88%D8%B2-%D9%BE%D8%A7%D9%88%D9%87-%D8%AF%D8%B1-%D8%B3%D8%A8%D8%AF-%D9%85%D9%88%D8%B4%DA%A9%DB%8C-%D8%B3%D9%BE%D8%A7%D9%87-%D9%82%D8%B1%D8%A7%D8%B1-%DA%AF%D8%B1%D9%81%D8%AA-%D8%B3%D8%B1%D8%B9%D8%AA}}</ref> but Col. Rob Lodwick, the spokesman for the Pentagon on Middle East affairs said that there are doubts in this regard.<ref>{{Cite web |title=U.S. Skeptical of Reports Iran Has Developed Hypersonic Missile -Pentagon |url=https://www.usnews.com/news/world/articles/2022-11-17/u-s-skeptical-of-reports-iran-has-developed-hypersonic-missile-pentagon}}</ref>
;Rand 2017 assessment{{anchor|Hypersonic defense}}
Rand Corporation (28 September 2017) estimates there is less than a decade to prevent Hypersonic Missile proliferation.<ref>[https://www.youtube.com/watch?v=FyUTNRIuAqc "Hypersonic Missile Nonproliferation"], Rand Corporation, 28 September 2017, via YouTube</ref> 
In the same way that [[Engineering:Anti-ballistic missile|anti-ballistic missile]]s were developed as countermeasures to [[Physics:Ballistic missile|ballistic missile]]s, counter-countermeasures to [[Physics:Hypersonic|hypersonic]]s systems were not yet in development, as of 2019.<ref name="Macias">Amanda Macias (21 March 2018), [https://www.cnbc.com/2018/03/21/hypersonic-weapons-what-they-are-and-why-us-cant-defend-against-them.html "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
</ref><ref name="n852211">Arie Egozi  {{cite news |url=https://www.nbcnews.com/news/world/vladimir-putin-set-state-union-speech-election-looms-n852211 |title=Putin unveils new nuclear missile, says 'listen to us now' |website=nbcnews.com|access-date=2 March 2018}}</ref><ref name="carbonFiber">Amanda Macias (12 October 2018), [https://www.cnbc.com/2018/10/12/russia-having-trouble-building-hypersonic-weapon-putin-hyped.html "Russia hits a snag in developing a hypersonic weapon after Putin said it was already in production"], CNBC</ref><ref name= summarySydney >Sydney Freedberg (1 February 2019) [https://breakingdefense.com/2019/02/pentagon-studies-post-inf-weapons-shooting-down-hypersonics/ "Pentagon Studies Post-INF Weapons, Shooting Down Hypersonics"], Breaking Defense</ref> ''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.<ref name="R45811">Kelley M. Sayler (11 July 2019), [https://assets.documentcloud.org/documents/6189872/Hypersonic-Weapons-Background-and-Issues-for.pdf "Hypersonic Weapons: Background and Issues for Congress"], Congressional Research Service</ref> $207 million of the FY2021 budget was allocated to defensive hypersonics, up from the FY2020 budget allocation of $157 million.<ref name="gaoOnHypersonics" >Theresa Hitchens {{Cite web |url=https://breakingdefense.sites.breakingmedia.com/2021/03/dod-needs-to-sharpen-hypersonics-oversight-gao/ |title=DoD Needs To Sharpen Hypersonics Oversight: GAO |first=Justin |last=Katz |date=22 March 2021}}</ref><ref name= gao21-378>[[Engineering:Government Accountability Office|Government Accountability Office]] [https://www.gao.gov/assets/gao-21-378.pdf (Mar 2021) Hypersonic Weapons] DOD Should Clarify Roles and Responsibilities to Ensure Coordination across Development Efforts, recommendation gao-21-378</ref><ref name = R45811,24May2019 /> 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,<ref>Linda Givetash (2 February 2019), [https://www.nbcnews.com/news/world/putin-says-russia-also-suspending-key-nuclear-arms-treaty-response-n966146 "Putin says Russia also suspending key nuclear arms treaty after U.S. move to withdraw", NBC News, Reuters]</ref><ref>Rebecca Kheel and Morgan Chalfant (31 July 2019) [https://thehill.com/policy/defense/455437-landmark-us-russia-arms-control-treaty-poised-for-final-blow "Landmark US-Russia arms control treaty poised for final blow"], ''The Hill''</ref> in FY2021 and forward.<ref name= lrhwChgbTbgHswab >[https://www.forbes.com/sites/sebastienroblin/2020/04/30/the-pentagons-plans-to-deploy-an-arsenal-of-hypersonic-weapons-in-the-2020s/#614b5a0c3a5d Sebastien Roblin (30 April 2020) The Pentagon Plans to Deploy An Arsenal Of Hypersonic Weapons In The 2020s] Army LRHW, Navy C-HGB, Air Force HSW-ab</ref> By 2021 the Missile Defense Agency was funding regional countermeasures against hypersonic weapons in their glide phase.<ref name= mdaHbtss >{{Cite web |url=https://www.defensenews.com/digital-show-dailies/smd/2021/08/13/missile-defense-agency-dials-up-the-speed-in-quest-for-hypersonic-interceptor/ |title=Missile Defense Agency dials up the speed in quest for hypersonic interceptor |first=Jen |last=Judson |date=13 August 2021 |website=Defense News}}</ref><ref name= gpiDownselect >[https://breakingdefense.com/2021/08/next-budget-will-limit-glide-phase-interceptor-contractors-mda-head/ Theresa Hitchens (12 Aug 2021) Next Budget Will Limit Glide Phase Interceptor Contractors: MDA Head] 2028 target date is being accelerated. FY2022 decisions on GPI/[[Engineering:Ground-Based Interceptor|Ground-Based Interceptor]], GBI replacement (the Next generation interceptor NGI) will be made by Deputy Secretary Kathleen Hicks.</ref><ref name= mdaVideoJun2021 >[https://www.thedrive.com/the-war-zone/41164/missile-defense-agency-lays-out-how-it-plans-to-defend-against-hypersonic-threats BRETT TINGLEY AND JOSEPH TREVITHICK (19 JUNE 2021) Missile Defense Agency Lays Out How It Plans To Defend Against Hypersonic Threats]
*[https://www.youtube.com/watch?v=-q-ieXZgrhY Missile Defense Agency (16 Jun 2021) MDA Concept for Regional Hypersonic Missile Defense: Technology to Defeat the Threat] GPI scenario animation 7:51</ref> 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.<ref name= flight78>[https://www.npr.org/2021/10/20/1047384050/behind-murky-claim-of-a-new-hypersonic-missile-test-there-lies-a-very-real-arms- Jeff Brumfiel (20 Oct 2021) Behind murky claim of a new hypersonic missile test, there lies a very real arms race] Michael Griffin comments</ref> Doug Loverro assesses that both missile defense and [[Philosophy:Conflict continuum#Competition continuum|competition]] need rethinking.<ref name= loverro >Theresa Hitchens [https://breakingdefense.com/2021/10/hypersonic-space-test-fuels-sino-american-arms-race/ (21 Oct 2021) Hypersonic Space Test Fuels Sino-American Arms Race]</ref> CSIS assesses that hypersonic defense should be the US' priority over hypersonic weapons.<ref name= csis7Feb22 >Center for Strategic & International Studies [https://www.youtube.com/watch?v=Tn-C4uMWnyY (7 Feb 2022) Complex Air Defense: Countering the Hypersonic Missile Threat] Dr. Tom Karako, Director of the CSIS Missile Defense Project; Ms. Kelley Sayler, CRS; Dr. Gillian Bussey, Director of the Joint Hypersonics Transition Office;  Dr. Mark Lewis, Executive Director of NDIA's Emerging Technologies Institute;  Mr. Stan Stafira, Chief Architect at the Missile Defense Agency (MDA)</ref>{{efn|name=Sayler'sSummary|1= 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.<ref name= csis7Feb22/>{{rp|min 19:00–21:00}}<ref name= hypersonicsDefense/> }}<ref name= hypersonicsDefense >Theresa Hitchens [https://breakingdefense.com/2022/02/pentagon-needs-to-prioritize-hypersonic-defense-not-offense-csis/ (7 Feb 2022) Pentagon needs to prioritize hypersonic defense, not offense: CSIS]</ref><ref name= IF11623 >Congressional Research Service [https://sgp.fas.org/crs/weapons/IF11623.pdf (2 May 2023) Hypersonic Missile Defense: Issues for Congress] IF11623</ref>

