Russia’s New UMPB Glide Bomb May Be Advancing Toward Widespread Deployment

In February 2022, Russia invaded Ukraine with an air force that was heavily reliant on the use of unguided aerial bombs and unguided aerial rockets. Not only were the aerial attacks undertaken with such weapons inaccurate, but Russia’s air force also lacked the capacity to suppress Ukraine’s air defences, particularly the mobile Soviet air defence systems with which the Russian military is so intimately familiar. Attrition rates were unsustainably high and, after several weeks of largely ineffectual and extremely costly aerial bombing efforts, the Russian Air Force reverted to a supporting role when it came to air-to-ground missions. Over the next twelve months or so, the Russian Air Force’s large fleet of combat aircraft was mostly limited to highly inaccurate and therefore highly ineffectual attacks involving the use of lofted unguided bombs and lofted unguided aerial rockets toward Ukrainian positions along the frontlines. Russia’s military industry was, however, belatedly working on correctives to these glaring and heavily taxing shortcomings.

In January 2023, reports emerged of the development of a guidance and wing assembly for Russia’s Soviet-pattern unguided aerial bombs, with evidence of increasingly widespread use unfolding over the spring of 2023. By the autumn of 2023, Russia’s UMPK (Unified Gliding and Correction Module) guidance and wing assembly became a regular feature of the Russia-Ukraine War. The UMPK combines an inertial navigation system (INS) and global navigation satellite system (GNSS) guidance module with a folding wing that respectively improve the accuracy and the glide ratio of the unguided bomb to which the UMPK is attached. Alongside a range of other improvements in Russia’s combat capabilities, the UMPK guidance and wing assembly contributed to the success of Russian offensives in the 2023-2024 winter fighting season including the capture of the Ukrainian town of Avdiivka. In March 2024, Ukrainian sources reported that Russia was starting to employ, possibly in combat trials, a new guided glide bomb design, the UMPB (Universal Interspecific Gliding Munition), with a reported maximum range of over fifty kilometers. As of late May 2024, which is to say around twenty-seven months into the Russia-Ukraine War, there are indications that the UMPB may be entering frontline service as Russia’s first purpose-built guided glide bomb.

Patching A Glaring Capability Gap

Whereas the United States and leading militaries worldwide heavily invested in guided aerial munitions of various types following the Gulf War, Russia was in no position to fund the development or procurement of such systems following the dissolution of the Soviet Union. While Russia’s military industry developed several standoff munitions for combat aircraft since the late 1990s, these tended to be more expensive powered standoff munition designs that could only be procured in small numbers. Beyond resource limitations, Russia, which was already a laggard in the electronics industry at the time the Soviet Union dissolved, was highly dependent on the importation of foreign electronic components. As a result, in 2022, Russia’s military industry had to largely start from scratch to develop an affordable guided bomb that could be built and employed in very large numbers at the earliest possible opportunity. Having been hastily put together to meet pressing wartime needs in the absence of “on-the-shelf” designs ready for production, the UMPK is unsurprisingly a relatively crude design. In large part, this is a reflection of the differences between Soviet and American approaches to aerial bomb design and, as such, the burdensome legacy imposed by the Soviet era on the Russian military when it comes to the adoption of guided aerial weapons.

The American Mark 80 series of (unguided) general-purpose aerial bombs, which are increasingly ubiquitous worldwide, have separate nose and tail sections to which guidance sections can be added. As a result, the early Cold War origin Mark 80 series has been well suited to incorporating various guidance kits as these become available. This includes the American Paveway series laser guidance nose and tail kit and the American Joint Direct Attack Munition (JDAM) strake and tail kit, which incorporates both INS and a GNSS receiver. Soviet-Russian aerial bombs, in contrast, are welded monoliths in terms of construction and cannot as readily be fitted with guidance kits. The UMPK is essentially an independent guidance system and folding wing assembly that is attached to an unguided Soviet-pattern aerial bomb. It is therefore a much cruder system than its foreign analogues, which mostly use the American Mark 80 series, and should therefore be viewed as an expedient wartime solution to a pressing operational requirement rather than the best design that Russia’s military industry could necessarily come up with.

