October 28, 2022:
Ukraine wants longer range guided rockets from the United States. The United States still refuses but the pressure is building as it become more obvious that the lack of longer-range (300 kilometers) missiles like ATACMS (Army Tactical Missile System) could be decisive, just as the smaller GMLRS (Guided Multiple Launch Rocket System) missile and its 80 kilometers range have been. There are other longer-range missiles available from the United States. There is a longer range GMLRS called ER MLRS with a range of 150 kilometers. The manufacturer has offered to send pre-production ER GMLRS to Ukraine but that requires permission from the U.S. government.
Ukraine has been asking for the ATACMS since June. It is, like GMLRS, carried and launched from the HIMARS truck. There is also a successor to ATACMS called PrSM (Precision Strike Missile) with a range of 650 kilometers. This one, like ER GMLRS, are still in development but are ready for mass production and some development missiles are available for Ukraine to use.
GMLRS, ER GMLRS, ATACMS and PrSM are all developed and produced by Lockheed Martin. GMLRS has been a big seller with about 50,000 missiles produced so far. Ukraine is responsible for depleting American and other NATO nation stockpiles,
All four can be carried and launched from the HIMARS vehicle. All three variants are more expensive than GMLRS, which cost about $150,000 each. ER GMLRS doubles that price and PrSM cost about $1.5 million each. While HIMARS carries six GMLRS or ER GMLRS, it can only carry one ATACMS. The new PrSM is smaller that ATACMS but larger than GMLRS. That means HIMARS can carry two PrSMs.
The original ATACMS had a range of 300 kilometers and a 230 kg (500 pound) warhead. A planned replacement for ATACMS called Deepstrike was renamed Precision Strike Missile or PrSM. Deepstrike was designed to be capable of hitting targets 500 kilometers away and has more capable guidance system features. This includes an optional guidance system that allows PrSM to hit moving targets, especially ships at sea. The U.S. Navy is interested in this because the Marine Corps has already demonstrated that HIMARS can launch GMLRS from the deck of an amphibious assault ship, which has a flight deck similar to the larger nuclear carriers.
The ATACMS is a 610mm ballistic missile that is no longer produced. Its 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. It was not difficult to then 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 most bullets. 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 (which can be 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 use. In addition to those used in combat about three percent were fired for training or testing.
Ukraine demonstrated that using longer-range missiles in HIMARS are much more useful in a near peer war than previously thought. The main reason American leaders give for not providing Ukraine with longer range missiles is the risk of the war escalating. Russia has already done that and the Ukrainians make the case that the longer-range missiles will help speed the end of the war.