Navy photo

    Launch of Army-Navy Common-Hypersonic Glide Body (C-HGB) in Hawaii on March 19, 2020.

WASHINGTON: How far can the Army’s hypersonic boost-glide missile — and, probably, its Naval variant — actually go? Consider this Pacific nightmare: China invades Taiwan, but all of America’s allies refuse to let the US use their territory or airspace. Long-Range Hypersonic Weapons, based on US soil in Guam, could still strike Chinese troops besieging Taipei.

Conversely, in China’s nightmare scenario, where US allies do let American missile units use their soil, LRHW batteries in Taiwan, Japan, or South Korea could strike targets more than one thousand miles inside Chinese territory. What’s more, the Navy version of the LRHW, called Conventional Prompt Strike, could launch from submarines or ships at sea anywhere in the Pacific.

“The Long Range Hypersonic Weapon provides a capability at a distance greater than 2,775 km,” an Army spokesman told me. That’s about 1,725 miles – at a minimum. The “greater than” leaves the door wide open for a significantly longer range than that.

That Army statement came after years of silence on the subject, weeks of pestering by Breaking Defense, and at least one high-level discussion among the interservice “board of directors” coordinating hypersonics programs.

Why would the Navy need to be consulted? While the Army’s statement only applies to the Army version, the land-based LRHW, the Navy’s sea-launched Conventional Prompt Strike weapon uses the identical rocket booster and hypersonic “glide body,” just packaged for launch from ships and subs instead of trucks. So it’s hard to imagine the range could be much different. If the Army version reaches 1,725-plus miles, the Navy version almost certainly does too. 

Google Maps image

With a range “greater than 2,775 km” (1,725 miles), the Long-Range Hypersonic Weapon could reach Taiwan from Guam.

For its part, the Air Force is developing multiple types of hypersonic weapons to launch from planes, which requires a different engineering approach and will result in different ranges.

Now, naval vessels and strategic bombers are obviously much more mobile than truck-borne launchers, and they can fire from international waters and airspace, without worrying about allies. But land-based launchers are cheaper – they’re just trucks, not jets or subs – and can hide from enemy strikes amidst terrain – which is not possible in the empty air or flat ocean. So the Army and its advocates argue its missiles can play an important supporting role and complement Navy and Air Force weapons.

That argument is now up for fierce debate as the Pentagon’s budget tightens.

Sydney J. Freedberg Jr. graphic from Army data

Breaking Defense graphic from Army data. KEY: ERCA = Extended Range Cannon Artillery. GMLRS-ER: Guided Multiple Launch Rocket System – Extended Range. PrSM = Precision Strike Missile. MRC = Mid-Range Capability. LRHW = Long Range Hypersonic Weapon.

Family of Fires

From the Army perspective, the LRHW is the apex predator of a whole family of new Long Range Precision Fires (LRPF). While LRHW is the longest-ranged, fastest-flying, and most capable, it’s also the most expensive. So hypersonics will be reserved for the highest-priority targets, while shorter-ranged weapons take on the vast majority of threats.

As we’ve reported previously, under the Army’s artillery plan, the higher the headquarters, the longer-ranged the weapons it will control:

  • Theater commanders in both Europe and the Pacific will gain control of Multi-Domain Task Forces equipped with both the Long-Range Hypersonic Weapon, with range “greater than 2,775 km” (1,725 miles) and the Mid-Range Capability, with a range of “around 1,800 km” (ca. 1,120 miles). LRHW and MRC will each field a battery of combat-capable prototypes in 2023.
  • Corps commanders will get the new Precision Strike Missile (PrSM), with a range of “over 500 km” (310 miles). PrSM completed its fourth test flight today, exceeding 400 km. Future variants of PrSM have the potential to triple its range.
  • Division commanders will get the new Extended Range Cannon Artillery (ERCA), an armored howitzer with an extra-long barrel and high-powered propellant that can fire rocket-boosted, precision-guided shells about 70 km (43 miles). Future ramjet ammunition might double that.
  • Brigade commanders will retain their existing 155 mm howitzers, but those will be able to fire the same XM1113 Rocket Assisted Projectile (RAP) as ERCA, which from their shorter barrels can reach about 40 km (25 miles).

These weapons will depend on targeting data from long-range sensors – Army, joint, and intelligence agency – shared over a Joint All Domain Command & Control (JADC2) network. And they’ll rely on artificial intelligence to swiftly spot targets, prioritize among them, and propose the best weapon to fire.