The U.S. Army continues to invest in upgrades to its Cold-War era Patriot missile system in the proposed fiscal 2019 budget, requesting about $1.6 billion in upgrades to increase its range and lethality.

Since it was fielded in the mid-1980s, the Phased Array Tracking to Intercept of Target, or Patriot, system has been the Army's air-defense workhorse, designed to counter tactical ballistic missiles, cruise missiles, and advanced aircraft.

The latest improvement to the Patriotis the Missile Segment Enhancement, an upgrade to Raytheon's Patriot Advanced Capability 3, or PAC 3, missile.

The MSE, made by Lockheed Martin Missiles and Fire Control, adds improvements such as a dual-pulse, 11-inch diameter solid rocket motor, a thermally hardened front end, upgraded batteries, enlarged fixed fins and upgraded guidance software, according to the Army. These updates are intended to make it a more agile, lethal interceptor with extended range.

The Army plans to spend $1.1 billion to buy 240 MSE interceptors and 40 Patriot launcher modification kits which allow the launcher to fire the MSE as well as other missiles, according to Davis Welch, deputy director of Army Budget.

The Army also plans to spend $526 million -- $313.2 million out of procurement, $185.7 million out of research, development, testing and evaluation and $27.7 million out of spares -- to continue to improve the software and other features on existing PAC 3 missiles, according to budget documents.

This 2019 Patriot request follows the trend from the service's 2018 spending plan, which budgeted about $1.1 billion MSE missiles and $681 million on Patriot system upgrades.

All told, the Army plans to spend $5.1 billion on missile procurement programs in fiscal 2019, compared to last year's request of $3.9 billion.

Part of that request buys 9,450 Guided Multi Launch Rocket Systems, or GLMRS, compared to last year's purchase of 6,084. The budget request also purchases 404 Army Tactical Missile Systems over last year's 122 -- that's a 62 percent increase in the ATACMS Service Life Extension program, Welch said.

-- Matthew Cox can be reached at matthew.cox@military.com.