Notwithstanding its many limitations and the reported unreliability of early production versions, the UMPK has, as of May 2024, seen extensive use for over a year and, in later more refined iterations, is reportedly a mostly reliable and mostly effective system that not only fulfills its intended purpose but, most importantly, plugs a critical gap in Russian military capabilities. While initially employed with 500-kilogram (~1100 lb.) FAB series high explosive-fragmentation bombs, the UMPK has since also been deployed with 500-kilogram RBK series cluster bombs and 500-kilogram ODAB series thermobaric bombs. Reports indicate that Russia has also developed a version of the UMPK that is compatible with the 250-kilogram (~550 lb.) OFAB series high explosive-enhanced fragmentation bombs, which have a thicker casing for enhanced fragmentation effects, as well as versions compatible with much larger 1500-kilogram (~3300 lb.) FAB series high explosive-fragmentation and ODAB series high explosive bombs. Russia is reportedly also developing a UMPK guidance and wing assembly compatible with the extremely large and heavy 3000-kilogram (~6600 lb.) FAB series high explosive-fragmentation bomb.

Figure 1. A further evolution of the UMPK on display in January 2024. Source: Russian state media.

While the UMPK appears to mostly work as advertised, it has limitations and Russia’s military pursued a more effective and enduring solution. Given the legacy of Soviet bomb design, Russia stood to benefit from a new standalone unitary guided glide bomb design that incorporated the guidance system and deployable wing into a single new airframe. This would result in a lighter and more compact design that could be more readily employed with standard Soviet-Russian aircraft pylons without overloading the weap to which these are attached, a dynamic that is reportedly the primary cause of repeated cases of the inadvertent premature release of UMPK-equipped aerial bombs over Russian and Russian-controlled territory, including the Russian city of Belgorod. A new unitary guided glide bomb design can also be aerodynamically optimized and therefore offer a superior glide performance, a key consideration given the need to employ standoff attacks to evade Ukrainian air defences and thereby lower attrition rates.

Having been hurriedly developed and put into service in pressing wartime conditions, the UMPK is also limited in other respects. Reports indicate that the target location data must be entered into UMPK guidance systems on the ground and that the UMPK cannot be fed new target location data by the onboard weapons system officer while in flight. This makes the UMPK unsuited to attacking time-sensitive targets and Russian aircraft equipped with the UMPK are, in effect, employed in a suboptimal and inflexible manner analogous to pre-planned artillery fire. A new standalone unitary guided glide bomb design integrated into the combat management system of the host aircraft can be employed in a far more effective manner. By the spring of 2024, reports indicated that Russia was starting to employ just such unitary guided glide bomb design, the new UMPB.

A Russian GBU-39 (Small Diameter Bomb)?

Figure 2. Four UMPB bombs released by a Russian Su-34 strike aircraft in May 2024. Source: AviaHub (Telegram)

When the UMPB was first unveiled in March 2024, many observers focused on the superficial similarities of this smaller guided glide bomb design with the American GBU-39 Small Diameter Bomb (SDB), which is also a unitary design incorporating an integrated INS+GNSS guidance system as well as a folding wing to extend the glide range of the unpowered bomb. With very limited data on the UMPB being public knowledge as of this writing, one of the areas of uncertainty concerns the extent to which the UMPB is unlike the American GBU-39. Given its reported weight of over 200 kilograms, the UMPB is inherently dissimilar to the much smaller GBU-39, which weighs around 130 kilograms. This major difference in weight has a variety of implications, including the fact that Russian aircraft will not be able to carry multiple UMPB guided glide bombs on a single weapons station in the manner that American combat aircraft can carry up to four of the lighter GBU-39 guided glide bombs on a single high-capacity bomb rack. The difference in weight also suggests that the UMPB is likely to contain a general-purpose bomb as its warhead, at least in the baseline version, and this would also make it dissimilar to the American GBU-39 in multiple respects.

The most widely used American general-purpose aerial bomb, the Mark 82 (which is designated the GBU-38 when equipped with the JDAM INS+GNSS guidance kit), has a nominal weight of around 226 kilograms (500 lb.), of which around 40% is explosive filling. The United States previously employed the smaller Mark 81, which has a nominal weight of around 113 kilograms (250 lb.), of which around 36% is explosive filling (a JDAM INS+GNSS guidance kit was not developed for the Mark 81). The GBU-39, in contrast, weighs around 130 kilograms (285 lb.), of which just 12% is explosive filling. This disproportionate reduction in the explosive filling of the GBU-39 relative to the Mark 82 and Mark 81 is reflective of the GBU-39’s use of a warhead optimized for the penetration of reinforced concrete structures over the combination of blast damage and fragmentation effects for which general purpose bombs are optimized. The GBU-39 is, as such, a niche weapon even though the well-resourced American military tends to employ it against a wider selection of targets because its low weight allows a single aircraft can carry a much larger number of GBU-39s than heavier bombs of the Mark 80 series and because the smaller explosive content aligns with recent American practices toward reducing civilian casualties as well as fratricide in close air support missions (the GBU-39 is also equipped with an airburst fusing mode for use against certain targets).