In 2021, DoD was codifying flight test guidelines, knowledge gained from Conventional Prompt Strike (CPS) and the other hypersonics programs,<ref name= fromLabsToScale >Sydney Freedberg, Jr.  {{Cite web |url=https://breakingdefense.com/2021/03/osd-writes-hypersonic-flight-test-guidelines/ |title=OSD Writes Hypersonic Flight Test Guidelines |first=Justin |last=Katz |date=24 March 2021}}</ref> for some 70 hypersonics R&D programs alone, as of 2021.<ref name="gaoOnHypersonics" /><ref name= ndsa >[https://www.c4isrnet.com/battlefield-tech/space/2020/10/05/space-development-agency-orders-8-hypersonic-weapon-tracking-satellites/ Nathan Strout (5 Oct 2020) SpaceX, L3 to provide hypersonic tracking satellites for Space Development Agency] SDA's National Defense Space Architecture ([[Physics:Hypersonic flight#Hypersonic weapons development|NDSA]])</ref> In 2021-2023, Heidi Shyu, the Under Secretary of Defense for Research and Engineering (USD(R&E)) is pursuing a program of annual rapid joint experiments,<ref name= shyuLaPlante >Courtney Albon [https://www.c4isrnet.com/battlefield-tech/2022/10/27/pentagons-shyu-laplante-push-to-get-critical-tech-into-production/ (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)</ref> including hypersonics capabilities, to bring down their cost of development.<ref>Joe Gould  {{Cite web |url=https://www.defensenews.com/digital-show-dailies/ausa/2021/10/12/affordable-hypersonics-small-business-and-sustainment-lead-dod-tech-chiefs-priorities/ |title='Affordable' hypersonics, small business and sustainment lead DoD tech chief's priorities |first=Joe |last=Gould |date=12 October 2021 |website=Defense News}}</ref><ref name= nurkin >Tate Nurkin [https://breakingdefense.com/2022/02/to-catch-china-and-russia-in-hypersonic-race-us-must-embrace-risk-now/ (9 Feb 2022) To catch China and Russia in hypersonic race, US must embrace risk now]</ref> A hypersonic test bed aims to bring the frequency of tests to one per week.<ref name= machTb >Courtney Albon  [https://www.defensenews.com/pentagon/2022/11/08/pentagon-test-bed-to-ramp-up-development-of-hypersonics/ (8 Nov 2022) Pentagon test bed to ramp up development of hypersonics] MACH-TB</ref><ref name= trmc >Courtney Albon [https://www.defensenews.com/battlefield-tech/2023/01/06/pentagon-racing-to-restore-us-superiority-in-hypersonics/ (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.</ref>
;Other programs
{{wipe|France}},<ref name=CRS1/> {{wipe|Australia}},<ref name=CRS1/> {{wipe|India}},<ref name= indiaCrs2021>World Affairs [https://www.youtube.com/watch?v=xem882HXptc (22 Oct 2021) India Is One Of The Few Countries Working On Hypersonic Missiles : U.S. Congressional report] BrahMos 2</ref> {{wipe|Germany}},<ref name=CRS1/> {{wipe|Japan}},<ref name=CRS1/> {{wipe|South Korea}}<ref name="auto">{{Cite web|url=https://aviationweek.com/defense-space/missile-defense-weapons/south-korea-unveils-hypersonic-cruise-missile-prototype|title=South Korea Unveils Hypersonic Cruise Missile Prototype Concept &#124; Aviation Week Network|website=aviationweek.com}}</ref> and North Korea<ref name=":03">{{Cite news |last=Gale |first=Alastair |title=What Are Hypersonic Missiles and Who's Developing Them? |url=https://www.wsj.com/articles/hypersonic-missiles-11643688227 |access-date=2022-11-14 |newspaper=Wall Street Journal |date=February 2022 |language=en-US}}</ref> and [[Religion:Iran|Iran]]<ref>{{Cite news |date=2022-11-10 |title=Iran says it has built hypersonic ballistic missile -Tasnim |language=en |work=Reuters |url=https://www.reuters.com/world/middle-east/iran-says-it-has-built-hypersonic-ballistic-missile-tasnim-2022-11-10/ |access-date=2022-11-14}}</ref> also have hypersonic weapon research programs.<ref name=CRS1/>

{{anchor|Australia}}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.<ref>{{cite news |url=https://thediplomat.com/2020/12/australia-to-acquire-hypersonic-weapons-capability-in-collaboration-with-us/ |title=Australia to Acquire Hypersonic Weapons Capability in Collaboration with US |work=The Diplomat |first=Abhijnan |last=Rej |date=2 December 2020 |accessdate=4 March 2021}}</ref> Small and large companies will all contribute to the development of these hypersonic missiles,<ref>{{Cite web |url=https://www.afr.com/politics/federal/australia-to-help-develop-hypersonic-missiles-20201130-p56j75 |title=Australia to help develop hypersonic missiles |date=30 November 2020}}</ref> named SCIFIRE in 2022.<ref name= scifire>Colin Clark [https://breakingdefense.com/2022/01/aussies-unveil-new-hypersonics-center-signal-distance-from-ukraine-crisis/ (25 Jan 2022) Aussies unveil new hypersonics center, signal distance from Ukraine crisis]</ref><ref name=hacmScifire >Stephen Losey [https://www.defensenews.com/air/2022/09/22/raytheon-wins-985m-contract-to-develop-hypersonic-missiles/ (22 Sep 2022) Raytheon wins $985M contract to develop hypersonic missile] HACM possible fielding by FY2027</ref>

