S-400 vs Project Kusha: Range, Capabilities and India’s Air Defence Strategy

If there is something that the ongoing US-Israeli war with Iran has demonstrated that it is how drones, cruise missiles and ballistic missiles can threaten even countries equipped with advanced air-defence systems. By 15 October 2026, a Reuters investigation had identified at least 135 Iranian or Iran-linked drone and missile attacks on 84 critical infrastructure sites across the Gulf, including energy facilities, ports and airports. Although air-defence systems have intercepted thousands of incoming threats, repeated attacks have still caused significant damage.

The experience highlights the importance of detection, coordinated command and control, sufficient stocks of interceptors, and the ability to engage threats across different ranges.

India faced a similar challenge during Operation Sindoor in May 2025, when Pakistan launched drones and missiles against Indian military and other targets. Our integrated counter-drone grid and air-defence systems neutralised the attacks, while the indigenous Akash system and the Russian S-400 were among the systems most credited with shielding the country’s critical assets.

This brings us to two important programmes: the Russian S-400, which is already in Indian service, and Project Kusha, India’s effort to develop an indigenous long-range surface-to-air missile system. The comparison is not simply about missile range but also about operational maturity, sensor networks, supply chains and India’s ability to sustain an air-defence campaign. Before we jump in directly for comparison, here is a little overview of both systems, which pretty much tells you everything you need to know about these systems, after which you can just glance through the comparison table below.

India’s S-400 deal with Russia

In 2018, India signed a contract with Russia for five S-400 Triumf long-range surface-to-air missile systems. The deal was valued at approximately US$5.43 billion, or around ₹40,000 crore at the time. The original delivery schedule called for deliveries to begin in 2020 and end by April 2023, but supplies were delayed, including due to disruptions caused by Russia’s war against Ukraine.

As of September 2026, four of the five original systems are operational, with the fifth expected by November 2026.

In March 2026, the Defence Acquisition Council cleared a proposal to acquire five additional S-400 systems. By August, Russia had submitted a detailed proposal estimated at more than ₹50,000 crore, which was still being processed, according to media reports.

The purchase exposed India to the risk of US sanctions under the Countering America’s Adversaries Through Sanctions Act (CAATSA), which targets certain significant transactions with Russia’s defence sector. The US warned countries about such purchases, and India proceeded despite the pressure, while Turkey was expelled from the F-35 programme for purchasing the same system. This decision signifies how critical the S-400 is for our air defence.

What does one S-400 system comprise?

The S-400 is not a collection of launchers operating independently. It is a networked weapon system built around surveillance radars, engagement radars, command posts, missile launchers and supporting vehicles.

A typical S-400 battery includes – Refer to graphic image for better visual understanding

A search radar develops a picture of the airspace; command systems evaluate and distribute that information; an engagement radar and launcher then work together to attack a selected target. The system can also operate alongside wider air-defence sensors and command networks.

Missile types and engagement range

One of the S-400’s advantages is its ability to use different interceptor missiles.

• 9M96E: Engagement range of approximately 40-60 km.
• 9M96E2: Engagement range of approximately 120 km.
• 48N6 variants: Approximately 200–250 km, depending on the variant.
• 40N6E: Maximum reported engagement range of approximately 380–400 km.

Also, these are published or reported maximum ranges, not guarantees of a successful engagement at those distances against every target. Radar horizon, terrain, target characteristics, electronic warfare and the geometry of an engagement all affect at what range a system can execute an interception.

The S-400 during Operation Sindoor

During the operation the system demonstrated why it was strategic asset.

In August 2025, Chief of the Air Staff Air Chief Marshal A. P. Singh said India had brought down at least five Pakistani fighter aircraft and one large aircraft, which could have been an airborne early-warning or electronic-intelligence platform. He said the large aircraft had been hit at a distance of about 300 km and described the S-400 as a game changer because its range helped keep Pakistani aircraft away.

The broader point is that long-range air defence can affect an opponent’s behaviour even when it does not fire. The possibility of being tracked and engaged at long range can constrain an adversary’s ability to position aircraft for surveillance, electronic warfare or weapon launches.

However, maintaining such capability comes with a significant sustainment requirement. The missiles are imported, replenishment depends on supply arrangements, and an extended conflict could consume stocks much faster than peacetime procurement plans anticipate.