While little is publicly known about the UMPB’s design and specifications as of this writing in late May 2024, the new Russian guided glide bomb is unlikely to be optimized for penetrating hardened structures in the same manner as the American GBU-39 given the relative paucity of hardened structures along the frontlines in Ukraine and, more importantly, Russia’s dire need for standoff munitions to compensate for a wide range of shortcomings in its military capabilities including the existing UMPK guidance and wing kit. It is therefore likely that the baseline UMPB employs either a high explosive-fragmentation warhead, as with the FAB series of Soviet-Russian aerial bombs, or a high explosive-enhanced fragmentation warhead with a thicker casing, as with the OFAB series of Soviet-Russian aerial bombs. If so, the UMPB would be fundamentally dissimilar to the American GBU-39 despite the superficial similarities. Furthermore, if the UMPB’s design is successful, if production can be scaled up quickly, and if production costs are not unfavorable when compared with the UMPK currently in widespread service, Russia is likely to adapt the UMPB to employ different warheads.

Unlike the United States and countries employing the American Mark 80 family of aerial bombs in both unguided and guided forms, the Soviet Union and, in turn, Russia employ a wide range of unguided aerial bomb types including the RBK series of cluster bombs (the UMPK guidance and wing assembly has notably been used with the RBK-500 cluster bomb), the ODAB series of thermobaric bombs (the UMPK guidance and wing assembly has reportedly been used with the ODAB-500 and ODAB-1500 thermobaric bombs), the ZAB series of incendiary bombs, and the BetAB series of bombs, which are optimized to penetrate hardened targets. There are no American counterparts to some of these bomb types for use with the American Paveway series of laser-guided aerial bomb kits or the JDAM series of INS+GNSS-guided guidance kits. Should versions of the UMPB be developed with multiple warhead options, Russia will belatedly be able to deploy its large and highly diverse arsenal of Soviet aerial bomb designs not only to attack targets with high accuracy but do so in standoff attacks that reduce the exposure of combat aircraft to Ukrainian air defences.

A Ground-Launched UMPB?

While the UMPB is dissimilar to the American GBU-39 in multiple respects, reports suggest that, in time, the UMPB may also be employed in a ground-launched version that makes use of the rocket booster from a heavy artillery rocket system. In American service, the GBU-39 is exclusively employed from fixed-wing aircraft. In the mid-2010s, however, a joint private venture on the part of Boeing and Saab led to research and development efforts to develop the Ground-Launched Small Diameter Bomb (GL-SDB), a system that lacks an American military designation and has only been exported to Ukraine as part of military aid. By employing the rocket booster of the 227 mm diameter artillery rockets launched from the tracked M270 MLRS and wheeled M142 HIMARS artillery rocket systems, the GL-SDB was advertised as being capable of attacking targets up to 150 kilometers away, which amounts to a very significant increase relative to the air-launched GBU-39. Reports suggest that Russia plans to similarly mount the UMPB on the rocket booster used by the larger 300 mm diameter artillery rockets launched from the Soviet-Russian BM-30 Smerch artillery rocket system. Notably, the various rockets employed by the BM-30 are equipped with warheads weighing over 200 kilograms, so it is possible that the BM-30 can employ the UMPB in a ground-launch mode with relatively minor changes to the baseline air-launched version’s design.

If Russia does employ the new UMPB guided glide bomb in such a manner, it will be able to expand its strike capabilities in a manner that is more suited to supporting ground forces with a substitute for high-accuracy close air support, which has hitherto not been widely available, and a ground-launched guided glide bomb will also be more effective in attacking time-sensitive targets. More generally, a ground-launched UMPB guided glide bomb will help relieve pressure on over-taxed Russian combat aircraft currently launching thousands of bombs equipped with the earlier UMPK guidance and wing assemblies per month. As a result, the introduction of the UMPB may, in time, have far greater implications on the Russia-Ukraine War, as well as Russian military capabilities after this war, than the existing UMPK guidance and wing assembly, which is exclusive to fixed-wing combat aircraft.

