Hypersonic Weapons

A hypersonic weapon is a guided munition intended to precisely hit a specific target, with extreme force, from any point on the planet in a matter of minutes. Typically a hypersonic weapon is characterized by delivering the bulk of its destructive force via kinetic energy and relying on air-breathing or minimal on-board propellant to guide it to a target.

## Types

While rocket powered missiles technically move at hypersonic speeds, they are typically considered in a separate category of weapon. Recognizing the difficulty of striking mobile forces in the wars in Iraq and Afghanistan, the Americans were first to develop air-breathing hypersonic munitions, rocket assisted scramjets.

### **Aircraft**

Hypersonic aircraft were an early product of the first Russo-American Cold War with human operated experimental aircraft or "X-Planes" being developed in the U.S. The rocket-powered X-15 became the first fixed-wing aircraft to achieve hypersonic flight in 1961, however as the Space Race became a greater priority, research in hypersonic aircraft fell off. Hypersonic aircraft once again came to the forefrunt of aviation at the turn of the 21st Century with the flight of the X-43 in 2004, the first scramjet (supersonic combusting ramjet) to achieve hypersonic flight, topping out at Mach 9.6. The flight of the X-43 set the stage for a new generation of hypersonic X-planes like the X-51, the Russian BrahMos-II, and the DARPA Falcon program.

The development of hypersonic aircraft occured during the rise of unmanned aircraft, commonly known as drones. The very first drones dated back to the Cold War, and were used purely for reconnaissance or as targets for anti-aircraft weapons. These were normally unable to land by themselves, and had to be recovered in midair by modified airplanes or helicopters using a complicated "skyhook" device. It was not until the debut of the RQ-1 Predator in the 1990s that a drone was created that could operate with the versatility of a manned airplane. It was followed in rapid succession by a series of improved versions, as well as the first drone helicopters and jet fighters. Due to the extreme physical stresses experienced during hypersonic flight, every hypersonic aircraft developed during this period was also a drone, however, subsonic drone aircraft vastly outnumbered hypersonic or even supersonic aircraft until the 2030s.

Hypersonic drones would become the norm in areal warfare during the hypersonic Arms Race of the 2030s and 40s, with the US and Japan (and to a lesser extent, Turkey) developing successively faster and more agile hypersonic aircraft. Before the outbreak of WWIII, the Mitsubishi B-31 held the record for a cruising speed of Mach 10.9. Aircraft would eventually nearly double that record after the war broke out, with the American Northrop Grumman F/A-39 Jaguar achieving the record for fastest production aircraft of the war at a cruising speed of Mach 19.

### **Missiles**

The first cruise missiles entered service during the second world war, in the form of the V-1 "flying bomb" used by Germany. Powered by a crude pulse-jet engine, it was slow and unreliable, but was rapidly improved upon during the Cold War. During the early 21st Century, the most common cruise missile in service in the US Air Force was the BGM-109 Tomahawk. The Tomahawk was powered by a jet engine and used an onboard computer to navigate towards targets. However, it could not adjust its own course in flight and had to be pre-programmed before launch. Later cruise missiles were completely autonomous and could reach hypersonic speeds, usually being powered by ramjet engines. The first such missile to enter operational service was the Raytheon AGM-25 Scorpion, which entered service in 2027. These weapons and others played a major role in the Third World War.

### **Orbital Kinetic Weapons**

The concept for orbital kinetic weapons dates back to the 1950's  and Project Thor, which was an idea for a weapons system that launches telephone pole-sized kinetic projectiles made from tungsten from Earth's orbit to damage targets on the ground.  The concept was a mainstay of science fiction throughout the late twentieth century but never seriously considered by any major space power. The system however was revisited by the United States as a part of the Prompt Global Strike (PGS) Initiative. Orbit kinetic weapons were one of the alternatives to the proposed intercontinental ballistic missile or hypersonic cruise missile.

