SADARM (Search And Destroy Armor Munitions)-equipped 155mm artillery shells proved so successful in Ukraine against armored vehicles that over 20,000 of these shells were provided to the Ukrainian forces in the last five months. Unlike the United States, Germany produced these shells mainly for use against local threats, like Russia. The Ukraine war saw the Russians using thousands of tanks and losing most of them to Ukrainian troops armed with Western anti-tank weapons featuring top-attack capability.
SADARM tech was developed during the 1980s, perfected in the 1990s and when it was sent to Ukraine, it turned towed and self-propelled artillery into very effective anti-vehicle weapons. SADARM was able to destroy all sorts of vehicles and, because of flaws in tank design and protection, especially Russian tanks. Ukraine asked for all the SADARM shells NATO nations could provide and most European NATO members sent nearly all SADARM shells they had.
Germany, Britain, Italy and Sweden manufacture 155mm artillery shells carrying two each Sense and Destroy Armor Munitions. Originally called SADARM munitions by its American developer (Textron), it had completed development when the Cold War suddenly ended in 1991. SADARM was not as effective as expected and the 155mm version was canceled in 2001. The U.S. Air Force has more success with the SADARM submunitions used in the CBU-105 cluster bomb (40 submunitions per half-ton cluster bomb) because a bomb undergoes much less stress when used than an artillery shell. The air force and six export customers purchased hundreds of these bombs but sales were not high enough to keep CBU-105 in production after 2017.
Meanwhile the U.S. Army noticed the success of an improved German SADARM shell called SMART as well as the similar Swedish Bonus. Both entered service in 2000 and both were successful as “Improved SADARM”. The U.S. Army began ordering BONUS shells in 2018 and ordered more in 2020.
BONUS is described as a fire and forget guided 155-millimeter ammunition designed for destroying armored targets. BONUS was a joint project by Britain, France and Sweden with the Swedes taking the lead in production. BONUS can be fired from standard NATO 155mm artillery and has a maximum 35-kilometer effective range. The round carries two submunitions, each with their own multiband IR (heat) sensors backed by laser radar. BONUS uses small winglets to slow its descent rather than small parachutes that are used in earlier similar submunitions, like the German SMART shell. The parachutes are easier to spot and more expensive and complex to use.
The submunitions separate from the shell over the target location (using a time-on-target fuze) about 175 meters above the target areas and scan for targets. Each warhead can scan about 32,000 square meters and hit even moving targets within that area. The destruction is achieved by an Explosively Formed Penetrator (EFP) able to punch through more than 130 mm (five inches) of armor. This doesn’t seem like much but the tank armor is strongest at the front and not at rear or top. The only defense against this “top attack'' EFP is APS (Active Protection Systems) such as Trophy, but even these have difficulty dealing with things like EFPs. The APS systems work great against HEAT warheads because these disperse cumulative streams of superheated gasses, but not against molten metal projectiles formed by an EFP. Moreover, thanks to two submunitions per shell, the artillery halts for a shorter time to fire, so they are less likely to get caught by enemy counter-battery fire. The major defect of SADARM shells is that they are more expensive than GPS guided Excalibur shells.
Each submunition weighs 3.4 kg (7.5 pounds) and uses 945 g (2.08 pounds) of Octol explosives, which was designed to effectively form the self-forging penetrator. Most of the submunition weight goes to the sensors (including batteries) and design elements that slow descent and rotate the sensors to find a target. The use of batteries and various types of explosives in a SADARM shell means they have a limited shelf life. After twenty years or so, SADARM shells must be refurbished or disposed of. Many of the European SADARM shells were approaching their expiration date so it made sense to send all the old, but still functional, ones to Ukraine. Now these SMART and BONUS shells must be replaced. Germany found that many of the key components were no longer available and had to invest over hundred million dollars to revive production. Initially, Germany has ordered 10,000 new SMART shells at a cost of $81,000 each. Because of the components problem it will take five years or more before production is completed. The only new SADARM shell is the Italian V9lcano 155 shell. Several hundred of these were sent to Ukraine because the Volcano shell is currently completing development. Ukraine will get to test the new shell. There are two versions of Volcano 155; one that is similar to SMART and BONUS but with a range of up to 50 kilometers. The Volcano 155 GR has a range of up to 70 kilometers and includes GPS guidance to ensure the shell arrives at the target location. If the war goes on into 2023, the Volcano GR may reach Ukraine.