Many Factors Will Shape The Implications Of The UMPB

As of this writing in late May 2024, much remains uncertain about the UMPB. In principle, this new guided glide bomb can dramatically increase the effectiveness of the Russian Air Force by facilitating the high-accuracy bombing of targets behind the frontline while reducing exposure to Ukraine’s air defences. Whereas the UMPK remains a relatively crude and ad hoc solution intended to fill a glaring gap in Russian military capabilities, the UMPB may constitute a more permanent fix. Over the coming weeks and months, the answers to six key questions will shape the cumulative effects of the introduction of the UMPB on the trajectory of the Russia-Ukraine War.

Which Russian combat aircraft designs will be integrated with and employ the UMPB?

While the new UMPB guided glide bomb appears to have been already integrated onto the Su-34 strike aircraft, it remains to be seen if it will also be integrated with other Russian combat aircraft. The Su-34 may be Russia’s most modern strike aircraft, but Russia has access to a far greater number of the older Su-24 strike aircraft. The Su-24 fleet has been subject to attrition over two years of war and does not benefit from the more advanced, albeit still limited, avionics used on the newer Su-34. The integration of the new UMPB guided glide bomb may give the legacy Su-24 fleet a renewed lease of life and reduce the pressure faced by the heavily taxed Su-34 fleet, which has experienced unsustainable attrition in the absence of readily available standoff munitions and as a result of extensive use in a conflict that has entered its third year.

While the Su-34 and Su-24 fleets have experienced extensive attrition, Russia’s large fleet of Su-25 ground attack aircraft has fared even worse. In the absence of standoff weapons including the UMPK guided and wing assembly, the Su-25 fleet has been reduced to primarily launching unguided aerial rockets on lofted trajectories toward the frontlines in the hopes of evading Ukraine’s air defences. These attacks are extremely inaccurate and, all things considered, a wasteful expenditure of jet fuel and an airframe’s limited flight hours (this can also be said of Ukraine’s employment of the Su-25 in much the same manner). There is therefore a case to be made that the Su-25 fleet stands to benefit most from the potential integration of the UMPB. Although the Su-25’s lower speed and slower acceleration will likely reduce the maximum range of the UMPB, this will likely be greatly offset by the renewed lease of life given to these otherwise largely ineffectual ground attack aircraft.

Although strike and ground attack aircraft are likely to be prioritized for integration with the UMPB, it remains to be seen whether Russia will also integrate this new guided glide bomb with its Su-30 and Su-35 fighter aircraft fleets. In contrast to every other large military, most Russian fighter aircraft are not employed as multirole combat aircraft and instead focus on air-to-air combat. While the Russia-Ukraine War has forced Russia to partially modify this longstanding approach, the forthcoming arrival of American F-16 fighters in Ukrainian service may lead Russia to hold its relatively small fleets of Su-30 and Su-35 fighters in reserve for use in air-to-air combat missions. The integration of the UMPB would nevertheless allow these fighter aircraft to relieve pressure on the strike aircraft fleet when required.

More speculatively, the UMPB could potentially offer Russia’s large but mostly underworked Tu-22M bomber fleet an opportunity to make more meaningful contributions to the war effort. Thus far, the Tu-22M fleet has been used to launch Kh-22 and Kh-32 supersonic (originally anti-ship) cruise missiles, to questionable effect, and arms control treaties proscribe the use of Tu-22M bomber aircraft with subsonic land-attack cruise missiles (which are launched from Tu-95 and Tu-160 bombers within the constraints of arms control treaties). Should the UMPB be integrated with the Tu-22M, a single bomber could be used to launch perhaps 40 or more of these guided glide bombs. As a supersonic bomber, the Tu-22M is particularly well suited to the employment of guided glide bombs, and the ability to deliver a very large number of guided glide bombs – potentially the equivalent of a half dozen or more Su-34 aircraft – in quick succession may play a key role in facilitating the advance of Russian ground forces against entrenched Ukrainian forces.

As of this writing in late May 2024, the UMPB is only reported to have been integrated with the Su-34 strike aircraft and Russia may or may not employ this new guided glide bomb with other aircraft types. Integration across a single fleet of aircraft, let alone across fleets of aircraft, will likely take many weeks if not several months even if the UMPB is readily available for use and in full-rate production.

