Lockheed Martin to supply US Navy with ‘Conventional Prompt Strike’ hypersonic missiles

On Friday, the Pentagon announced Lockheed Martin has been awarded a contract worth more than $2 billion in total to deliver new hypersonic missiles for use aboard the Navy’s Zumwalt-class guided missile destroyers. These new high-speed missiles are expected to enter service very rapidly, with Lockheed Martin projecting they’ll be fitted on the stealthy warships as soon as the “mid-2020s.”

The new missiles, known as the Conventional Prompt Strike system, are hypersonic boost-glide weapons similar to those already in service for China and Russia, though the American government has committed to fielding only conventionally armed, or non-nuclear, hypersonic weapons.

“Lockheed Martin continues to advance hypersonic strike capability for the United States through this new contract,” said Steve Layne, vice president of Hypersonic Strike Weapon Systems at Lockheed Martin. “Early design work is already underway. Our team looks forward to supporting the warfighter by providing more options to further protect America at sea.”

Hypersonic missiles are fast, but that’s not what makes them special

Modern hypersonic missiles are often characterized as weapons that are capable of sustaining speeds in excess of Mach 5, or right around 3,836 miles per hour. But the truth is, missiles have been traveling at those speeds since 1949, when American engineers modified a recovered Nazi V-2 to incorporate a second-stage rocket motor in a program called Project Bumper. What actually makes modern hypersonic missiles special is their ability to maneuver unpredictably at those high speeds.

All modern ballistic missiles reach hypersonic velocities as they close with their targets, but because they travel along high-arcing ballistic flight paths that are fairly predictable, air defense systems are able to calculate their trajectory and launch interceptors to meet the missile somewhere along its path.

Hypersonic weapons, on the other hand, can change course, rendering those predictive calculations moot, dramatically reducing the chances of a successful intercept.

Modern hypersonic weapons tend to come in one of two forms: hypersonic boost-glide vehicles (sometimes called Hypersonic Glide Vehicles, or HGVs), and hypersonic cruise missiles. These two types of missiles actually have very little in common, but are grouped together because of the nature of the challenge they represent for air defenses.

Hypersonic cruise missiles fly at low altitudes using air-breathing jet engines like supersonic combustion ramjets. You can learn more about them in our in-depth coverage of scramjet-powered missile tests here.

Hypersonic glide vehicles, on the other hand, don’t rely on exotic propulsion systems for their speed, and instead could be thought of as a sort of continuation of longstanding ballistic missile technology.

Conventional Prompt Strike: The Navy’s first hypersonic missile

Artist render of an HGV separating from its rocket booster.

This new weapon Lockheed Martin will be integrating into the Navy’s Zumwalt-class destroyers falls into the Hypersonic Glide Vehicle (HGV) category of hypersonic missiles. That means that it’s carried aloft via a conventional rocket booster, not unlike previous ballistic missiles, but it flies along a suppressed ballistic flight path that’s lower than traditional ballistic missiles.

Once it reaches the appropriate speed and altitude, the HGV separates from the rocket booster and begins its unpowered descent toward its target, using a lifting-body design that may incorporate either moving control surfaces or Reaction Control System (RCS) thrusters for maneuver control. Despite lacking any means of propulsion once separated from the rocket booster, HGVs can reach incredible speeds — potentially even in excess of Mach 20 — delivering not just an explosive warhead, but an incredible amount of kinetic energy, upon impact.

Because of this combination of maneuverability and speed, HGVs like the Conventional Prompt Strike (CPS) weapon are considered to be all but indefensible for current state air defense systems.

Work on the Conventional Prompt Strike program began all the way back in 2003, though the effort was under a different banner at the time — “Prompt Global Strike.” The premise was simple: develop the ability to strike targets anywhere in the world with a conventional warhead in under an hour. The missile being developed for the Conventional Prompt Strike program is shared with the Army’s ground-launched Long Range Hypersonic Weapon (LRHW) effort.

The rationale behind developing this capability was borne out of America’s ever-present need for rapid force projection. America currently maintains military installations around the world, bolstered by deployed carrier strike groups and cruise-missile submarines, to allow for a rapid response to any sort of non-nuclear threat. But in the modern era, force restructuring and new areas of potential conflict could limit America’s ability to quickly reach far-flung troubled spots. Conventional Prompt Strike aims to offset the tyranny of distance by providing the U.S. military with the means to rapidly engage targets anywhere on the globe, regardless of the pre-positioning of forces.

As discussed in the Congressional Research Service’s 55-page breakdown of the Conventional Prompt Strike program published in 2021, these new high-speed missiles could be leveraged in a wide variety of potential situations, such as:

A near-peer competitor had used its emerging counter-space capability to destroy a U.S. satellite.
The United States wanted to destroy a package of special nuclear materials that a terrorist organization had shipped to a neutral country.
A small package of weapons of mass destruction was located temporarily in a rural area of a neutral country.
The leadership of a terrorist organization had gathered in a known location in a neutral country.
A rogue state armed with a nuclear weapon was threatening to use that weapon against a U.S. ally.

Logically speaking, the most potent use of this fast-moving missile would be against targets in time-sensitive locations, where the window of opportunity for a strike is extremely finite.

The Zumwalt-Class guided missile destroyers will be the first to receive Conventional Prompt Strike Capabilities

The Zumwalt class of guided missile destroyers was originally intended to serve as a replacement for the Navy’s workhorse Arleigh Burke-class destroyers, but rising costs and repeated setbacks eventually led to the class’ cancellation after just three vessels were produced. These stealth destroyers are downright massive, stretching more than 610 feet in length and nearly 81 feet across, more than a hundred feet longer than your average Arleigh Burke.

But despite their size, a high degree of automation allows the Zumwalt class to sail with a crew of just 160, as compared to later iterations of the Arleigh Burke, which sail with a crew of 380. Likewise, although the Zumwalt-class are the largest destroyers in the world, their stealth technology reportedly results in a radar return similar to that of a small fishing boat.

However, the entire class was designed around the “Advanced Gun System” effort, which aimed to field a new kind of 155mm gun that fired extremely expensive munitions called the Long Range Land Attack Projectile (LRLAP), and at one point there was even discussion of mounting a high-powered electro-magnetic rail gun on the class. When neither of these concepts manifested, however, this abbreviated class of low-observable warships was left without any truly substantial combat capability.

However, incorporating the Conventional Prompt Strike hypersonic missile into the platform could bring the Zumwalt class out of the proverbial doghouse, making them some of America’s most potent forms of force projection for some time to come. The combination of the vessel’s stealth profile and the incredible new capability offered by the CPS weapon system could make Zumwalt destroyers a force to be reckoned with on the world stage.