==Proposed==

; Aircraft:
[[File:Hermeus Halcyon depiction.png|thumb|Artist depiction of the ''Halcyon'' commercial hypersonic transport aircraft proposed by the [[Company:Hermeus|Hermeus corporation]] in flight.]]
*{{flagicon|China}} I-Plane<ref>Cui, et al. (February 2019) [http://www.aerospacengineering.net/?p=80856 Hypersonic I-shaped aerodynamic configurations] ''Science China Physics, Mechanics & Astronomy'' 61:024722 Wind tunnel proposal</ref>
*{{flagicon|Brazil}} [[Engineering:14-X|14-X]]
*{{flagicon|India}} [[Engineering:Avatar (spacecraft)|Avatar (spacecraft)]]<ref>{{cite web |url=http://www.spsmai.com/experts-speak/?id=111&q=ISROs-AVATAR-making-India-proud-again |title=ISRO's AVATAR – making India proud again |website=www.spsmai.com}}</ref>
*{{flagicon|India}} [[Engineering:Advanced Technology Vehicle|Advanced Technology Vehicle]]<ref>{{cite web |url=https://www.isro.gov.in/launchers/isro%E2%80%99s-scramjet-engine-technology-demonstrator-successfully-flight-tested |title=ISRO's Scramjet Engine Technology Demonstrator Successfully Flight Tested – ISRO |website=www.isro.gov.in}}</ref>
*{{flagicon|US}} [[Engineering:XS-1 (spacecraft)|DARPA XS-1]]<ref>{{cite web |url=https://www.space.com/boeing-withdraws-darpa-military-space-plane.html |title=DARPA scraps XS-1 military space plane project after Boeing drops out |first=Mike Wall 23 |last=January 2020 |website=Space.com |date=23 January 2020}}</ref>
*{{flagicon|Switzerland}} Destinus [[Engineering:Hydrogen-powered aircraft|hydrogen-powered]] hypersonic aircraft. A prototype was tested last year.<ref>{{cite web | url=https://www.9news.com.au/world/hypersonic-plane-race-could-see-australians-fly-to-europe-in-five-hours/713709de-66f1-4cb7-9835-a45f0e2493f8 | title=Sydney to Europe in four hours? New contender enters hypersonic plane race | date=5 May 2023 }}</ref><ref name=":0">{{Cite web |last=Blain |first=Loz |date=2022-02-09 |title="Russia's Elon Musk" is developing hypersonic rocket cargo planes |url=https://newatlas.com/aircraft/destinus-hypersonic-aircraft/|access-date=2022-02-10 |website=New Atlas |language=en-US}}</ref><ref>{{cite web | url=https://www.forbes.com/sites/erictegler/2023/02/28/swiss-hypersonic-startup-destinus-appears-destined-for-the-same-path-as-its-american-counterparts/ | title=Swiss Hypersonic Startup Destinus Appears Destined for Same Path as U.S. Counterparts | website={{wipe|Forbes}} }}</ref>
*{{flagicon|US}} [[Engineering:Dream Chaser|Dream Chaser]]<ref>{{cite web |url=https://www.sncorp.com/what-we-do/dream-chaser-space-vehicle/ |title=Dream Chaser® – America's Spaceplane™ &#124; Sierra Nevada Corporation |website=www.sncorp.com}}</ref>
*{{flagicon|US}} [[Engineering:NASA X-43|NASA X-43]]<ref>{{cite web |url=https://www.aerospace-technology.com/projects/x43/ |title=NASA X-43 |website=Aerospace Technology}}</ref><ref>{{cite web |url=http://www.nasa.gov/centers/armstrong/history/experimental_aircraft/X-43A.html |title=X-43A (Hyper-X) |first=Monroe |last=Conner |date=4 April 2016 |website=NASA}}</ref> 
*{{flagicon|US}} HyperSoar<ref>{{cite web |url=https://fas.org/man/dod-101/sys/ac/hypersoar.htm |title=HyperSoar – Military Aircraft |website=fas.org}}</ref>
*{{flagicon|Germany}} [[Engineering:HyperMach SonicStar|HyperStar]] hypersonic passenger airliner<ref>{{cite web |url=https://newatlas.com/hypermach-sonicstar-ssbj-concept/18974/ |title=HyperMach unveils SonicStar supersonic business jet concept |website=newatlas.com |date=21 June 2011}}</ref>
*{{flagicon|US}} Falcon HTV-2<ref>{{cite web |url=https://www.darpa.mil/program/falcon-htv-2 |title=Falcon HTV-2 |website=www.darpa.mil}}</ref>
*{{flagicon|US}} [[Company:Boeing Commercial Airplanes|Boeing Commercial Airplanes]] hypersonic airliner Concept<ref>{{cite news |title=Boeing Unveils Hypersonic Airliner Concept |date=26 June 2018 |work=Aviation Week |url-access=subscription |url=https://aviationweek.com/air-transport/boeing-unveils-hypersonic-airliner-concept}}</ref><ref>{{cite web |first=Joe |last=Pappalardo |date=26 June 2018 |title=How Boeing's Hypersonic Passenger Plane Concept Works |work=Popular Mechanics |url=https://www.popularmechanics.com/flight/a21948533/boeing-hypersonic-passenger-plane-concept/}}</ref>
*{{flagicon|US}} [[Engineering:Lockheed Martin SR-72|Lockheed Martin SR-72]]<ref>{{cite web |url=https://www.airforce-technology.com/projects/sr-72-hypersonic-demonstrator-aircraft/ |title=SR-72 Hypersonic Demonstrator Aircraft |website=Airforce Technology}}</ref>
*{{flagicon|Russia}} [[Astronomy:Kholod|Kholod]]
*{{flagicon|Russia}} [[Engineering:Ayaks|Ayaks]] waverider spaceplane
*[[File:ESA logo.png|24x24px]] [[Astronomy:Programme for Reusable In-orbit Demonstrator in Europe|Programme for Reusable In-orbit Demonstrator in Europe]] (PRIDE)
*{{flagicon|Germany}} [[Engineering:Saenger (spacecraft)#Saenger II|Sänger II]]<ref>{{cite web |url=http://www.astronautix.com/s/saengerii.html|archive-url=https://web.archive.org/web/20160801095741/http://www.astronautix.com/s/saengerii.html|url-status=dead|archive-date=1 August 2016 |title=Saenger II |website=www.astronautix.com}}</ref>
*{{flagicon|Australia}} [[Engineering:HyShot|HyShot]]
*{{flagicon|Germany}} Hytex<ref>{{cite web |url=http://www.astronautix.com/h/hytex.html|archive-url=https://web.archive.org/web/20161228022401/http://astronautix.com/h/hytex.html|url-status=dead|archive-date=28 December 2016 |title=Hytex |website=www.astronautix.com}}</ref>
*{{flagicon|Germany}} Horus<ref>{{cite web |url=http://www.astronautix.com/h/horus.html|archive-url=https://web.archive.org/web/20161227210756/http://astronautix.com/h/horus.html|url-status=dead|archive-date=27 December 2016 |title=Horus |website=www.astronautix.com}}</ref>
*{{flagicon|Germany}} [[Engineering:Sharp Edge Flight Experiment|SHEFEX]]
*{{flagicon|UK}} [[Engineering:Skylon (spacecraft)|Skylon]]<ref>{{cite web |url=https://www.space.com/19872-skylon-space-plane-human-spaceflight.html |title=Skylon Space Plane: The Spacecraft of Tomorrow |first=Markus Hammonds 20 |last=February 2013 |website=Space.com |date=20 February 2013}}</ref>
*{{flagicon|UK}} [[Engineering:Reaction Engines A2|Reaction Engines A2]]
*{{flagicon|UK}} Hypersonic Air Vehicle Experimental (HVX)<ref>{{cite web | url=https://www.rolls-royce.com/media/press-releases/2022/18-07-2022-delivering-the-future-of-uk-hypersonic-capabilities.aspx | title=Delivering the future of UK Hypersonic capabilities }}</ref><ref>{{cite web | url=https://aviationweek.com/shownews/farnborough-airshow/uk-unveils-hvx-hypersonic-demonstrator-plan | title=UK Unveils HVX Hypersonic Demonstrator Plan &#124; Aviation Week Network }}</ref> with Concept V aircraft<ref>{{cite web | url=https://www.janes.com/defence-news/news-detail/farnborough-2022-uk-reveals-concept-v-hypersonic-aircraft | title=Farnborough 2022: UK reveals 'Concept V' hypersonic aircraft }}</ref>
*{{flagicon|Australia}} Spartan<ref>{{cite journal |author1=D. Preller |author2=P. M. Smart |title=Abstract: SPARTAN: Scramjet Powered Accelerator for Reusable Technology AdvaNcement |journal=2014 ReinventingSpace Conference (Rispace 2014) |date=23 June 2021 |url=http://rispace.org/wp-content/uploads/2015/03/33_preller.pdf}}</ref>
*{{flagicon|EU}} HEXAFLY<ref>{{cite web |title=High-Speed Experimental Fly Vehicles – INTernational |publisher=European Space Agency |url=http://www.esa.int/Enabling_Support/Space_Engineering_Technology/High-Speed_Experimental_Fly_Vehicles_-_INTernational}}</ref>
*{{flagicon|Germany}} [[Engineering:SpaceLiner|SpaceLiner]]<ref>{{cite news |url=https://www.cnn.com/travel/article/spaceliner-mach-25/index.html |title=Space tech meets aviation: The hypersonic revolution |first=Miquel |last=Ros |website=CNN}}</ref>
*{{flagicon|EU}} STRATOFLY<ref>{{Cite web |url=https://www.nbcnews.com/mach/science/hypersonic-airliner-would-take-you-los-angeles-tokyo-under-two-ncna1045986 |title=This hypersonic airliner would take you from Los Angeles to Tokyo in under two hours |website=NBC News|date=23 August 2019 |access-date=9 October 2020}}</ref>
*{{flagicon|Japan}} [[Engineering:Zero Emission Hyper Sonic Transport|Zero Emission Hyper Sonic Transport]]
*{{flagicon|US}} [[Company:Hermeus|Hermeus]] Quarterhourse unmanned hypersonic demonstrator designed to land and take-off on conventional runways.<ref>{{cite web |url=https://www.aerospacetestinginternational.com/news/engine-testing/hermeus-reveals-quarterhorse-hypersonic-flying-testbed.html |title=Hermeus reveals Quarterhorse hypersonic flying testbed |date=November 15, 2021 |website=aerospacetestinginternational.com}}</ref>
*{{flagicon|US}} [[Company:Hermeus|Hermeus]] Halcyon hypersonic transport<ref>{{Cite web |url=https://www.hermeus.com/halcyon |title=HALCYON |website=Hermeus}}</ref>
*{{flagicon|US}} Venus Aerospace ''Stargazer'' hypersonic airliner<ref name=opCondition >Jeff Spry [https://www.space.com/venus-aerospace-hypersonic-plane-design/ (29 Jun 2022) Venus Aerospace unveils its dart-like Mach 9 plane design] meant to operate at 32 mile altitude at 7000 mph.</ref> with rotating detonation rocket engine<ref name= rotatingEngine >prnewswire [https://www.venusaero.com/venus-aerospace-benchmarks-new-hypersonic-engine/ (27 Oct 2022) Venus Aerospace Benchmarks New Hypersonic Engine]</ref><ref name=rotatingEngineVideo >Scott Manley [https://www.youtube.com/watch?v=rG_Eh0J_4_s (2021) What Is A Rotating Detonation Engine - And Why Are They Better Than Regular Engines]</ref>
*{{flagicon|Germany}} POLARIS Raumflugzeuge GmbH is developing and testing a hypersonic spaceplane for the German Armed Forces in Peenemünde<ref>https://aviationweek.com/defense-space/space/german-spaceplane-designer-flies-flight-control-demonstrator</ref><ref>https://aviationweek.com/aerospace/commercial-space/polaris-flies-german-funded-spaceplane-demonstrator</ref>

