HIMARS Modifications

The HIMARS Modifications program, as detailed in Line Item 6580C67501 of the Army's FY2026 Missile Procurement budget, is focused on sustaining and modernizing the M142 High Mobility Artillery Rocket System (HIMARS) fleet. The overarching goal is to ensure operational reliability, safety, and crew survivability while addressing obsolescence issues that affect critical system components. This program supports the Army's Long Range Precision Fires modernization effort and enhances the capability of HIMARS to deliver precision strike, operational shaping fires, counterfire, and close support missions. The modifications are essential for maintaining the fleet's relevance in multi-domain operations and for supporting homeland defense and emergency response missions.

MOD 1 targets safety, operational, chassis, fire control system, and Command, Control, Communications, Computer, and Intelligence (C4I) obsolescence across the HIMARS fleet. Objectives include updating Interactive Electronic Technical Manuals (IETMs), procuring diagnostic and mock-up trainers for operator and maintainer training, and implementing systems engineering modifications to the carrier, launcher loader module, and fire control system. A significant aspect of MOD 1 is the Common Fire Control System (CFCS) obsolescence mitigation, which replaces outdated components and transitions the board layout from through-hole to modern surface mount technology. This ensures continued CFCS production and support.

MOD 2 focuses on the procurement and installation of CFCS retrofit kits and Launcher Adapter Group (LAG) kits for the HIMARS fleet. The CFCS replaces the obsolete Universal Fire Control System (UFCS), enabling the launch of all current and future Multiple Launch Rocket System Family of Munitions (MFOM), such as Guided MLRS, ATACMS, Extended Range GMLRS, and Precision Strike Missile. The CFCS provides a more intuitive user interface common to both HIMARS and MLRS launchers, which reduces training and maintenance costs. MOD 2 funding supports the procurement and fielding of CFCS kits and LAG kits at a three-to-one ratio of launchers to LAGs, facilitating fleet-wide modernization and obsolescence mitigation.

MOD 3 addresses Assured Position, Navigation, and Timing (APNT) requirements by enhancing anti-jam capabilities for both UFCS- and CFCS-equipped launchers. For UFCS-equipped HIMARS, the integration of the Digital Anti-Jam Receiver (DIGAR) provides robust protection against GPS jamming. For CFCS-equipped launchers, MOD 3 includes the implementation of anti-jam antennas (DIGAR) and upgrades to the NAVSTRIKE-M GPS receiver, which will deliver M-Code capability in future years. Procurement includes DIGAR kits and APNT LAG kits, with future plans to acquire NAVSTRIKE-M kits as development continues. These upgrades ensure compliance with statutory requirements and enhance the fleet's resilience against electronic warfare threats.

The program's funding profile for FY2026 supports the acquisition of modification kits, training devices, and obsolescence mitigation measures. Procurement quantities for each modification item are determined by fleet requirements and the goal of achieving pure-fleeting with modernized systems. The modifications are implemented organically by the Field Artillery Launchers Product Office, with manufacturers located at various sites and administrative and production lead times specified for each kit type.

Justification for the HIMARS Modifications program is rooted in the need to maintain fleet readiness, address aging and obsolete components, and ensure interoperability with current and future munitions. The program also supports statutory mandates for homeland defense and military support to civil authorities. By investing in these modifications, the Army aims to extend the service life of the HIMARS fleet, enhance operational effectiveness, and reduce long-term training and maintenance costs.