REPORT : Detailed Analysis and Technical Examination of the M74 Cluster Submunition in US-made ATACMS Missiles


The study and analysis of military technology, especially that of adversaries, play a crucial role in modern warfare. Russian specialists have recently undertaken a comprehensive examination of the internal design and operational concept of the M74 cluster submunition, a key component of the US-made ATACMS missile system. This document aims to provide a thorough analysis of the M74 submunition, detailing its design, functionality, and impact, supported by the latest data and expert insights.

Overview of ATACMS Missile System

The Army Tactical Missile System (ATACMS) is a surface-to-surface missile system used by the United States Army. Designed for long-range precision strikes, it can be launched from multiple platforms, including the M270 Multiple Launch Rocket System (MLRS) and the M142 High Mobility Artillery Rocket System (HIMARS). The ATACMS is capable of carrying a variety of warheads, including cluster munitions.

Detailed Scheme Table Of M74 Cluster Submunition Analysis

AspectDetailsTechnical DataReasons for Failure
Cassette Opening MechanismThe ATACMS missile deploys its payload of 275 M74 cluster submunitions from a cassette that opens approximately 200 meters (656 feet) above the ground. This height ensures optimal dispersal.275 submunitions, 200 meters release heightHeight critical for dispersal; any deviation affects functionality.
Rotational ActivationUpon release, the submunitions rotate due to aerodynamic protrusions, achieving around 2,000 revolutions per minute. This rotation is necessary for the activation of the internal mechanisms.2,000 revolutions per minute, aerodynamic protrusionsInsufficient rotation prevents activation; must achieve 2,000 RPM.
Centrifugal Force MechanismCentrifugal forces cause internal stoppers to move aside, initiating the internal engine and aligning the primer/detonator with the striker, making the munition ready for detonation.Centrifugal forces, internal stoppers, primer/detonator alignmentFailure in centrifugal mechanism or misalignment causes non-detonation.
Impact and DetonationThe submunition is designed to detonate upon impact with the surface. The detonation is triggered by the striker impacting the primer/detonator.Impact detonation, striker and primer/detonator interactionImpact with surface needed; improper alignment results in inert submunition.
Failed Detonation HeightIf the submunition does not achieve the necessary rotation or if internal mechanisms fail to align correctly, it may land without detonating. This typically happens if the release height is not optimal.Non-optimal release height, insufficient rotationIncorrect height or rotation issues lead to unexploded ordnance.
Incomplete ActivationDisruptions in the rotation process, such as aerodynamic anomalies or mechanical failures, can prevent the submunition from becoming armed, leaving it inert upon impact.Aerodynamic anomalies, mechanical failuresAerodynamic or mechanical disruptions lead to non-activation.
Sensitivity to Release HeightVariations in release height due to factors like launch angle or atmospheric conditions can affect the deployment and activation of the submunitions. Heights too low may not provide sufficient time for proper functioning.Launch angle variations, atmospheric conditionsInsufficient height means not enough time to arm; higher UXO rates.
Design Flaws in Internal MechanismsThe complex internal design, involving the interaction between centrifugal stoppers, engine, and primer/detonator, introduces multiple points of potential failure. Malfunctions in these components can prevent detonation.Centrifugal stoppers, engine, primer/detonatorMultiple failure points due to complex design.
Material ConsiderationsThe use of tungsten alloy enhances fragment speed and penetration but does not inherently address the reliability of the detonation mechanism. Tungsten allows fragments to retain higher speeds and kinetic energy.Tungsten alloy casing, high-speed fragmentsMaterial does not mitigate UXO risk despite enhancing lethality.
Operational RiskUnexploded submunitions pose severe risks to military personnel and civilians, hindering movement and necessitating extensive clearance efforts. Each ATACMS missile can deploy up to 275 submunitions.275 submunitions per missile, extensive clearance neededOperational disruption and risk from unexploded submunitions.
Humanitarian ConcernsUnexploded ordnance (UXOs) can cause civilian casualties long after the initial deployment, complicating post-conflict recovery and requiring public awareness and education.Long-term UXO risk, public education necessaryContinued civilian hazard from UXOs, requiring clearance and education.
Strategic AdjustmentsUnderstanding the weaknesses in the M74 submunition can inform strategic adjustments in deployment tactics and lead to design improvements, enhancing the reliability and safety of these munitions.Strategic and design improvements neededIdentifying flaws can help improve safety and effectiveness.