; Bombers:
*{{flagicon|US}} Expendable Hypersonic Air-Breathing Multi-Mission Demonstrator ("Mayhem")<ref name= mayhem >{{Cite web |url=https://www.airforcemag.com/mayhem-will-be-larger-multi-role-air-breathing-hypersonic-system-for-usaf/ |title='Mayhem' Will Be Larger, Multi-Role Air-Breathing Hypersonic System for USAF |date=19 August 2020|access-date=9 October 2020}}</ref> 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,<ref name= mayhemIsr >Joseph Trevithick  [https://www.thedrive.com/the-war-zone/mayhem-hypersonic-strike-recon-jet-contract-awarded-to-leidos (16 Dec 2022) Mayhem Hypersonic Strike-Recon Jet Contract Awarded To Leidos] "Mayhem air vehicle to demonstrate strike and intelligence-gathering capabilities"</ref> as a possible bomber.<ref name=mayhemStrike >Kris Osborn [https://warriormaven.com/air/hypersonic-attack-drone-mayhem-air-force-research-lab (10 Jan 2023) Air Force Research Lab Advances "First-of-its-Kind" Armed Hypersonic Attack Drone] "The new hypersonic vehicle, called Mayhem, will perform surveillance and 'strike' missions"</ref><ref name=draperPartnership /> [[Company:Leidos|Leidos]] is preparing a system requirements review, and a conceptual design for these missions.<ref name= leidosPlansPartners  >CHRISTOPHER PLAIN [https://thedebrief.org/the-u-s-air-force-is-preparing-to-unleash-hypersonic-mayhem/ (21 Dec 2022) THE U.S. AIR FORCE IS PREPARING TO UNLEASH HYPERSONIC MAYHEM] AFRL project; design package to be ready by 2027</ref> Draper Labs has begun a partnership with Leidos.<ref name=draperPartnership >Darren Orf [https://www.yahoo.com/news/project-mayhem-air-forces-secret-152400142.html (20 Jan 2023) Project Mayhem, the Air Force's Secret Hypersonic Bomber, Has Begun Cooking]</ref> 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, [[Company:Calspan|Calspan]], and Draper.<ref name= kratosMayhem >Christopher McFadden  [https://interestingengineering.com/innovation/kratos-project-mayhem-hypersonic-missile (20 Jan 2023) US' hypersonic missile 'Mayhem' gets a boost from Kratos]</ref> DIU is soliciting additional Hypersonic and High-Cadence Airborne Testing Capabilities (HyCAT), for Mayhem.<ref name= diuMayhem >Theresa Hitchens [https://breakingdefense.com/2023/01/diu-asks-industry-for-help-getting-hypersonic-test-jet-closer-to-lift-off/ (24 Jan 2023) DIU asks industry for help getting hypersonic test jet closer to lift off]</ref>

