ST-35 Silent Thunder Loitering Munition

ST-35 Silent Thunder is a new loitering munition being developed by Athlon Avia, a Ukraine-based producer of unmanned aircraft systems.

Project Type

Loitering munition


Athlon Avia

Maximum Take-Off Weight



60 minutes


ST-35 Silent Thunder is a new loitering munition being developed by Athlon Avia, a Ukraine-based producer of unmanned aircraft systems.

The precision-guided weapon system will be able to destroy the enemy targets with minimal risk to people and infrastructure around the targets.

It will be used to target radar stations, command posts, as well as command and control platforms. It will have the capability of defeating particularly important and valuable targets in closed positions.

Athlon Avia unveiled the new model of single-use drone in October 2019. The loitering munition is intended for use by the Armed Forces of Ukraine.

The company concluded the initial series of guided flight trials in March 2020. The loitering munition was evaluated at different modes during the next stage of testing conducted in April 2020. The next phase of development involves the testing of warhead in late-2020.

ST-35 Silent Thunder design and features

ST-35 Silent Thunder features a multi-copter design integrating a transponder and a single-use munition. The loitering munition incorporates X-layout biplane scheme which ensures accuracy during horizontal flight and vertical trajectory for precision target attack. The probability of loitering munition hitting the target is approximately 95%, while circular deviation is up to 3m.

The weapon system will be complemented by a ground control station, optical payload, warhead, multi-rotor, dropping module, relay module, antenna complex, as well as spare parts, tools and equipment.

The loitering munition will be guided semi-automatically with the use of television or infrared (IR) guidance heads which can be swapped based on visibility and weather conditions.

The fast moving target ensures quiet and unnoticeable operation. It can be operated in silent mode and at an altitude of 1,200m, making it a difficult target to detect.

The length and width of the weapon will be 300mm and 90mm respectively, while its take-off weight will be 9.5kg.

The ST-35 single-use drone will employ a human operator for locating targets and will be able to perform autonomous flight after launch. It can assess weather conditions, approach the aiming point, and dive at the target while operating autonomously.

Deployment and launch of ST-35 Silent Thunder

The fuselage of ST-35 loitering munition will be fixed after the deployment of the launch platform. The payload module and the optical section will be connected to the fuselage, while dropping module, central section and multi-rotor assembly will be hinged to launch the loitering munition.

The pre-flight systems will be checked and the aerial system will be vertically launched to an altitude of 400 to 600m, where the loitering munition will be undocked from the multi-rotor platform to ensure horizontal flight towards the target.

The multi-rotor platform will return to the launch pad after undocking. It will be attached with the relay module with antennas and will be flown to an altitude of 1,000m to support the relay of signals between the loitering munition and operator.

The aerial system will conduct pre-intelligence procedures which will enable the operator to detect the target. Target destruction will be confirmed upon visual confirmation from the operator.


ST-35 Silent Thunder will be armed with fuel-air explosive (FAE) warhead weighing up to 3.5kg. It will also have the capacity to be fitted with high-explosive anti-tank (HEAT) and high-explosive fragmentation (HEF) warheads.

Athlon Avia also intends to develop a shaped charge warhead to avoid collateral damage during high-risk missions.

ST-35 Silent Thunder performance

The ST-35 Silent Thunder loitering weapon will have a cruise speed of 120km/h. It will have an operational range of approximately 40km.

The loitering munition can be deployed in 15 to 20 minutes. It can remain airborne for up to 60 minutes.

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