These SADARM shells plus the effective Ukrainian use of battlefield surveillance UAVs (most of them developed and produced by Ukraine) were a key factor in Russia losing so much territory in the last four months. Russia was forced to keep its armored vehicles away from the front line unless urgently needed. Even then, there were not enough Russian armored vehicles or artillery (self-propelled or towed) left to use. Ukraine used regular and some GPS artillery shells to hammer Russian supply storage sites, towed artillery, supply trucks and headquarters within range. American satellite surveillance also provides some target information, but not as quickly as Ukrainian UAVs and frontline troops.
The original American M898 SADARM dates back to the late 1970s when the army started to look for a “smart” anti-armor 155 mm projectile. About a decade later SADARM had been developed and prototypes built but budget restrictions in 1990 slowed down the program. In 1993 the first tests were unsatisfactory because SADARM hadn't been able to hit a moving target and overall accuracy was poor. The manufacturer promised to improve the technology, and a year later the program was approved for limited low-rate production. Unfortunately for SADARM the later (1995, 1998 and 1999) tests showed only a little improvement. In all trials, the SADARM struggled to get an 80 percent reliability rate. This together with significant cost overruns were reason enough to end production in 2001. This failure did not mean the end of the SADARM SFW submunition technology, which was subsequently adopted by the U.S. Air Force as well as the developers of the SMART and BONUS shells who achieved effective reliability in the late 1990s. The submunition was always meant to be carried by a wide variety of projectiles including MLRS rockets, mortar shells and cluster bombs.
Reliability of the SADARM submunition improved enough to work as the payload of CBU-105 half ton cluster bombs. Each of these bombs carries and disperses 40 submunitions Each SADARM submunition has its own radar and heat sensor that searches for armored vehicles below and destroys them. SADARM sensors can search and attack vehicles within an area of roughly 150 x 360 meters as they slowly descend. The self-forging metal projectile used by the SADARM submunition punches through the thinner armor on the top of the vehicle. If a target is not found, SADARM self-destructs. CNU-105 has not shown up in Ukraine because the Russians rarely use large enough concentrations of armored vehicles to justify use of CBU-105. Ukraine prefers to save its aircraft for air defense and use artillery and guided rockets for distant targets.
The first use of the CBU-105 was in early 2003, when a B-52 dropped six of them on an Iraqi army column moving south from Baghdad. Most of the vehicles were later found destroyed. Since then, there have been several export customers for CBU-105 and the U.S. Air Force still has them stockpiled for future use even though production ceased in 2017.
The Russians have a version of their own, SPBE-D, for sale to anyone who can pay for it. The American CBU-105 is preferred because the United States pioneered the technology, and demonstrated it could work in combat. India faces a large force of Pakistani tanks, and CBU-105 is an inexpensive and quick way to destroy lots of armored vehicles.
Russia eventually responded to the SADARM submunition threat by developing a new generation of ERA (Explosive Reactive Armor) that now covers the top of the turret and engine compartment of their tanks. In theory the new ERA should protect against SFW or at least reduce SFW effectiveness. The Russian ERA does not appear to be working against SFW and that has terrorized armored vehicle crews who now feel very vulnerable when within range of Ukrainian artillery. This often leads to many armored vehicles being abandoned by their crews when it appears they are under attack by SADARM. Ukrainian forces have captured hundreds of tanks and other armored vehicles and put them to use with a new paint job and Ukrainian crews.