A 2003 air force study proposed a weapon that was basically "an orbiting tungsten telephone pole with small fins and a computer in the back for guidance". The proposed system would deorbit a 6.1 m × 0.3 m tungsten cylinder impacting at Mach 10, which would have a kinetic energy equivalent to approximately 11.5 tons of TNT (or 7.2 tons of dynamite). Despite popular misconceptions the rod could not merely be dropped, but had to be launched. In order for a rod to fall straight toward the center of Earth it would need to be launched away from the station with a tangential velocity equal in magnitude and opposite in direction from the orbiting station. This velocity would be in the range of approximately 7–8 km/s for satellites in low earth orbit.

The benefits of such a systems would be its reliability and responsiveness. It would be  satellite controlled, and have global strike capability. The weapon would be very hard to defend against. It has a very high closing velocity and small radar cross-section. Launch is difficult to detect. The time between deorbit and impact would only be a few minutes, and depending on the orbits and positions in the orbits, the system would have a worldwide range. There would be no need to deploy missiles, aircraft or other vehicles. Although the SALT II (1979) prohibited the deployment of orbital weapons of mass destruction, it did not prohibit the deployment of conventional weapons. The system is not prohibited by either the Outer Space Treaty or the Anti-Ballistic Missile Treaty. However many experts feared it’s deployment would likely initiate a new space arms race. Further the mass of such a cylinder is itself greater than 9 tons, would yield a relatively small explosion to its size and weight. With the high cost of placing materials in orbit and its likely inflammatory effect on the international system, the practical applications of such a system were deemed limited.

With expansion of the commercial space industries in the late 2010's, the cost of placing payloads into orbit dropped dramatically. Leading Air Force leadership to again study the feasibility of space based kinetic weapons. Before leaving office in 2020 President Trump authorized the first orbital kinetic weapons test. Conducted on July 18, 2020 on the Johnston Atoll. A 20 foot tungsten cylinder was fired from orbit, penetrating a bunker protected by 50 feet of hardened concrete and detonating with the force of 11 tons of dynamite.

Though the test wen was  successful as it went completely and met its tactical goals, growing tension with the Russian Federation and China prevented its deployment. Subsequent administrations authorized further studies but failed to order further testing in light of arms control agreements between the U.S. and Eurasian powers over the placing of offensive space to earth weapons in orbit (see SALT III and SALT IV agreements) . Space warfare lobbyists  inside the U.S. defense establishment continued to press for similar systems, throughout the 2020s and 2030s. The U.S. conducted theoretical tests at the Livermore National Laboratories throughout this period.

After the Thanksgiving Day attacks the U.S. declared all space and strategic weapons limitations null and void. In a nod to the original study the U.S. deployed dozens of Milnjor Class Kinetic Weapons satellites as a part of Project Avenger. The Milnjor class Mark 1 Orbital Kinetic Weapons platform or (OKW) carried twenty four Tungsten Darts, of variety of sizes and density based on their mission requirements. Once fired these darts produced a range of explosive yields from 11 tons to 1.5 kilotons upon impact. Milnjor Platforms darts took part of the strategic bombing of both Turkey and Japan. The impunity with which the U.S. dropped these weapons over Coalition nations had a devastating psychological effect and was instrumental in the their surrender.

In the wake of the devastating Coalition hypersonic missile strikes on the East and West coasts, post war re-arming assessments advised shifting most of the countries strategic weapons into orbit.  OKW's became a key part of the post war space militarization. Over the next fifty years hundreds of weapons platforms were placed in low and medium earth orbits. Learning from the destruction of the basestars at the outbreak of the war, second generation platforms were provided with limited abilities to maneuver away from threats in orbit and on the ground. By the 2080s third generation platforms the ability to shift from low to medium earth orbit to avoid attacks from ground based anti-sat missiles. Because of the U.S. preponderance in space, platforms were not provided with the ability to return fire on other targets in orbit.