How many UMPB guided glide bombs will be carried on each weapons station?

One of the most desirable features of the American GBU-39 guided glide bomb is that up to four of these much smaller and lighter aerial bombs can be attached to a bomb rack that is mounted onto a single weapons station. This allows a single combat aircraft, such as a single-engine American F-16 fighter, to carry multiple GBU-39-equipped bomb racks to target eight aimpoints per sortie and a larger twin-engine American F-15E to carry up to sixteen GBU-39 guided glide bombs and thereby attack up to sixteen aimpoints per sortie. In contrast, the Russian twin-engine Su-34 strike aircraft, which is in the same performance class as the F-15E, can only carry up to six 500-kilogram bombs (analogous to the 1000 lb. American Mark 83) equipped with the older UMPK guided and wing assembly, with one bomb mounted on a given weapons station. Should Russia be able to mount two UMPBs per weapons station, a single Su-34 could attack up to twelve aimpoints per sortie. This difference may appear minute when considering a single aircraft or a small number of sorties, but the effects are far greater when considering the thousands of sorties that Russian strike aircraft undertake every month. Simply stated, should Russia be able to equip each of its aircraft with twice as many of the smaller and lighter UMPB relative to the earlier UMPK (most commonly employed to date with 500-kilogram class bombs), it can use a given number of aircraft to attack twice as many aimpoints or, alternatively, use half as many aircraft to attack the same number of aimpoints and thereby preserve the flight hours of its combat aircraft fleet.

To mount more than one UMPB per weapons station, Russia may require new pylons, and these will have to be integrated across the heterogeneous fleet of the Russian Air Force once developed and produced. As such, the maximum potential effects of the UMPB on the Russia-Ukraine War very much depend on factors related to the host aircraft and it will likely take time for Russia to fully integrate the UMPB across its combat aircraft fleet in a manner that enables a maximal gain in the Russian Air Force's combat capabilities.

Will the UMPB be available with multiple warhead options?

The Soviet approach to aerial bomb design had many limitations in the long run and constituted one of several barriers to entry for Russia’s adoption of guided aerial bombs. The Soviet legacy is, however, far more desirable when it comes to warhead options that allow airstrikes to be tailored to specific types of targets, accuracy permitting. With Russia already employing the older UMPK guidance and wing assembly with both RDK cluster bombs and ODAB thermobaric bombs, Russia may, in time, develop versions of the UMPB equipped with other warhead options. If this happens, then the UMPB will be a very versatile weapon in Russia’s toolkit. If this does not happen, then the UMPB will likely be limited to high explosive-fragmentation or high explosive-enhanced fragmentation warheads that are not optimized for a wide range of target types present in the Russia-Ukraine War. The UMPB may, as such, coexist with the existing UMPK guidance and wing assembly, which has been used with cluster and thermobaric bombs, in Russian service for the foreseeable future.

Will the UMPB be integrated with the 300 mm diameter rocket booster of the BM-30?

Although the UMPB has likely been developed primarily as an aerial bomb, the unveiling of this new Russian weapon was accompanied by rumours that it was also intended for use with the 300 mm rocket booster used with the BM-30 Smerch large caliber artillery rocket system. Over the long run, whether this is the case may have outsize effects on the trajectory of the Russia-Ukraine War. While the older UMPK and the newer UMPB increase the capabilities of the Russian Air Force, there is a case to be made that these weapons have been introduced far too late in the conflict.

The Russian Air Force, including its fleet of new production aircraft (i.e., the Su-30, Su-34, and Su-35) has been severely attrited over the course of over two years of war. Beyond combat losses and losses stemming from accidents resulting from heavy usage, rushed maintenance, and fatigued crews, Russia is burning through the flight hours of its combat aircraft far faster than it can build new aircraft. This is particularly the case for its older aircraft produced in the late Soviet era or the immediate aftermath of the Soviet era. Soviet combat aircraft, including the engines used by these aircraft, were never built or upgraded with as long a service life as their Western counterparts. This dynamic has for the most part continued with Russian combat aircraft produced following the dissolution of the Soviet Union. As a result, Russia is on track to experience a major decline in the number of combat-ready aircraft at its disposal, with a growing number of airframes requiring complex, lengthy, and expensive overhauls, and other primarily older aircraft designs having too few flight hours available to justify such overhauls not least given the limitations in overhaul capacity and throughput.