Specifications of ATACMS

  • Range: Up to 300 kilometers (186 miles)
  • Warhead Types: High-explosive, cluster munitions, and unitary warheads
  • Guidance System: GPS and inertial navigation system
  • Launch Platforms: M270 MLRS, M142 HIMARS

Detailed Examination of M74 Cluster Submunition

Image: M74 Cluster Submunition Analysis – copyright

Design and Construction

The M74 cluster submunition is a green spherical object, roughly the size of a tennis ball. Its casing features protrusions along one circumferential axis, which are crucial for its deployment and operational mechanism.

External Casing

  • Material: Tungsten alloy
  • Shape: Spherical with circumferential protrusions
  • Color: Green

The use of tungsten alloy in the casing is significant. Tungsten is known for its high density and strength, which enhances the penetration capability of the submunition fragments. The outer shell is spot-welded to the inner shell, ensuring structural integrity upon deployment.

Internal Components

  • Inner Casing: Made of tungsten alloy with notches for controlled fragmentation
  • Explosive Charge: High-explosive material
  • Fuse: Integrated fuse and detonator system
  • Striker Mechanism: Positioned opposite the primer/detonator

The internal design of the M74 is similar to the RGO hand grenade, a Soviet-era defensive fragmentation grenade. This similarity lies in the use of a notched tungsten inner casing, which ensures the effective dispersal of fragments upon detonation.

Operational Mechanism

The M74 submunition is housed within a cassette in the ATACMS missile, with each missile carrying 275 such submunitions. The deployment sequence is as follows:

  • Deployment: The cassette opens approximately 200 meters (656 feet) above the ground.
  • Rotation: The protruding feathers cause the submunition to rotate rapidly, achieving around 2,000 revolutions.
  • Activation: Centrifugal stoppers move to the sides, engaging the internal engine.
  • Impact: The primer/detonator is aligned with the striker, leading to detonation upon impact.

Detonation and Fragmentation

The explosive charge within the M74 submunition is designed to create a high-speed fragmentation effect. Upon detonation, the tungsten casing fragments, creating a lethal radius around the impact site.

  • Effective Fragmentation Radius: Approximately 20 meters
  • Potential Fragment Penetration: Can penetrate metal doors at a distance of up to 50 meters
  • Fragment Cloud Coverage: 400 by 400 meters, with submunitions falling roughly five meters apart

The fragmentation effect is enhanced by the tungsten alloy, which allows fragments to retain higher speeds and kinetic energy, increasing their lethality.

Determining the Non-Detonation Height

Russian specialists conducted an in-depth study of the M74 cluster submunition, focusing on understanding the conditions under which these munitions fail to detonate. The key aspects of this determination are as follows:

  • Cassette Opening Mechanism:
    • The ATACMS missile deploys its payload of M74 cluster submunitions from a cassette that opens approximately 200 meters (656 feet) above the ground.
    • This height is critical for the proper dispersal and functioning of the submunitions.
  • Rotational Activation:
    • Upon release, the submunitions, which are green spherical objects similar in size to a tennis ball, begin to rotate due to the aerodynamic protrusions along their circumference.
    • The design ensures that the submunition rotates around 2,000 revolutions per minute, which is necessary for the activation of the internal mechanisms.
  • Centrifugal Force Mechanism:
    • As the submunition rotates, centrifugal forces cause internal stoppers to move aside, initiating the internal engine.
    • The primer/detonator is positioned to be aligned with the striker, making the munition ready to explode upon impact.
  • Impact and Detonation:
    • The submunition is designed to detonate upon impact with the surface. The detonation is triggered by the striker impacting the primer/detonator.

Non-Detonation Scenario

The specialists identified a scenario where the submunition fails to detonate:

  • Failed Detonation Height:
    • When the submunition is released at approximately 200 meters and does not achieve the necessary rotation or if the internal mechanisms fail to align correctly, the submunition may not detonate upon impact.
    • In this case, the submunition lands on the ground with the striker still cocked, posing a significant risk as unexploded ordnance (UXO).