; Cruise missiles:
*{{flagicon|US}} Advanced Hypersonic Weapon (AHW)<ref>{{cite web |url=https://www.army-technology.com/projects/advanced-hypersonic-weapon-ahw/ |title=Advanced Hypersonic Weapon (AHW) |website=Army Technology}}</ref>
*{{anchor|HAWC}}{{flagicon|US}} 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 [[Astronomy:Scramjet|scramjet]]-powered hypersonic missile to successfully complete a free flight test in the 2020s.<ref name= hawcProgramOfRecordWillBeHacm >BreakingDefense [https://breakingdefense.com/2022/04/air-breathing-hypersonics-a-new-tactical-capability-to-counter-evolving-threats/ (18 Apr 2022) Air-breathing hypersonics: A new tactical capability to counter evolving threats] "For HAWC, that program of record will be the Air Force’s Hypersonic Attack Cruise Missile, or HACM"</ref><ref name= hawcTest2021 >[https://www.yahoo.com/news/u-successfully-flight-tests-raytheon-180251221.html Mike Stone (27 Sep 2021) U.S. successfully flight tests Raytheon hypersonic weapon - Pentagon]
*[https://breakingdefense.com/2021/09/darpa-hypersonic-cruise-missile-prototype-flies-at-last/ Theresa Hitchens (27 Sep 2021) DARPA Hypersonic Cruise Missile Prototype Flies At Last]</ref><ref name= hawc30Sep2021>Aviation Week [https://aviationweek.com/defense-space/missile-defense-weapons/raytheon-ends-air-launched-hypersonic-vehicle-test-drought (30 Sep 2021) Raytheon Ends Air-Launched Hypersonic Vehicle Test Drought]</ref><ref name="arrw">{{cite web |title=Air Force tests hypersonic weapon aboard B-52 for first time |url=https://www.upi.com/Defense-News/2019/06/14/Air-Force-tests-hypersonic-weapon-aboard-B-52-for-first-time/3411560517628/ |website=UPI}}</ref><ref name="R45811" /> 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".<ref name= hawcTest2021 /> HAWC is capable of sustained, powered maneuver in the atmosphere.<ref name= hawcVideo>World'sTech {{Cite web |url=https://www.youtube.com/watch?v=GAPjHjTraDY |title=USAF Completes 1st Free Flight Test of HAWC Hypersonic Weapon... |via=www.youtube.com}}</ref>{{rp| minute 0:55}} HAWC appears to depend on a rocket booster to accelerate to scramjet velocities operating in an oxygen-rich environment.<ref>Joseph Trevithick (18 June 2019), [https://www.thedrive.com/the-war-zone/28580/northrop-and-raytheon-have-been-secretly-working-on-scamjet-powered-hypersonic-missile "Northrop And Raytheon Have Been Secretly Working On Scramjet Powered Hypersonic Missile"], The Drive</ref><ref name="b1HypersonicWeapon">Kris Osborn (1 October 2019), [https://www.foxnews.com/tech/air-force-arms-b1-b-bomber-with-hypersonic-weapons "Air Force arms B1-B bomber with hypersonic weapons"], Fox News</ref> It is easier to put a seeker on a sub-sonic air-breathing vehicle.<ref name= plethora >{{cite web |url=https://breakingdefense.com/2020/03/hypersonic-missiles-plethora-of-boost-glide-cruise/ |title=Hypersonic Missiles: Plethora Of Boost-Glide & Cruise |first=Sydney J. Jr.|last=Freedberg  |date=3 March 2020}}</ref> In mid-March 2022 a HAWC Scramjet was successfully tested in an air-launched flight by a second vendor.<ref name= hawcMidMarch22 >Oren Liebermann [https://www.cnn.com/2022/04/04/politics/us-hypersonic-missile-test/index.html (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</ref><ref name= hollings >Alex Hollings [https://www.sandboxx.us/blog/us-successfully-tests-scramjet-powered-hypersonic-missile-in-secret/ (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"</ref> On 18 July 2022 Raytheon announced another successful test of its Hypersonic Air-breathing Weapon Concept (HAWC) scramjet, in free flight.<ref name= reutersStone >Mike Stone [https://kfgo.com/2022/07/18/u-s-successfully-flight-tests-raytheon-hypersonic-weapon-pentagon-2/ (18 Jul 2022) U.S. successfully flight-tests Raytheon hypersonic weapon -Pentagon]</ref><ref name=4aurTestsFy2024 >Audrey Decker [https://www.defenseone.com/policy/2023/03/air-force-wont-buy-hypersonic-missiles-2024/383987/ (14 Mar 2024) Air Force Won’t Buy Hypersonic Missiles in 2024, Official Says]</ref>
*#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".<ref name= moreHypersonics >Courtney Albon [https://www.defensenews.com/battlefield-tech/2022/05/09/darpa-maturing-scramjet-powered-hypersonic-weapon-concept-through-follow-on-program/ (9 May 2022) DARPA seeks funding for next phase of hypersonic weapon]</ref>
*{{anchor|HCSW}}{{flagicon|US}} Hypersonic Conventional Strike Weapon (HCSW - pronounced "hacksaw")<ref name="hcsw"/> passed its critical design review (CDR)<ref name= hcswIdiq >GlobalSecurity.org [https://www.globalsecurity.org/military/systems/munitions/hcsw.htm (10 Feb 2020) Hypersonic Conventional Strike Weapon (HCSW)]</ref> but this IDIQ (indefinite duration, indefinite quantity)<ref name= hcswIdiq /> contract was terminated in favor of ARRW because twice as many ARRWs will fit on a bomber.<ref name= hcswIsLargerThanArrw >John A. Tirpak [https://www.airforcemag.com/arrw-beat-hcsw-because-its-smaller-better-for-usaf/ (2 Mar 2020) Roper: The ARRW Hypersonic Missile Better Option for USAF]</ref> 
*{{flagicon|USSR}} [[Engineering:Kh-45|Kh-45]] (cancelled)
*{{flagicon|Russia}} Zircon<ref>[https://nationalinterest.org/blog/buzz/bad-news-russias-tsirkon-hypersonic-missiles-are-coming-2025-192495 Mark Episkopos (26 Aug 2021)  Bad News: Russia's Tsirkon Hypersonic Missiles Are Coming 2025] 3M22 missile (the Tsirkon hypersonic missile) fielded to ships and submarines</ref><ref>Reuters [https://news.trust.org/item/20211004064956-qrwkc (4 Oct 2021) Russia test fires submarine-launched hypersonic Tsirkon missile for first time] 3M22 Tsirkon launched from Severodvinsk submarine for the first time</ref>
*{{flagicon|India}} [[Engineering:Hypersonic Technology Demonstrator Vehicle|Hypersonic Technology Demonstrator Vehicle]]
*{{flagicon|India}}/{{flagicon|Russia}} Brahmos-II
*{{flagicon|South Korea}} Hycore<ref name="auto"/>

