Modernized Osa SAM for Ukraine? Ad Hoc Gap-Filler Needed

Fot. Ştefan Ciocan/CC-BY-SA-3.0
Fot. Ştefan Ciocan/CC-BY-SA-3.0

Ukraine, fighting the Russian aggressor, would be tackling the increasingly more burning matter, namely the depletion of the national SAM stockpile. The Western capacity to replenish that stockpile is fairly limited, as no post-Soviet systems are available in the NATO countries. The modernization concept for the Osa SAM, developed by the Polish defence industry years ago may be a viable option here.


The Ukrainian air defence assets play a very important role in pushing back the Russian aggressor. They protect both the infrastructure, as well as the forces fighting along the frontline. The effectiveness would depend on the tactics adopted by Russian aviation - and as shows - it was forced to use a certain set of precautions.


The airstrikes deep in the Ukrainian territory are done in a stand-off fashion, with the use of long-range munitions, such as cruise missiles, or even SAMs used in a surface-to-surface role. Meanwhile, the air platforms (helicopters and attack aircraft) usually employ the spray and pray tactics. This set of tactics involves a low-level approach to the target and the launching of an unguided rocket salvo using a ballistic trajectory. Then the aircraft rapidly leaves the endangered area. This translates into limited accuracy.

The Russian Air Force does not enjoy a whole lot of operational freedom over Ukraine - and this is the best proof of the fact that the Ukrainian air defences remain highly lethal. One may risk stating that this lethality has come by as a surprise for many experts. In the future, this would require more support from the West. The stockpile of the post-Soviet missiles would be depleted soon.


At the same time, the NATO member states with a limited inventory of air defence systems, apart from VSHORAD assets (a result of the recent cuts), need to procure brand new systems to fill in the gaps. And newly manufactured systems are expensive, while the production processes do take time. Even though the first decisions have already been made, with the United States procuring 2 NASAMS batteries, and Germany a single IRIS-T battery, the requirements are ten-fold higher. It is worth giving some thought to the process needed to be pursued, to reinforce the air defences.

The Ukrainian air defence assets include Russian/Soviet systems, such as medium-range S-300PS/PT systems, some S-300V systems, Buk-M1 medium/short-range systems, and the Osa SHORAD solution. A minor quantity of Tor and Neva systems is also available. Kyiv has received most of the support in the VSHORAD domain (Stinger, Starstreak, Piorun systems). It also uses its own Tunguska and Strela-10M systems, alongside the Igla MANPADS. The post-Soviet self-propelled assets are now accompanied by the German Gepards and British Starstreak HVMs - in minor quantities.

Air War in Ukraine Evolves into a New Phase

Among the systems operated by Ukraine, the SHORAD Osa system stands out, used to defend mobile land forces units. Osa is a SHORAD SAM that can neutralize targets at a distance of up to 10 to 13 kilometers, flying at an altitude of 5,000 meters. From the point of view of support for Ukraine, Osa distinguishes itself by the fact that it is operated by NATO members, such as Poland, Romania, and Greece. Contrary to other systems that were not being exported outside the Warsaw Pact during the Soviet era (Buk, Tunguska), Osa is well known to the NATO defence industry, and also to the Polish defence industry.

The Polish Osa systems have undergone an in-depth upgrade finalized a few years back. They are currently still being modified. Several analog subsystems underwent digitalization, and radars have been modernized and complemented with optoelectronics featuring thermal imagers and video trackers. The C2 suite has been upgraded as well. The system is referred to as Osa-P. Nonetheless, the missiles have been unchanged, but they are the most limiting factor for the capability of the Osa system. The guidance system that requires data for the firing solution to be processed extends the reaction time. "Encyklopedia Najnowszej Broni Palnej" (Encyclopedia of the Latest Weapons) published by Bellona in 2001-2002, states that the reaction time is as long as 15 seconds (for a standard Osa system).

Furthermore, the missile needs to receive radio commands throughout the engagement. The Osa system cannot engage other targets, until hitting the first threat that also needs to be tracked by the launcher's radar. All of the above diminishes the lethality of that system on the modern, dynamic battlefield.

Replacement of the missile could solve some of those problems. The Polish defence industry has been involved in a conceptual study regarding that matter. A few years ago Osa, with mock-ups of new missiles, has been presented during the MSPO event in Kielce. Osa was showcased with the German IRIS-T short-range missiles that can also be used in a surface-to-air setting. The Swedish Army certainly utilizes this approach. Norwegian Armed Forces would follow in their footsteps, for two of their SAM systems.

The introduction of IRIS-T or similar IR-guided missiles for Osa (with a range of at least dozen kilometers, capable of reaching altitudes of up to 6-8 kilometers when ground-launched) would decisively improve the Osa's combat capabilities. Osas could act against a higher number of targets in a short time. There would be no necessity to guide the missile during the engagement which, in turn, would improve the flexibility and safety of the SAM operators.

Most probably the reaction time would also be shortened - this has a relevant value in the dynamic air defence landscape. Not to mention the fact that a major stockpile of IRIS-T-class missiles for instance is available in the West. A steady supply of those could be easily provided. So far missiles with a range not exceeding 7 kilometers have been provided by the West. Using short-range missiles (actually, modified AAMs) could make it possible to neutralize threats at greater distances and altitudes.

IRIS-T/Osa concept.
IRIS-T/Osa concept.

US-made AIM-9 Sidewinder could be viewed as another viable solution with a similar set of capabilities. Noteworthy, both IRIS-T, as well as the AIM-9X can be used on the NASAMS systems, expected to be supplied to Ukraine as a part of the military aid package.