This became visible after Operation Sindoor. In February 2026, the Defence Acquisition Council accorded Acceptance of Necessity (AoN) for the reported purchase of 288 additional S-400 missiles at an estimated cost of ₹10,000 crore. The package was reported to include 120 short-range and 168 long-range missiles(Although not public).

That requirement is one reason Project Kusha matters to India beyond the question of maximum range.

Project Kusha: India’s indigenous long-range air-defence system

Project Kusha is India’s effort to develop a long-range surface-to-air missile system capable of engaging aircraft, unmanned aerial vehicles, missiles and large airborne platforms at extended ranges. It has also been referred to as XR-SAM or Long-Range Surface-to-Air Missile (LR-SAM).

The Cabinet Committee on Security cleared the development programme in 2022, with an outlay reported at approximately ₹21,700 crore. In September 2023, the Defence Acquisition Council reportedly granted AoN for multiple squadrons for the Indian Air Force, the lead service for the programme. The Navy is also expected to have a future requirement for a shipborne variant, although that should not be confused with the current land-based system.

A major milestone followed on 23 July 2026, when DRDO successfully conducted Kusha’s maiden flight test from the APJ Abdul Kalam Island test facility off the Odisha coast. The test involved an electronic target simulating a high-speed, high-altitude aerial threat, which the missile successfully intercepted. This showed that the programme has moved into flight testing.

What will a Kusha firing unit comprise?

The system’s missiles, radars and command-and-control centre had been developed by DRDO laboratories and Indian industry partners. This indicates a dedicated system architecture rather than a mere missile programme relying entirely on various existing radar suites operational with armed forces.

At a functional level, a Kusha unit will have the following elements:

There is not yet more information as to the number of radars, launchers or reload vehicles in a Kusha squadron, nor information about the precise radar models and their performance.

Kusha should nevertheless be expected to operate within our wider air-defence network. But there is not enough public evidence to state that existing radars will replace Kusha’s own radar suite, or to describe exactly how its sensors will connect to the IAF’s Integrated Air Command and Control System (IACCS).

The M1, M2 and M3 interceptor variants

Reporting published around the July 2026 test describes Kusha as having three interceptor variants with progressively greater reach:

One of the most important objective of Kusha’s development also involves development of wider domestic industrial base. The Defence Research and Development Laboratory as the lead for interceptor development, Research Centre Imarat as responsible for seekers, Bharat Electronics Limited as a principal production partner, and Bharat Dynamics Limited as involved in missile manufacture.

The remaining challenge is to turn the successful first test into a mature system. That requires further testing across different engagement conditions, validation of the complete radar-to-command-to-missile chain, reliability trials, production capacity and eventual induction.

S-400 vs Project Kusha: The actual comparison

The most important distinction is that the S-400 is an operational system with combat experience, whereas Kusha is still under development.

Well we may conclude that Kusha could match the S-400 because both are associated with engagement ranges of around 400 km. That would be premature.

First, maximum range depends on the interceptor and target conditions. A large aircraft at high altitude is not equivalent to a low-flying cruise missile or a small drone. Second, the ability to detect a target, maintain an accurate track and guide an interceptor is as important as the missile’s advertised reach. Finally, operational performance depends on how quickly a system can process multiple threats, withstand electronic countermeasures, reload and continue fighting.

The S-400 has an established architecture and operational history. Kusha must demonstrate those qualities through a larger programme of testing and, eventually, service experience. Its reported M3 range is promising.

Why Kusha matters for India

The graphic above illustrates how India’s integrated air-defence architecture could look once Project Kusha enters service, with multiple systems providing layered protection from short-range threats to long-range aerial targets. India’s ballistic missile defence (BMD) programme, however, is a separate subject for another day.

Operation Sindoor highlighted an uncomfortable reality for any country preparing for a prolonged conflict: even a capable air-defence system can become constrained by interceptor stocks. India’s reported AoN(acceptance of necessity, in case you guys forgot) for 288 additional S-400 missiles, estimated at ₹10,000 crore, show the scale of the replenishment requirement.

An operational Kusha would give India a domestic route to developing and manufacturing long-range interceptors. That could reduce dependence on Russian production schedules and foreign approvals, while giving DRDO and Indian industry greater control over future modifications as well as domestic production can improve control over supply.

Thus, the S-400 and Project Kusha address a similar broad requirement: long-range air defence against sophisticated airborne threats. Kusha is India’s attempt to build a comparable capability domestically. Until that happens, the S-400 remains an important operational asset, and Kusha remains a strategically significant programme for the future.