June 2, 2024: The war in Ukraine gave the United States an opportunity to use its older, near their expiration date, ATACMS (Army Tactical Missile Systems) rockets rather than spending a lot of money safely disposing of them. Ukrainian weapons experts knew the risks of firing these older rockets was low for the users and Ukraine needed all the long range firepower they could get. In late 2023 Ukraine received dozens of the ATACMS missiles and in early 2024 received some of the updated ATACMS missiles with longer range. By 2024 the replacement for ATACMS called Deepstrike was ready to enter service. The war in Ukraine led to a few Deepstrike missiles being sent to Ukraine to see how the new missile would perform in combat. Deepstrike is a thinner rocket so that two can be fit into a MLRS container that currently holds one ATACMS. Deepstrike has a longer 500 kilometer range and a more capable guidance system.

Meanwhile the Americans were already upgrading their ATACMS rockets before the Russian invasion of Ukraine in 2022. In mid-2018 the U.S. Army increased its spending on SLEP (service-life-extension program) work on its older MGM140 ATACMS artillery rockets. Nearly 4,000 ATACMS had been built since the missile entered service in the late 1980s. In the late 1990s a longer range, GPS guided version was introduced but by then most of the current ATACMS missiles were built and production slowed to very little by 2007. The SLEP program refurbished and upgraded the older, shorter range, 165 kilometer unguided ATACMS so they have features of the latest models. The SLEP will produce a like-new guided missile with a ten year shelf life and a 250-300 kilometer range, depending on the weight of the warhead.

Older ATACMS underwent SLEP at the rate of 300-500 a year until all of the ATACMS stockpile was refurbished. That meant several thousand SLEPed ATACMS that could accept new warheads with new features like ground penetration to destroy underground facilities and more capable guidance systems.

The ATACMS is a 610mm ballistic missile that fits in the same size container that normally holds six 227mm MLRS rockets on a HIMARS truck. The latest upgrades have been to the guidance system. In 2017 ATACMS was given the ability to hit moving targets, specifically ships at sea. ATACMS has sufficient range for that and the U.S. pioneered the development of terminal guidance systems for ballistic missiles in the 1970s the Pershing mobile missile. Since then the U.S. has developed similar guidance systems so that high-speed missiles can hit moving targets. So it was not a difficult feat to develop a terminal guidance system for ATACMS that searches for a certain size ship and heads for it while moving at more than a thousand meters a second, which is faster than a very speedy bullet. The ATACMS guidance system has also received a proximity detonation capability so that it can be programmed to explode in the air above a target. All the current ATACMS needs is the GPS coordinates of the moving target on land or sea. Since max flight time at max range is only a few minutes it is easy to predict where the moving target will be based on aerial, satellite, or sonar detection. It takes less than a minute to update the guidance system and launch. If nothing else this will give potential naval foes something more to worry about and be a popular export item as well.

Most current ATACMS are armed with a 227 kg (500 pound) high explosive warhead. The U.S. used over 700 ATACMS, most of them in Iraq and Afghanistan combat operations and their performance was excellent, especially the guided ones. Nearly 4,000 ATACMS have been built since the mid-1980s and about 70 percent are still available for another upgrade. In addition to those used in combat about three percent were fired for training or testing. ATACMS currently use GPS guidance to hit targets up to 300 kilometers away.

When the U.S. Army first introduced ATACMS in the late 1980s it designed cluster bomb warheads that distributed lots of smaller bomblets because the first ATACMS were unguided. While these worked, there was always a problem with some of the bomblets not self-destructing and later going off when civilians, or American troops, came along. As a result cluster bomb warheads were not popular. Then, when a version with GPS guidance and a single 227 kg high explosive warhead was introduced, it proved very popular. ATACMS currently cost about $1.3 million dollars each. A 227 kg JDAM dumb bomb with a GPS guidance kit attached costs about $40,000, although you can at least double that to cover the expense of operating the jet fighter or bomber that delivered it. This makes ATACMS sort of like the popular 227 kg JDAM smart bomb used by the air force but not requiring an aircraft to deliver it. ATACMS can be used in any weather conditions at any time and on short notice. It also travels a lot faster than any aircraft. Despite the growing use of inexpensive UAVS to deliver smaller JDAMS or even smaller 49 kg Hellfire missiles or 120 kg (280 pound) SDB (small diameter bombs) the ATACMS is always available to get something on the target right away.

Another advantage of ATACMS is the ability to quickly move it and its launcher by air to anywhere in the world. This is because of HIMARS. Only costing about $3 million each, these smaller, truck mounted MLRS (HIMARS) rocket launcher systems carry only one, six rocket (or one ATACMS) container. The 12 ton HIMARS truck can fit into a C-130 transport, unlike the 22 ton tracked MLRS that carried twelve missiles in two pods. HIMARS was much cheaper to operate. The first HIMARS entered service in 2005, about a year after GPS guided rockets did. HIMARS proved more effective and popular than expected. HIMARS can carry one ATACMS but most of the time carries more and sometimes does. Now it can also carry two of the thinner Deepstrike missiles that are replacing ATACMS.