; Glide vehicles:
*{{flagicon|US}} AGM-183A air launched rapid response weapon (ARRW, pronounced "arrow")<ref name="arrw" /><ref name="defensenews">Chris Martin (17 December 2019) [https://www.defensenews.com/industry/techwatch/2019/12/17/lockheed-awards-815m-contract-for-hypersonic-missile-motor/ "Lockheed awards $81.5M contract for hypersonic missile motor"], Defense News, HCSW $81.5M, ARRW</ref><ref name="R45811" /><ref name="arrwReviewed">[https://breakingdefense.com/2020/02/lockheed-martin-air-force-press-ahead-on-air-launched-hypersonic-missile/ Theresa Hitchens (27 February 2020) Lockheed Martin, Air Force Press Ahead On Air-Launched Hypersonic Missile ] =HSW-ab;   ARRW funding is augmented;</ref> 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;<ref>{{Cite web |last=Xiao |first=Bing |date=10 August 2020 |title=Air Force's Hypersonic Weapon Hits 'Major Milestone' in New Test |url=https://www.military.com/daily-news/2020/08/10/air-forces-hypersonic-weapon-hits-major-milestone-new-test.html |access-date=9 October 2020 |website=Military.com}}</ref><ref name="videoArrw">Military TV [https://www.youtube.com/watch?v=hLlQd1C-gfM (14 Feb 2021) AGM 183A Arrow U.S Long-range Hypersonic Missile] ARRW</ref> however, ARRW's launch sequence was not completed, as of 15 Dec 2021.<ref name="3rdFailure" /><ref name="arrwl16Dec21">Miltech insights [https://www.youtube.com/watch?v=TpmLh7BLaTM (18 Dec 2021) Third Test of US Hypersonic Missile AGM-183A Arrow Fails]</ref><ref name="2ndFailure">STEFANO D'URSO  {{Cite web |date=4 August 2021 |title=First Flight Test Of Hypersonic AGM-183A ARRW (Air-launched Rapid Response Weapon) Fails, Again. |url=https://theaviationist.com/2021/08/04/arrw-test-fails-again/}}</ref> Hundreds of ARRWs or other Hypersonic weapons are being sought by the Air Force.<ref>{{Cite web |last=McLeary |first=Paul |date=24 April 2020 |title=Hypersonics: DoD Wants 'Hundreds of Weapons' ASAP |url=https://breakingdefense.com/2020/04/hypersonics-dod-wants-hundreds-of-weapons-asap/ |access-date=9 October 2020}}</ref> 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.<ref name="moreTestingFunded">Valerie Insinna [https://breakingdefense.com/2022/03/air-force-cant-buy-its-first-hypersonic-arrw-as-planned-following-budget-cut/ (9 Mar 2022) Air Force can’t buy its first hypersonic ARRW as planned, following budget cut]</ref> A production decision on ARRW has been delayed for a year to complete flight testing.<ref name="AfStillUnconvinced">Stephen Losey [https://www.defensenews.com/air/2022/07/17/air-force-still-weighing-future-of-key-hypersonic-program/ (17 Jul 2022) US Air Force weighing future of key hypersonic program after two successful tests]</ref><ref name="arrwDelay">Oren Liebermann  [https://www.cnn.com/2022/04/07/politics/air-force-hypersonic-missile-program-delay/index.html ( Air Force delays hypersonic missile program after flight test 'anomalies'] AGM-183A ARRW</ref> On 14 May 2022 an ARRW flight test was successfully completed, for the first time.<ref name="1stArrwFlight">Oren Liebermann [https://www.cnn.com/2022/05/16/politics/us-air-force-hypersonic-missile-test/index.html (16 May 2022) US Air Force tests troubled hypersonic missile]</ref><ref name= 1stAllUpRoundArrw >Valerie Insinna [https://breakingdefense.com/2022/12/air-force-successfully-tests-first-fully-operational-air-launched-hypersonic-missile/ (9 Dec 2022) Air Force successfully tests first fully-operational air-launched hypersonic missile] AGM-183A ARRW's 1st all-up round was successfully tested, completing its flight path and successfully detonating, after 3 consecutive test failures (Apr, Jul, and Dec 2021), and 2 successful tests of the booster in May and July 2022</ref> 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.<ref name= need3moreAursOfArrw >John A Tirpak [https://www.airandspaceforces.com/three-more-successful-all-up-arrw-tests-required-before-production-decision/ (14 Dec 2022) Three More Successful All-Up ARRW Tests Required Before Production Decision] Air Force: "Three more 'all-up' flight tests of the AGM-183 Air-launched Rapid Response Weapon (ARRW) must succeed".</ref> No production decision will be made in 2024.<ref name= 4aurTestsFy2024/> The USAF now intends to end the ARRW development program, as of 29 March 2023.<ref name=arrwIsOver >Bloomberg [https://www.bloomberg.com/news/articles/2023-03-29/us-air-force-plans-to-end-lockheed-hypersonic-weapon-program#xj4y7vzkg (29 Mar 2023) US Air Force Plans to End Lockheed Hypersonic Weapon Program]</ref><ref name=2ndAurPartial >Michael Marrow [https://breakingdefense.com/2023/03/air-force-mum-on-whether-latest-arrw-hypersonic-test-was-successful/ (24 Mar 2023)  Air Force mum on whether latest ARRW hypersonic test was successful]</ref><ref name=failedArrwTest /><ref name= arrw22Aug2023 >Michael Marrow [https://breakingdefense.com/2023/08/air-force-wont-say-whether-newest-arrw-test-succeeded-echoing-past-failure/ (22 Aug 2023) Air Force won't say whether newest ARRW test succeeded, echoing past failure] An end-to-end test of a Middle Tier Acquisition (MTA) from Lockheed</ref><ref name= arrw21Aug2023 >Stephen Losey [https://www.c4isrnet.com/battlefield-tech/space/2023/08/21/us-air-force-fires-arrw-hypersonic-in-first-test-since-march-failure/ (21 Aug 2023) US Air Force fires hypersonic ARRW in first test since March failure] End-to-end test</ref>
*{{flagicon|US}} DARPA Tactical Boost Glide vehicle<ref>Dan Goure (20 June 2019) [https://nationalinterest.org/blog/buzz/hypersonic-weapons-are-almost-here-and-they-will-change-war-forever-63432 "Hypersonic Weapons Are Almost Here (And They Will Change War Forever)"] Lockheed-Martin vs Raytheon-Northrup</ref><ref>Steve Trimble (29 July 2019), [https://aviationweek.com/awindefense/raytheon-tactical-boost-glide-baseline-review-completed "Raytheon Tactical Boost Glide Baseline Review Completed"], ''Aviation Week''
*Robin Hughes (5 August 2019) [https://www.janes.com/article/90278/raytheon-darpa-complete-tbg-baseline-design-review "Raytheon, DARPA complete TBG baseline design review"], Jane's</ref><ref>Dr. Peter Erbland, Lt. Col. Joshua Stults () [https://www.darpa.mil/program/tactical-boost-glide "Tactical Boost Glide"]</ref>
*{{Flagicon|India}} [[Engineering:HGV-202F|HGV-202F]]