The PGZ Group has made the following statement, regarding the envelope expansion programme for the Osa system: WZU S.A. sees a possibility of equipping the OSA SAM with a new effector which would increase the platform's capability, apart from the gains achieved as a result of the implemented upgrade. The potential new set of capabilities includes a capacity to guide new generation missiles, with the use of an optronic sensor. The new optronic sensor allows for use of a "fire-and-forget" missile and an increase of the SAM system's firepower. (...) Preliminary talks with Diehl BGT - the manufacturer of the IRIS-T SL missile - have already been underway. During the talks, data on tactical and technical specs of the missile, and tests involving a ground-based launcher has been obtained. Based on the collected information we positively rate the option to use this weapons system on the Osa platform. A complete interface for mechanical integration on the OSA SAM system has been developed, along with a general concept of the electrical interface. From the technical standpoint, there are no obstacles to the continuation of the development of the final solution.

The conceptual work regarding the introduction of a new effector for the Osa system, the AIM-9X missile was being considered - as it is also used by the Polish F-16 jets. As the PGZ Group assures, no talks are currently underway, regarding the integration of new missiles.

Integration of a new anti-aircraft missile on the Osa system would take time. First, one should finalize and test the prototype, and then modify the series-manufactured systems which would require them to be transported to the location where the work would take place, with procurement of relevant components and integration also being required steps along the way.

Throughout the analytical portion of the effort, an assessment of the feasibility of backward compatibility with legacy missiles would also be needed. If a requirement as such emerges, the system would retain a greater degree of flexibility, as two different missile types, with two different guidance units, could be launched. If not - the system would be easier to handle, actually becoming an entirely different air defence asset but without a capacity to utilize the existing stock of Osa missiles. This would also have an impact on the operator training, and the number of crewmembers.

One should remember that the conflict in Ukraine would continue, and Kyiv's needs in the air defence department would only grow. The western stockpile of similar air defence systems, manufactured by the western industry, remains fairly limited. Contrary to SHORAD systems - these can be shared with Ukraine without any risk of endangering their inventory. The pressure imposed by time also suggests that integration shall involve an existing missile, not one that would be brand new (such as the effector developed within the framework of the SONA programme).

At least a few possible variants of Osa upgrade (involving the integration of a new missile) exist, that could reinforce the Ukrainian air defences:

  1. Modernization of Ukrainian systems, within the framework of overhauls and repairs performed in the NATO member states. Here, some of those systems would be temporarily disabled. However, overhauls as such are required throughout the lifecycle anyway.
  • Modernization of systems operated by NATO member states - Poland, Greece, Romania. In this scenario, the aforesaid nations could only use new missiles exclusively, while Ukraine could potentially replenish its stock.
  • Fusion of two variants above: modernization of all Osa systems operated by NATO member states, with some of them being transferred to Ukraine which would be then followed by a gradual upgrade of the Ukrainian Osa systems. In this scenario, Ukraine would have a growing inventory of modernized systems, while the NATO member states would partially compensate for the loss of their systems, through a major improvement of the potential of the systems that would remain in service.
  • Modernization of the surplus systems coming from the states that have already decommissioned their Osa stock. A few years back Jordan was offering its systems for sale. Some of them were procured by Armenia, but some stock may also be available among other nations - possibly in Bulgaria.

The potential delivery of Osa systems to Ukraine, with those systems being able to launch new missiles could substantially reinforce the Ukrainian air defence potential. This would require a myriad of concepts to be analyzed, and industrial effort to be launched.

One could say that Kyiv shall only receive brand new equipment, but the manufacturing potential has its limits, while the needs are huge. In the longer run, dozens of batteries and hundreds of different air defence assets (e.g. launchers) would need to be replaced. And we are speaking of a situation in which the NATO member states are facing a prospect of a lengthy recovery in the air defence domain, after many years of cuts. The delivery of air-to-air missiles that would be tailored to the SAM role (such as Sidewinder or IRIS-T) would be much easier. The United States and the European nations do have a certain stockpile of those. This could happen on the condition that Ukraine also receives the launchers.

One of the proposed modifications of the Avenger system, with Sidewinder missiles.
One of the proposed modifications of the Avenger system, with Sidewinder missiles.
Photo. Boeing Defense/Twitter

One could consider whether the modernized Osa system could be used in that role. At least two effector options are on the table (IRIS-T/Sidewinder families). If the Western nations decide to provide Ukraine with a major quantity of IRIS-T missiles they could receive a certain number of Sidewinders (temporarily), to replace them, coming from the US stock. Most of the aircraft using the IRIS-T can also launch the Sidewinders. This would be a perfect scenario to use the Lend & Lease regulations. Let us add that the recent information on the use of the HARM missiles by the Ukrainian Air Force, being launched from Russian jets (if confirmed) may prove that integration of post-Soviet systems and Russian armament is not necessarily a challenging and lengthy process as it would seem at the first glance, especially during the wartime, when there is no need to carry out lengthy certification processes.

Other solutions shall be taken into the account as well. For instance, the US industry has been offering to integrate the Sidewinder missiles on the Avenger system, while some of the US Congressmen called for a transfer of the Avenger systems to Ukraine. A system as such would be reminiscent of the Chapparal systems dating back to the 1990s. The integration of IR-guided AAMs on SAM systems using optronic targeting suites shall be simple and feasible. The question that remains open pertains to the base platform and delivery schedules - both if the Osa modernization path is chosen, or when new launchers using the existing missile stockpile are developed.

One thing is certain. The Ukrainian air defence assets, including ones protecting the land forces, need to undergo a reinforcement, through an upgrade or delivery of new systems (or new missiles, if such effectors are integrated on the Osa SAM). The post-Soviet systems have a limited lifetime, while the end of the war (and the end of the Russian threat, even in the event of a ceasefire) is nowhere to be spotted.