U.S. to Start Flight Testing PrSM Increment 4 Missile With Range Exceeding 1,000 km in 2026

Lockheed Martin plans to begin flight testing the Precision Strike Missile (PrSM) Increment 4 for use with HIMARS launchers. Testing is planned to start in fall 2026, with the PrSM expected to exceed 1,000 kilometers.

Hartpunkt reported this news.

According to Lockheed Martin, the development milestone was enabled by significant progress on a combined propulsion system integrating a solid-fuel rocket motor with a ramjet engine.

During a recent test, the missile under development successfully demonstrated a transition from booster propulsion to ramjet operation on a test stand.

The manufacturer claims that the new propulsion architecture enables a range of over 1,000 km. PrSM Increment 4 remains compatible with existing HIMARS and M270 launchers, enabling long-range precision strike capability without changes to launch platforms or logistics.

PrSM ballistic missile family

The Precision Strike Missile (PrSM) is a family of long-range ballistic missiles with a range exceeding 500 km, developed to replace ATACMS in the U.S. Army arsenal.

At 4 meters in length and 430 mm in diameter, the PrSM is approximately half the diameter of the ATACMS, allowing a HIMARS or M270A2 launcher to carry twice as many missiles.

However, the missile carries a significantly smaller warhead than ATACMS — about 91 kg. This is intended to be offset by high-precision guidance.

The system is being developed in incremental blocks, allowing rapid fielding of a baseline capability followed by iterative upgrades.

Increment 1 features an inertial navigation system combined with jam-resistant GPS guidance and a range of up to 500 km. The missiles entered mass production in July 2025 and were actively used during the war with Iran.

Increment 2 is designed to add passive radio-frequency and infrared seekers, enabling engagement with enemy radar systems and maritime targets. Initial flight testing began in March 2026.

Increment 3 focuses on warhead improvements, including cluster and concrete-penetrating warheads, as well as loitering-munition capability. No public timeline has been disclosed.

Increment 4 is expected to extend the range beyond 1,000 km without major changes to external dimensions.
Increment 5 will explore launch from unmanned platforms.

In fall 2025, Lockheed Martin stated it aims to produce up to 400 PrSM missiles annually.