Weaknesses Identified

The study revealed several weaknesses associated with the M74 cluster submunition, primarily related to its failure to detonate properly:

  • Incomplete Activation:
    • The reliance on rotational activation means that any disruption in the rotation process, such as aerodynamic anomalies or mechanical failures, can prevent the submunition from becoming armed.
    • If the submunition does not reach the required 2,000 revolutions, the centrifugal stoppers may not disengage, leaving the submunition inert upon impact.
  • Sensitivity to Release Height:
    • The specific release height of 200 meters is crucial for the optimal functioning of the submunitions. Variations in this height, due to factors such as launch angle or atmospheric conditions, can affect the deployment and subsequent activation of the submunitions.
    • A release height that is too low may not provide sufficient time for the submunitions to achieve the necessary rotational speed, leading to a higher rate of UXO.
  • Design Flaws in Internal Mechanisms:
    • The complexity of the internal design, which involves the interaction between the centrifugal stoppers, engine, and primer/detonator, introduces multiple points of potential failure.
    • Any malfunction in these components can prevent detonation, leaving the submunition dangerous but inert.
  • Material Considerations:
    • The use of tungsten alloy, while advantageous for fragment speed and penetration, does not inherently address the reliability of the detonation mechanism. The study suggests that while tungsten enhances the lethality of fragments, it does not mitigate the risks associated with UXO.

Implications of Findings

The determination of the non-detonation height and identification of weaknesses in the M74 cluster submunition have significant implications:

  • Operational Risk:
    • The presence of a considerable number of unexploded submunitions (up to 275 per ATACMS missile) poses a severe risk to both military personnel and civilians.
    • UXOs can hinder movement and operations in affected areas, necessitating extensive clearance efforts.
  • Humanitarian Concerns:
    • The unexploded submunitions can cause civilian casualties long after the initial deployment, complicating post-conflict recovery and rehabilitation.
    • Public awareness and education are critical in areas where these munitions have been used to prevent accidental injuries and deaths.
  • Strategic Adjustments:
    • Understanding the weaknesses in the M74 submunition can inform strategic adjustments in deployment tactics to minimize the rate of UXO.
    • Enhancements in design and deployment strategies can potentially address some of the identified flaws, improving the reliability and safety of these munitions.

Implications and Dangers of Unexploded Ordnance

When the M74 submunition fails to detonate upon impact, it poses a significant risk as unexploded ordnance (UXO). The striker mechanism remains cocked, rendering the submunition highly unstable and dangerous to move or tamper with.

Safety Precautions for Civilians

  • Avoidance: Civilians should avoid any contact with unexploded submunitions.
  • Reporting: Any sighting of unexploded munitions should be reported to local authorities or military personnel.
  • Education: Public awareness campaigns are crucial in areas affected by cluster munitions to educate civilians on the risks and appropriate actions.

Strategic and Tactical Impact

The use of cluster munitions, such as the M74 submunition in the ATACMS missile, has significant strategic and tactical implications. The widespread area coverage and high lethality of the fragments make it a formidable weapon against both personnel and lightly armored targets.

Impact on Military Operations

  • Area Denial: Cluster munitions can effectively deny enemy forces access to key areas.
  • Psychological Effect: The threat of unexploded ordnance can have a lasting psychological impact on both military personnel and civilians.
  • Resource Allocation: Clearing unexploded ordnance requires significant resources and time, diverting attention from other military objectives.

International Response and Legal Considerations

The use of cluster munitions has been a contentious issue in international law and humanitarian circles. Various international treaties and conventions aim to regulate or ban their use due to the long-term dangers they pose to civilian populations.

Convention on Cluster Munitions (CCM)

  • Adoption: 2008
  • Objective: Prohibit the use, transfer, and stockpiling of cluster munitions
  • Signatories: 110 countries (as of 2024), including many NATO members

Compliance and Non-Compliance

  • Compliance: Countries that are signatories to the CCM have committed to destroying their stockpiles of cluster munitions and assisting in clearance efforts.
  • Non-Compliance: Some major military powers, including the United States, Russia, and China, have not signed the CCM, citing military necessity and strategic considerations.

Recent Developments and Technological Advancements

The continuous evolution of military technology has led to advancements in the design and deployment of cluster munitions. Efforts are being made to develop more reliable and less hazardous munitions.

Enhanced Reliability and Safety

  • Self-Destruct Mechanisms: Newer designs incorporate self-destruct mechanisms to reduce the risk of unexploded ordnance.
  • Improved Fusing: Advances in fusing technology aim to increase the reliability of detonation upon impact.