Although the existence of standoff munitions in the form of the UMPK and UMPB can lower attrition rates by reducing exposure to Ukraine’s air defences, it does nothing about sustained wear from accumulating flight hours. Compounding the challenges that Russia faces, the Russian air force is forced to employ its aircraft in a particularly inefficient manner. Given the geography of the Russia-Ukraine War and the primary bases that Russian combat aircraft operate from, the average Su-34 sortie involving the release of four 500-kilogram aerial bombs equipped with the UMPK guidance and wing assembly, for example, is likely well under two hours in duration and aircraft likely fly no more than 300 kilometers before releasing guided glide bombs (against preprogrammed targets) and returning to base. It is, as such, simply a waste of jet fuel and the precious flight hours left on airframes to employ modernized guided glide bombs in such a manner if a ground-launched UMPB employing a 300 mm rocket booster from the BM-30 Smerch artillery rocket system can not only do the same but also readily attack targets up to 150 or more kilometers behind the frontliens on short notice.

If it is assumed that the UMPB unitary guided glide bomb costs more or less the same in its air-launched and reported ground-launched configurations (excluding the solid rocket booster from the BM-30), the question of economic efficiency is shaped by the cost of operating a Su-34 (or another aircraft type) to fly no more than 300 kilometers to release up to six UMPB guided glide bombs before returning to base versus employing a single BM-30 launcher to use just 6 of its 12 barrels to launch ground-launched UMPBs. All things equal, reusable aircraft tend to be more cost-effective in the (indefinite) long run as long as attrition rates remain low. All things are not, however, equal for the Russian military in 2024. Even if a ground-launched UMPB is more expensive, it strains credulity to suggest that, assuming comparable production output for air-launched and ground-launched versions of the UMPB guided glide bomb, Russia will experience greater difficulty in increasing the output of 300 mm rocket boosters (i.e., without warheads) than increasing the production and/or overhaul output of combat aircraft, something that it has clearly struggled with before the Russia-Ukraine War and the dramatic expansion of sanctions and export controls. Russia, therefore, faces strong incentives to develop a ground-launched UMPB even amidst signs of the forthcoming widespread employment of this new guided glide bomb by Russian combat aircraft.

Reports of a ground-launched UMPB version being under development may amount to inaccurate rumours and it is possible that Russia’s research and development efforts in this area are unsuccessful. Should a ground-launched UMPB be developed, however, it will likely have outsize effects on the trajectory of the Russia-Ukraine War. In principle, several BM-30 batteries distributed along the frontline will be able to greatly reduce the pressure on the Russian Air Force to generate a high number of daily sorties. Instead, the Russian Air Force can be held in reserve to support offensives and preserve force structure for use following the eventual freezing or termination of the Russia-Ukraine War. Ground-launched UMPB guided glide bombs will likely also improve Russia’s ability to attack time-sensitive targets and, as a system likely to be operated by the Russian Army, can be more readily assigned to support the commanders of army divisions and corps than Russian Air Force aircraft.

Will Russia be able to ramp up and sustain high-volume production of the UMPB?

Ultimately, perhaps the most important factor determining the implications of the UMPB on the trajectory of the Russia-Ukraine War concerns whether Russia will be able to both ramp up and sustain high-volume production. Russia is known to be heavily reliant upon imported electronic components and this is likely to also apply to the new UMPB. With the UMPK guidance and wing assembly, usage was on a limited scale until several months after it was unveiled in early 2023. By the winter of 2023, however, the UMPK became increasingly ubiquitous and contributed to the success of several Russian offensives with multiple reports of peak expenditures of well over one hundred UMPK-equipped bombs per day in the spring of 2024.

Russia may be able to ramp up UMPB production more quickly than was the case for the UMPK, but as long as Russia is reliant on the import of electronic components, the ability to sustain high-volume production of the UMPB will likely be affected by the effectiveness of sanctions and export controls. It is therefore an open question whether Russia will be able to build and transfer to frontline forces the several thousand UMPB that it likely requires per month. To put these numbers into context, a force of just 50 Russian aircraft undertaking a single sortie per day with an average of just four guided glide bombs will require 6000-6200 guided glide bombs per month (i.e., over 70,000 per year). To undertake an average of one sortie per day with 6 guided glide bombs, or two sorties per day with 4 guided glide bombs, Russia will respectively require 9000-9300 or 12,000-12,400 guided glide bombs per month. If a ground-launched version of the UMPB is developed, then 4-6 BM-30 units equipped with 12 launchers, each of which can carry up to 12 rockets, will require similarly large numbers of UMPB guided glide bombs mounted on 300 mm diameter rocket boosters.