== Flown ==

; Aircraft:
*{{flagicon|US}} [[Engineering:North American X-15|North American X-15]] (crewed)<ref>{{cite web |url=http://www.nasa.gov/centers/armstrong/news/FactSheets/FS-052-DFRC.html |title=NASA Dryden Fact Sheets – X-15 Hypersonic Research Program |first=Yvonne |last=Gibbs |date=13 August 2015 |website=NASA}}</ref>
*{{flagicon|US}} Lockheed X-17<ref>{{cite web |url=http://www.designation-systems.net/dusrm/app1/x-17.html |title=Lockheed X-17 |website=www.designation-systems.net}}</ref>
*{{flagicon|US}} [[Engineering:NASA X-43|NASA X-43]]
*{{flagicon|US}} Boeing X-51<ref>{{cite web |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104467/x-51a-waverider/ |title=X-51A Waverider |website=U.S. Air Force}}</ref>
*{{flagicon|PRC}} WZ-8<ref>{{cite web |url=https://militarywatchmagazine.com/article/china-worlds-only-hypersonic-aircraft#:~:text=Multiple%20sources%20have%20indicated%20that,to%20pose%20a%20serious%20threat. |title=China Fields the World's Only Hypersonic Military Aircraft: What is the WZ-8 Capable Of? |website=Military Watch Magazine |date=5 December 2021}}</ref>
*{{flagicon|India}} HSTDV<ref>{{Cite news |date=12 June 2019 |title=DRDO conducts maiden test of hypersonic technology demonstrator |url=https://www.thehindu.com/news/national/drdo-conducts-maiden-test-of-hypersonic-technology-demonstrator/article27890922.ece |journal=The Hindu |last1=Peri |first1=Dinakar}}</ref>

; Glide vehicles:
* {{flagicon|RU}} [[Engineering:Avangard (hypersonic glide vehicle)|Avangard]]<ref>{{Cite web |title=Avangard (Hypersonic Glide Vehicle) – Missile Defense Advocacy Alliance |url=https://missiledefenseadvocacy.org/missile-threat-and-proliferation/todays-missile-threat/russia/avangard-hypersonic-glide-vehicle/ |access-date=9 October 2020}}</ref>
* {{flagicon|China}} [[Engineering:DF-ZF|DF-ZF]]
* {{flagicon|North Korea}} [[Engineering:Hwasong-8|Hwasong-8]]<ref name=":03" />
* {{flagicon|Iran}} Unnamed<ref name=":03" /><ref>{{Cite web |title=موشک هایپرسونیک سپاه رونمایی می‌شود- اخبار نظامی {{!}} دفاعی {{!}} امنیتی - اخبار سیاسی تسنیم {{!}} Tasnim |url=https://www.tasnimnews.com/fa/news/1401/08/20/2802408/%D9%85%D9%88%D8%B4%DA%A9-%D9%87%D8%A7%DB%8C%D9%BE%D8%B1%D8%B3%D9%88%D9%86%DB%8C%DA%A9-%D8%B3%D9%BE%D8%A7%D9%87-%D8%B1%D9%88%D9%86%D9%85%D8%A7%DB%8C%DB%8C-%D9%85%DB%8C-%D8%B4%D9%88%D8%AF |access-date=2022-11-14 |website=خبرگزاری تسنیم {{!}} Tasnim |language=fa}}</ref>

; Spaceplanes:
*{{flagicon|US}} [[Engineering:Space Shuttle orbiter|Space Shuttle orbiter]] (crewed)
*{{flagicon|USSR}} ''[[Engineering:Buran (spacecraft)|Buran]]'' (human-rated, only flew without crew)<ref>{{cite web |url=https://www.space.com/29159-buran-soviet-shuttle.html |title=Buran: The Soviet Space Shuttle |first=Elizabeth Howell 21 |last=April 2015 |website=Space.com |date=21 April 2015}}</ref>
*{{flagicon|India}} [[Astronomy:RLV-TD|RLV-TD]]<ref>{{cite web |url=https://www.isro.gov.in/launcher/rlv-td |title=RLV-TD – ISRO |website=www.isro.gov.in |access-date=17 March 2020 |archive-date=17 April 2021 |archive-url=https://web.archive.org/web/20210417233754/https://www.isro.gov.in/launcher/rlv-td |url-status=dead }}</ref>
*{{flagicon|US}} [[Astronomy:Boeing X-37|Boeing X-37]]<ref>{{cite web |author=Ba (Nyse) |url=https://www.boeing.com/defense/autonomous-systems/x37b/index.page |title=Autonomous Systems – X-37B |publisher=Boeing |date=1 January 2020 |access-date=18 March 2020}}</ref>
*{{flagicon|China}} [[Engineering:Shenlong (spacecraft)|Shenlong]]<ref>{{cite web |url=https://www.globalsecurity.org/space/world/china/shenlong.htm |title=Project 863-706 Shenlong ("Divine Dragon") |website=www.globalsecurity.org}}</ref>
*[[File:ESA logo simple.svg|20px|link=European Space Agency]] IXV<ref>{{Cite web |url=https://spaceflight101.com/spacecraft/ixv-intermediate-experimental-vehicle/ |title=IXV – Intermediate Experimental Vehicle – Spacecraft & Satellites|access-date=9 October 2020}}</ref>
*{{flagicon|USSR}} [[Engineering:BOR-4|BOR-4]]<ref>{{cite web |url=https://space.skyrocket.de/doc_sdat/bor-4.htm |title=BOR-4 |website=space.skyrocket.de}}</ref>
*{{flagicon|US}} [[Engineering:Martin X-23 PRIME|Martin X-23 PRIME]]<ref>{{cite web |url=https://www.456fis.org/MARTIN_MARIETTA_X-23A_prime.htm |title=The Martin Marietta X-23 Prime |website=www.456fis.org}}</ref>
*{{flagicon|US}} [[Engineering:ASSET (spacecraft)|ASSET]]<ref>{{cite web |url=http://www.astronautix.com/a/asset.html|archive-url=https://web.archive.org/web/20161227193424/http://astronautix.com/a/asset.html|url-status=dead|archive-date=27 December 2016 |title=Asset |website=www.astronautix.com}}</ref>
*{{flagicon|Japan}} [[Engineering:HYFLEX|HYFLEX]]<ref>{{cite web |url=https://global.jaxa.jp/projects/rockets/hyflex/ |title=JAXA &#124; Hypersonic Flight Experiment "HYFLEX" |website=JAXA &#124; Japan Aerospace Exploration Agency}}</ref>
*{{flagicon|China}} Chongfu Shiyong Shiyan Hangtian Qi (disputed)
*{{flagicon|China}} Jiageng-1<ref>{{cite web |url=https://steemit.com/space/@anzha/meet-the-jiageng-1-china-s-demonstrator-for-its-equivalent-of-the-darpa-xs-1 |title=Meet the Jiageng-1: China's Demonstrator for its Equivalent of the DARPA XS-1 |date=29 April 2019}}</ref>