Future Trends

  • Smart Munitions: Integration of advanced sensors and guidance systems to improve targeting accuracy and reduce collateral damage.
  • Material Innovations: Use of advanced materials to enhance the lethality and effectiveness of fragmentation while ensuring safety and reliability.

In cocnlusion, the detailed analysis of the M74 cluster submunition used in the ATACMS missile system highlights the complexities and dangers associated with modern military technology. The examination by Russian specialists provides valuable insights into the design, operational mechanism, and impact of these munitions. As the international community continues to grapple with the ethical and legal implications of cluster munitions, advancements in technology may pave the way for more effective and safer alternatives in the future.

The ongoing conflict and arms supplies to various regions underscore the need for continuous monitoring, research, and dialogue to address the challenges posed by such advanced weaponry. This document aims to contribute to the understanding and informed discussion on the use and regulation of cluster munitions in contemporary warfare.

APPENDIX 1 – The United States’ Decision to Transfer Cluster Munitions to Ukraine

On March 12, the United States government announced its decision to transfer additional cluster munitions to Ukraine, a move that has sparked significant controversy. This decision runs contrary to the norms established by the international treaty that prohibits the use of these weapons. The context of this transfer is critical to understanding its implications. It comes amid delays by the US Congress in approving military assistance to Ukraine, Ukraine’s shortage of artillery projectiles, and escalating attacks by Russian forces across the country.

The Humanitarian Concerns and Historical Lessons

The history of cluster munitions use by the United States in Afghanistan, Iraq, Laos, and other countries has shown considerable civilian harm. For instance, Laos, the most bombed country in the world per capita, remains heavily contaminated by unexploded ordnance, including cluster munitions, decades after the US dropped them. An estimated 80 million submunitions still pose a danger, especially to children, and fewer than 10 percent of affected areas have been cleared.

Current Use in Ukraine

Cluster munitions have caused significant civilian harm since the beginning of Russia’s full-scale invasion of Ukraine in February 2022. Russia’s armed forces have repeatedly used these weapons, causing hundreds of civilian deaths and injuries. A notable instance was a Russian attack on a train station in Kramatorsk on April 8, 2022, where a ballistic missile carrying a cluster munition warhead killed at least 58 civilians and injured 100 others.

The Ukrainian armed forces have also used cluster munitions to defend against Russia’s invasion, resulting in civilian harm. Investigations by the United Nations and Human Rights Watch found that Ukrainian forces used cluster munitions in and around Izium city in the Kharkiv region during 2022 when the city was controlled by Russian forces. While Ukraine denied these reports, by early 2023, Ukrainian officials began publicly requesting cluster munitions for use in the conflict.

The US Transfers to Ukraine

In response, the US transferred cluster munitions delivered by 155mm artillery projectiles to Ukraine in July and September. In October, the US transferred cluster munitions delivered by ballistic missiles (Army Tactical Missile Systems or ATACMS) with a 100-mile range, each containing 950 M74 antipersonnel/anti-materiel submunitions. The last use of ATACMS containing M74 submunitions by the US was in 2003 in Iraq, where unexploded M74 submunitions littered farmland.

The United States stockpiles 155mm M864 artillery projectiles (each containing 72 dual-purpose improved conventional munition (DPICM) submunitions) and M483A1 projectiles (each containing 88 DPICM submunitions). The M42 and M46 DPICM submunitions, about the size of a D-cell battery, kill and maim indiscriminately.

Humanitarian Consequences and Opposition

The short-term military advantages of using cluster munitions are far outweighed by their devastating and long-term humanitarian consequences. In objecting to the US cluster munition transfers, the foreign minister of Laos warned that these “heinous weapons” continue to pose “serious threats to the lives and livelihood of our people” decades after the conflict.

According to the Cluster Munition Monitor, in 2022, children accounted for 71 percent of all casualties from cluster munition remnants where the age was recorded. DPICM submunitions are particularly attractive to children because they resemble a small bell with a loop of nylon ribbon at the end.

The US Policy and International Reactions

Despite the known dangers, the Biden administration has not provided details on the specific types, quantities, and dud rates of the cluster munitions transferred to Ukraine or on the transit points and anticipated end date for the transfers. President Joe Biden has bypassed US arms export rules in place since 2008, which prevented the US from exporting cluster munitions that resulted in more than one percent unexploded ordnance across the range of intended operational environments.

