Continuing on with hypersonics: Rail guns are one of several technologies that look likely to debut on near future battlefields. Magnetic acccelerators firing projectiles at speeds greater than five times that of sound, along with hypersonic missiles, hold transformative possibilities. Among these is the potential to blur the line between air-defense and ground-to-ground direct fire weapons for land warfare platforms.
A vehicle carrying the railgun equivalent of a 25mm chaingun could not only hit other ground platforms at ranges and with striking power well in excess of current rounds, but also engage air targets at ranges and altitudes well beyond those of present day air-defense guns, if equipped with a suitable fire control system. The same is true of vehicles carrying hypersonic missiles. An unguided line of sight air-breathing or rocket-powered hypersonic missile would outrace any current main gun tank round or air-defense artillery cannon shot. It could be both targeted at an aircraft or fired at armored vehicles like a tank cannon.
With main gun and chain gun shoot downs of Iraqi helicopters reported by US Abrams tanks and Bradly fighting vehicle crews going back to the 1991 Gulf War, this isn't something entirely new. Still, in the near future even fast movers at high altitudes might find themselves under fire from rail guns and hypersonic anti-tank missiles on just about every armor platform. Additionally, if the missiles have some guidance and maneuvering capability, a ground vehicle with multiple launch capability could theoretically target and simultaneously fire on several ground and air vehicles at the same time.
Why would guidance be in doubt? Maneuvering at hypersonic is difficult in the sense of it being tricky to not shred the vehicle. Turning at those speeds involves tremendous forces. Imagine air as the fluid medium equivalent of liquid concrete. Especially for weapons traveling at around Mach 10.
It's likely that tactical hypersonic missiles might preform leading course corrections to compensate for a target's movement during the early seconds or fraction of a second of acceleration, then fly straight on an interception course. If that seems like an unlikely arraignment because of lag time, remember that we're looking at missiles that will fly faster, possibly even twice as fast as current bullets or even main gun tank rounds.
Currently there are hypersonic missiles that can put explosive warheads anywhere in the world within thirty minutes. Their use would be devastating in the opening hour of a war, destroying military airfields, naval ports, and command and control centers, as well as actively tracked warships. Additionally, since these are missiles with near orbital speeds and steep warhead descent paths, they'd be difficult to successfully engage for almost all current air-defense systems.
In present day conflict most combatants would find them all but unstoppable.
The main drawback to the use of these missiles is that they're all ICBMs. Even if their nuclear payloads were swapped out for conventional warheads, any nation with a missile tacking capability would not be able to tell if the ballistic packages arcing were nuclear or not. Faced with the possibility of mass casualties, national annihilation, or being rendered helpless on the global stage, they might not be willing to wait for confirmation before launching a nuclear response.
Complicating the use of ICBMs as conventional global strike delivery vehicles, the shortest flight paths are generally over the poles for any conflict involving the United States. Which means passing over Russia -- a country that could be touchy to say the least if it spotted a system built for nuclear warfare in use. In a purely Eurasian conflict the arcs of ICBM or long distance ballistic missile flight paths traveling from their launch point to target would almost certainly pass over countries who might respond in kind, unable to be entirely certain who the ultimate intended recipient is.
Some of the current set of hypersonic strike vehicles under development by China, India, and the United States are more akin to cruise missiles than traditional ballistic missiles. Vehicles with a near global, or at least transoceanic reach that hit targets nearly on the far side of the world less than an hour after launch, with the ability to make multiple course corrections while underway.
Hypersonic is the New Stealth
The above is a tagline or summation I've come across in several articles and discussions about hypersonic weaponry. That in the near future hypersonic will have the kind of transformative impact, that stealth aircraft have had one modern war. Which is actually kind of a crap comparison. Why? Because stealth in combat has largely been limited to a handful of US platforms used against Iraq and Serbia during the 1990s. And almost entirely against a small set of high-value targets. For the most part the evolution of aerial warfare has been dominated by improved targeting and bomb guidance systems at a time when optically and radar-guided air-defense cannon systems and a proliferation of handheld systems pushed ground attack craft up above 10,000 feet (3048 meters).
On the other hand there is something instructive about the comparison taken at another level. The sheer speed of hypersonic weaponry may render them difficult to acquire for engage. The American SR-71 reconnaissance aircraft possessed a combination of speed, low radar cross section, and operational altitude that made it untouchable, even after the Soviet Union began fielding systems designed to shoot it down.
Hyerpsonic global strike vehicles as currently conceived would be well beyond the ability of current air-defense systems to engage, let alone alone destroy. Traveling faster than than any current direct fire cannon round, they'd offer only a the narrowest of interception windows -- assuming the ground or air stations detect the missiles far enough out to successfully acquire and fire on.
Hypersonic as Peer Technology and Destabilizing Force
In another fifteen or twenty years hypersonic may be the dominant force in strike technology, with unmanned missiles and mach 5+ delivery drones filling the niche currently occupied by bombers. carrier-based aircraft, and medium to short-ranged ballistic missiles. Mounting an effective defense will require a panoply of hypersonic air-defense systems along with a new generation of sensor systems capable of finding and targeting those weapons. Nations without the tech will essentially be as vulnerable to devastating air strikes as most countries presently are to the US Air Force and Navy.
Or perhaps more so. At present use of the United States' combined air fleets against an opponent demands a large and impossible-to-hide mobilization. Even deploying a squadron-sized element to strike ISIL targets in Syria or movement to reinforce South Korea against threats from its belligerent brother to the north have proven impossible to conceal in a world of crowded air travel corridors and urban skies. On the other hand, hypersonic strike weapons could appear over the horizon with little to no notice thirty minutes after launch from another hemisphere, and moving so quick as to demand an automated response governed or even initiated by machines rather than people.
Combined with the instantaneous strike capabilities of cyberwarfare, peer competitor countries could find the technology both a useful tool and source of immense anxiety. One not limited by the fears that have so far governed the use of ICBMs as war-opening weapons system. The potential consequences of developing and deploying hypersonic strike vehicles is something that the present day powers and emerging powers should give much thought to. Especially during the 100th anniversary of World War I. An immensely tragic conflict started in large part by recognition on the part of belligerents that maturing rail road technology and new national mobilization requirements meant that any nation that hesitated in the face of an enemy movement to war could find themselves overwhelmed with a speed unthinkable less than a generation earlier.