Kinetic strikes were used extensively in the First Nations War and Second Mexican-American War. By the end of the Second Mexican War their use had become so ubiquitous that they were no longer considered only strategic weapons, but used on the tactical level. By the late 2090’s, OKW’s were  increasingly at the disposal of battalion and even company commanders. Guardiola Terrorists avoided attacking U.S. orbital Kinetic Weapons platforms manned by space command out of fear of start a direct conflict with the United States Space Command, however this period caused great consternation to Space Force as the platforms were now considered too vulnerable. OKW strikes were used extensively during the siege of the Guardiola compound.

THe vulnerabilities displayed in the Guardiola incident led  to the development of the fourth generation of OKW platforms, the most famous being the Mark XXI. The Mark XXI was the first OKW  truly designed for self defense. Equipped with greater maneuverability, point defense systems, holographic projectors to obscure it from ground telescopes and other forms of stealth to hide its heat and electronic signature. The Mark XXI  was significantly more self sufficient and re-usable than its predecessors. While the Mark I or Milnjor class, was nothing more than a projectile launcher, later platforms were equipped with ability to alter the density and size of their projectiles depending upon their missions. The Mark XXI was outfitted with the latest automated industrial fabricators, which allowed it manufacture projectiles of not only varying size and density, but material as well. Incorporating new super dense materials alloys and materials, increasing their effectiveness.  This required the platform to be resupplied only with raw materials and not individual ordinance, greatly decreasing its logistic footprint .

With the emergence of the Mexican Vacuum Command in near Earth Space in 2113, the value of OKW Platforms were again questioned.  As Mexico began flooding Near Earth space with autonomous offensive drones, Space Force command focused its construction on more capital ships and fighters and bombers. Intern Mexico eschewed  large scale construction of OKW platforms for mobile drones and capital ships. However by 2028 Mexico deployed several versions of its own OKW platforms, none were as sophisticated as the Mark XXI. Still the U.S maintained over 150 fourth generation weapons platforms dating from the Guardiola incident.

Orbital Weapons Platforms played little role in the opening phases of the Third Mexican American War. At the outset of the Second Civil War, President Halvidar banned orbital strikes on U.S. soil. However the after the Mexican Intervention and liberal use of nuclear weapons. President Halvidar lifted the self imposed ban on on November 25, 2135. Striking Mexican held assets in the South West. However analysts fears of there vulnerability were quickly proven correct, as orbital bombardments by Mexico and the US were constantly being interrupted by space forces on both sides, leaving the fighting on Earth largely to terrestrial forces. A flaw in Mark XXI’s camouflage allowed Mexican space assets to detect its location after firing. With a high rate of attrition and Space Command not devoting any resources on their replacement, only eighteen OKW platforms were still intact at the beginning of operation starlight. By 2137 OKW were increasingly relegated from strategic bombardment to ground support and other tactical missions as OKWs were being replaced by Relativistic Space Guns, which could only be fired from Cruiser or dreadnought class vessel. Twelve OKW's survived the war and with the outbreak of American enforced disarmament no new platforms were constructed. The twelve remaining platforms were deployed in orbit over the few states residing outside the American system in Central Asia.

### **Railguns**

*For more information, see Railgun*

TBA

### **Microartillery**

Pioneered during the World War III, microartillery refers to any number of guided hypersonic munitions small enough to be deployed from multiple modules on an armored solider, and while sub-sonic varieties are quite common, hypersonic munitions of this scale began to enter service by the Second Mexican-American War. The most common hypersonic microartillery munition is the HIM-14 Diamondback II, a 30mm warhead typically clustered in a 6 chamber hip shoulder mounted missile tube, although it is more common on drones which can have dozens of firing tubes. The projectile, like most hypersonic microartilelry, is propelled by a light railgun in the launch tube which along with getting it up to supersonic speeds pulls in enough supersonic air for the onboard ramjet to take it to hypersonic velocities. Like all forms of artillery, hypersonic munitions must first ascend along parabolic arc before being guided to its target, however this arc tends to be far larger (on the order of kilometers) for hypersonic munitions.