On July 7, 2023, Biden signed a presidential “determination” allowing the Pentagon to provide Ukraine with an unspecified quantity of US cluster munitions with a failure rate exceeding one percent. US Department of Defense officials claim the DPICM submunitions “have a dud rate less than 2.35 percent” but say that the testing data behind this number is “classified.”

Transparency and Accountability

Transparency is crucial for accountability and democracy. In practical terms, clearance operators need detailed information to understand the scale and extent of the threat from explosive remnants, especially unexploded submunitions. The cluster munitions that the US is sending to Ukraine are more than 20 years old, scatter over a wide area, and have a notoriously high dud rate, leaving a costly and deadly legacy of contamination.

The M42 and M46 DPICM submunitions fail at a rate of at least 14 percent, while the M74 submunitions delivered by ballistic missile (ATACMS) are understood to have a failure rate of 5 to 10 percent, if not higher. Environmental factors in parts of Ukraine such as dense vegetation, high winds, and soil density, and delivery factors such as high wind will most likely contribute to producing an even higher operational dud rate.

International Legal and Humanitarian Implications

Previous recipients of US cluster munitions had to agree that the munitions “will only be used against clearly defined military targets and will not be used where civilians are known to be present or in areas normally inhabited by civilians.” This time, the US says it has a “classified” agreement with Ukraine regarding how the cluster munitions will be used. According to a senior US defense official, “the Ukrainian government has offered assurances in writing on the responsible use of [cluster munitions], including that they will not use the rounds in civilian-populated urban environments and that they will record where they use these rounds, which will simplify later demining efforts.” These assurances follow five “key principles” for Ukrainian use of cluster munitions that Ukraine’s then-Defense Minister Oleksii Reznikov outlined on X (formerly Twitter) last July.

The Convention on Cluster Munitions

The ongoing transfers and use of cluster munitions raise concerns for states parties to the 2008 Convention on Cluster Munitions. In September, they collectively “condemned any use of cluster munitions by any actor” and expressed “grave concern at the significant increase in civilian casualties and the humanitarian impact resulting from the repeated and well-documented use of cluster munitions,” particularly in respect to “the use of cluster munitions in Ukraine.”

The US did not participate in negotiating the Convention on Cluster Munitions, but key allies did, and the convention’s states parties include 25 of the 32 NATO member states. The convention explicitly requires its states parties not to assist with any activities banned by the convention, a strict standard that has impacted non-signatories such as the US.

Evolution of US Policy on Cluster Munitions

After the convention was adopted in Dublin on May 30, 2008, the US had appeared to be gradually moving away from cluster munitions as it developed alternative weapons and means of fighting in wars. While the US says it sees military utility in cluster munitions, it has not used them since its 2003 invasion of Iraq, with the exception of a single attack in Yemen in 2009. The US last produced cluster munitions in 2016.

Current US Stockpiles and Transfers

The United States still possesses a stockpile of cluster munitions, which it is now drawing on to supply Ukraine. The US transfers stand in stark contrast to the actions of countries that have prohibited cluster munitions. For example, last September, Bulgaria, Slovakia, and South Africa formally announced the completion of the destruction of their stockpiled cluster munitions. In December, Peru, the last state party with stockpiles of cluster munitions, completely destroyed them, a significant milestone for the convention.

Humanitarian Costs and Future Challenges

Governments pushing to rebuild Ukraine already face a high cost to clear and destroy landmines and unexploded ordnance, including cluster munition remnants used by Russia. The use of such weapons by Ukraine and the US cluster munition transfers will only increase this cost.

The US Cluster Munition Coalition recommends that President Biden should immediately halt the transfer of cluster munitions given the significant humanitarian, human rights, and political risks involved. The US should take steps to accede to the Convention on Cluster Munitions without delay.

In conclusion, the decision to transfer cluster munitions to Ukraine is fraught with significant ethical, humanitarian, and political implications. The historical and ongoing use of these weapons underscores the urgent need for a global commitment to eliminate them. The international community must hold states accountable for the use of such weapons and work collectively to mitigate the long-term consequences of their deployment. The future of global peace and security depends on the decisions made today regarding the use of indiscriminate and inhumane weapons like cluster munitions.

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