As of May 2024, anything close to a six-figure annual production output for the new UMPB guided glide bomb may appear fanciful but Russia has managed to dramatically increase military industrial output in a highly curated subset of areas. UMPB guided glide bombs are, of course, far more expensive, and complex to produce than standard artillery shells, and the INS+GNSS guidance system used in the UMPB is likely to be the most important production bottleneck. Russia may not succeed in dramatically increasing production of the UMPB but, in many respects, it has no choice but to try, much like it had no choice but to double down on the earlier UMPK guidance and wing assembly despite its limitations. Hence, while it is possible that the UMPB may remain a niche and relatively uncommon weapon in the Russia-Ukraine War, in which case it will join the ranks of a large number of mainly powered standoff munitions employed by the Russian Air Force, it is also possible that the UMPB will be used in progressively increasing numbers in much the same manner as the earlier UMPK.

Will the UMPB remain effective in the face of advances in electronic warfare?

The UMPB is likely a welcome if belated, addition to Russia’s military capabilities. Like its closest American counterpart, the JDAM system, it is not, however, a magical weapon. The effectiveness of the relatively low-cost approach to unpowered standoff munitions reflected in the UMPK, UMPB, and the JDAM, among others, is dependent on the resilience of the onboard GNSS receiver in the face of adversary efforts in electronic warfare which includes both the jamming and spoofing of GNSS signals. INS systems, which are built to a wide range of standards and, as such, to a wide range of price points, are intrinsically susceptible to drift over time and guided glide bombs have a fairly long flight time when employed over meaningful standoff ranges of 50 or more kilometers. Simply stated, this approach to guided bomb technology only works for as long as the onboard GNSS receiver has access to accurate and reliable GNSS positioning data.

As of May 2024, the earlier UMPK system reportedly remains mostly effective in the face of Ukrainian electronic warfare efforts. At the same time, reports indicate that Russian electronic warfare has degraded the accuracy and, as such, the effectiveness of a wide range of Western guided munitions transferred to Ukraine that similarly rely upon accurate and reliable GNSS positioning data to correct for the drift of the onboard INS. Going forward, Ukraine is likely to focus on improving its electronic warfare capabilities to counter the growing threat posed by Russia’s guided glide bombs. Should Ukrainian electronic warfare degrade the ability of the UMPB’s onboard GNSS antenna assembly to receive accurate and reliable GNSS positioning data, then the accuracy and, as such, effectiveness of the UMPB is likely to decline. If – perhaps when – this happens, Russia, like Ukraine and other countries, will either have to develop and introduce a more resilient GNSS antenna assembly or turn to far more complex and more expensive standoff munitions that are less reliant on the availability of accurate and reliable GNSS positioning data. This includes standoff munitions equipped with more advanced – and more expensive – inertial navigation systems, electro-optical terminal sensors, and Digital Scene Matching Area Correlators (DSMAC). These are the types of components used in Russia’s various land-attack cruise missiles and it stands to reason that if Russia did not face major bottlenecks in the production output of these and other cruise missile components, Russia’s output of laand-attack cruise missiles would be higher, the use of cruise missiles more widespread, and guided glide bombs like the UMPK and UMPB would not have become so critical to Russia’s war effort.

All things considered, Russia's new UMPB guided glide bomb may be effective for a time but, in the longer run, Russia will likely require more complex and more expensive standoff munitions including guided glide bombs, and this will likely mean a return to prominence of the very barriers of entry that limited Russia’s adoption of guided air-to-ground munitions before Russia invaded Ukraine in February 2022. This dynamic is, of course, unlikely to rapidly transpire in the coming weeks or even the coming months. The main takeaway is that the UMPB, like its international counterparts, is not a magical omnipotent and uncounterable weapon, and it will likely be subjected to an intensifying multi-faceted measure-countermeasure competition. The implications of the introduction of the UMPB on the trajectory of the Russia-Ukraine War will therefore likely also be shaped by factors that are largely outside of Russia’s control.