==Cancelled ==

; Aircraft:
*{{flagicon|Nazi Germany}} [[Engineering:Silbervogel|Silbervogel]] (Sänger bomber)<ref>{{cite web |url=https://falsesteps.wordpress.com/2012/07/10/sanger-bredt-silbervogel/ |title=Sänger-Bredt Silbervogel: The Nazi Space Plane |first=Paul |last=Drye |date=10 July 2012}}</ref>
*{{flagicon|USSR}} [[Engineering:Keldysh bomber|Keldysh bomber]]<ref>{{cite web |url=http://www.astronautix.com/k/keldyshbomber.html|archive-url=https://web.archive.org/web/20160906180112/http://www.astronautix.com/k/keldyshbomber.html|url-status=dead|archive-date=6 September 2016 |title=Keldysh Bomber |website=www.astronautix.com}}</ref>
*{{flagicon|USSR}} [[Engineering:Tupolev Tu-360|Tupolev Tu-360]], follow-on to Tu-160
*{{flagicon|USSR}} [[Engineering:Tupolev Tu-2000|Tupolev Tu-2000]]<ref>{{cite web |url=http://www.astronautix.com/t/tu-2000.html|archive-url=https://web.archive.org/web/20161228024015/http://astronautix.com/t/tu-2000.html|url-status=dead|archive-date=28 December 2016 |title=Tu-2000 |website=www.astronautix.com}}</ref>
*{{flagicon|US}} [[Engineering:Lockheed L-301|Lockheed L-301]]

; Spaceplanes:
*{{flagicon|US}} [[Engineering:Boeing X-20 Dyna-Soar|Boeing X-20 Dyna-Soar]]
*{{flagicon|US}} [[Engineering:Rockwell X-30|Rockwell X-30]] (National Aerospace Plane)
*{{flagicon|US}} [[Engineering:Orbital Sciences X-34|Orbital Sciences X-34]]
*{{flagicon|USSR}} [[Engineering:Mikoyan-Gurevich MiG-105|Mikoyan-Gurevich MiG-105]]
*{{flagicon|US}} Tsien Spaceplane 1949<ref>{{cite web |first=Mark |last=Wade |title=Tsien Spaceplane 1949 |website=astronautix.com |url=http://www.astronautix.com/t/tsienspaceplane1949.html|archive-url=https://web.archive.org/web/20160915090422/http://www.astronautix.com/t/tsienspaceplane1949.html|url-status=dead|archive-date=15 September 2016}}</ref>
*{{flagicon|Japan}} [[Engineering:HOPE-X|HOPE-X]]<ref>{{cite web |url=http://www.astronautix.com/h/hope.html|archive-url=https://web.archive.org/web/20161221095301/http://www.astronautix.com/h/hope.html|url-status=dead|archive-date=21 December 2016 |title=HOPE |website=www.astronautix.com}}</ref>
*{{flagicon|US}} [[Astronomy:XCOR Lynx|XCOR Lynx]]
*{{flagicon|US}} [[Engineering:Lockheed Martin X-33|Lockheed Martin X-33]]<ref>{{cite web |url=http://www.nasa.gov/centers/armstrong/history/experimental_aircraft/X-33.html |title=Lockheed Martin X-33 |first=Monroe |last=Conner |date=30 March 2016 |website=NASA}}</ref>
*{{flagicon|France}} [[Engineering:Hermes (spacecraft)|Hermes]]<ref>{{cite web |url=http://www.astronautix.com/h/hermes.html|archive-url=https://web.archive.org/web/20160820192213/http://www.astronautix.com/h/hermes.html|url-status=dead|archive-date=20 August 2016 |title=Hermes |website=www.astronautix.com}}</ref>
*{{flagicon|US}} [[Engineering:Prometheus (spacecraft)|Prometheus]]<ref>{{cite web |url=https://www.popsci.com/technology/article/2010-12/jumping-new-space-race-orbital-sciences-unveils-mini-shuttle-spaceplane-design/ |title=Jumping into the New Space Race, Orbital Sciences Unveils Mini-Shuttle Spaceplane Design |website=Popular Science |date=16 December 2010}}</ref>
*{{flagicon|US}} [[Engineering:HL-20 Personnel Launch System|HL-20 Personnel Launch System]]
*{{flagicon|US}} [[Engineering:HL-42 (spacecraft)|HL-42]]
*{{flagicon|UK}} [[Engineering:BAC Mustard|BAC Mustard]]<ref>{{cite web |url=http://www.astronautix.com/m/mustard.html|archive-url=https://web.archive.org/web/20161228092312/http://astronautix.com/m/mustard.html|url-status=dead|archive-date=28 December 2016 |title=Mustard |website=www.astronautix.com}}</ref>
*{{flagicon|Russia}} [[Engineering:Kliper|Kliper]]<ref>{{cite web |url=http://www.astronautix.com/k/kliper.html|archive-url=https://web.archive.org/web/20160820192457/http://www.astronautix.com/k/kliper.html|url-status=dead|archive-date=20 August 2016 |title=Kliper |website=www.astronautix.com}}</ref>
*{{flagicon|UK}} [[Engineering:HOTOL|HOTOL]]
*{{flagicon|Weimar Republic}} Valier Raketenschiff<ref>{{cite web |title=Valier "Raketenschiff" (1929): Classic Rocketship Series #6 |work=The Virtual Museum of Flying Wonders |publisher=Fantastic Plastic Models |url=http://fantastic-plastic.com/valier-raketenschiff-by-fantastic-plastic-models.html}}</ref>
*{{flagicon|US}} Rockwell C-1057<ref>{{cite web |title=Rockwell C-1057 "Breadbox" Space Shuttle (1972) |work=The Virtual Museum of Flying Wonders |publisher=Fantastic Plastic Models |url=https://fantastic-plastic.com/rockwell-c-1057-breadbox-space-shuttle-by-fantastic-plastic.html}}</ref>

==See also==
*[[Physics:Hypersonic effect|Hypersonic effect]]
*[[Engineering:Supersonic transport|Supersonic transport]]
*[[Engineering:Lifting body|Lifting body]]
*[[Engineering:List of X-planes|List of X-planes]]
*[[Engineering:Thunderbird 1|Thunderbird 1]]

==Notes==
{{notelist}}

==References==
{{reflist}}

==Further reading==
*David Wright and Cameron Tracy, "Over-hyped: Physics dictates that [[Engineering:Hypersonic weapon|hypersonic weapon]]s cannot live up to the grand promises made on their behalf", ''Scientific American'', vol. 325, no. 2 (August 2021), pp.&nbsp;64–71. Quote from p.&nbsp;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==
{{Library resources box}}

*[http://naca.central.cranfield.ac.uk/reports/1958/naca-report-1382.pdf A comparative analysis of the performance of long-range hypervelocity vehicles]
*[https://www.japcc.org/keywords/hypersonic-vehicles/ (2022) Joint Air Power Competence Centre] (JAPCC)

[[Category:Aerodynamics]]
[[Category:Aerospace engineering]]
[[Category:Airspeed]]

{{Sourceattribution|Hypersonic flight}}