Supersonic

Japan’s Ministry of Defense has included an intriguing description of the ASM-3 Kai missile in its record fiscal year 2027 defense budget request, referring to the weapon as an “air-to-surface/anti-air missile.” Until now, the ASM-3 family has been publicly associated with the air-launched anti-ship (anti-surface) mission, and the wording potentially hints at an additional capability or intended role for the upgraded weapon.

The reference appears in Japan’s FY2027 defense budget request, submitted today, which seeks a record ¥8.89 trillion (approximately $56 billion) for the fiscal year beginning in April 2027. The request is part of a broader push by Tokyo to expand standoff strike, air defense, uncrewed systems, and other advanced capabilities.

The reference appears under a sub-section entitled Durability and Resilience, which calls for funds to “secure ammunition and fuel, increase the number of operational units (by addressing parts shortages, etc.), enhance the resilience of facilities (through facility upgrades associated with the formation of new units and the introduction of new equipment, etc.), and strengthen the operational infrastructure (by enhancing manufacturing capabilities, etc.).”

In terms of securing ammunition, the document highlights the breadth of weapons systems involved, ranging from 5.56mm small arms ammunition and 30mm cannon rounds, via 155mm precision artillery rounds, up to advanced missiles including the Type 23 ship-launched air defense missile and the ASM-3 Kai.

The Mitsubishi Heavy Industries (MHI) ASM-3 is Japan’s domestically developed supersonic air-launched anti-ship missile, originally intended to arm the Mitsubishi F-2 fighter. The improved ASM-3 Kai (“Kai” meaning modified or revised) represents a significant evolution of the weapon, although the full nature of its capabilities and performance have not been officially revealed. The missile has already been observed undergoing testing on F-2s.

The ASM-3 program has also gone through a number of different configurations over its development history, with at least five distinct external configurations identified in previous reporting. The existence of multiple iterations leaves open the possibility that the newly identified “anti-air” designation could ultimately correspond to a dedicated air-to-air variant or derivative of the ASM-3 family, rather than simply a secondary capability of the baseline ASM-3 Kai.

Reportedly, the ASM-3 Kai is capable of flying more than 400 kilometers (about 250 miles), although the exact range of the operational weapon remains classified. It is powered by a ramjet engine, giving it sustained high-speed performance — reportedly around Mach 3. If it indeed has an air-to-air capability, this would be an advantage in some scenarios, compared to relying solely on a brief but very powerful rocket boost as many air-to-air missiles do.

The weapon is also understood to employ an active/passive radar seeker, providing it with both an active radar mode for detecting and engaging targets and a passive mode that can home in on their electromagnetic emissions. While an active radar seeker is common on long-range air-to-air missiles, the latter passive capability could also be of extreme value in an air-to-air application.

The ASM-3 is also a substantially larger missile than typical fighter-launched air-to-air weapons. While that imposes obvious carriage and aerodynamic penalties, it also allows for a larger propulsion system, seeker, and warhead than would be practical in a smaller missile.

A weapon capable of traveling hundreds of miles at high speed, while carrying an active/passive radar seeker, could potentially be especially useful against high-value airborne assets such as airborne early warning and control (AEW&C) aircraft. These platforms provide vital wide-area surveillance, battle management, and targeting capabilities. At the same time, their powerful radars are necessarily emitting, potentially making them detectable and trackable by a missile employing a passive seeker.

China’s rapidly expanding AEW&C fleet is an increasingly important part of its ability to generate situational awareness, coordinate fighters, and extend its sensor coverage well beyond its immediate borders. The force, which already numbers dozens of increasingly capable fixed-wing aircraft, is a growing operational challenge for Japan and other regional air forces.

The ability to threaten such aircraft from well beyond the range of conventional air-to-air engagements could force an opponent to operate its AEW&C fleet even further from contested airspace, reducing the effectiveness of its sensors and command-and-control architecture. Although a passive seeker could also offer an avenue for homing in on relevant radar emissions, exactly how the ASM-3 Kai’s seeker would operate against airborne targets is not publicly known. Equally, a different variant of the missile, optimized for anti-air missions, could incorporate both passive and active seekers specially adapted for that mission set, although it is very possible a single configuration can accomplish both missions. As well as AEW&C aircraft, such a missile would be just as relevant for other high-value, non-maneuvering targets at long ranges, including intelligence-gathering platforms, tankers, and other support aircraft.

The budget language by itself falls short of establishing whether the ASM-3 Kai has been tested or validated against aircraft. The designation could reflect a broader classification within the budget documents, or it could point toward a genuine expansion of the weapon’s intended target set.

XASM-3 Supersonic anti-ship missile test launch

Such a weapon would not necessarily be a replacement for Japan’s existing air-to-air missile arsenal. Instead, an “anti-air” ASM-3 Kai could occupy a specialized niche focused on high-value or otherwise particularly important airborne targets at extended ranges.

The possibility is consistent with Japan’s broader effort to expand the flexibility and reach of its air-launched weapons. Tokyo is pursuing a growing family of standoff weapons as part of a major expansion of its counterstrike and deterrence capabilities, including longer-range missiles capable of striking targets well beyond the immediate vicinity of Japan.

Other air-to-air missiles mentioned in the same section of the document comprise the U.S.-made AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM) and the domestically developed AAM-4B, another medium-range weapon, thought to be the first of its kind to be fitted with an active electronically scanned array (AESA) antenna.

Between the exclusive AESA radar and Japan’s labour cost, Mitsubishi’s AAM-4B might be the most expensive air-to-air missile on the planet pic.twitter.com/rfBnXB8RzS

— Lia Wong (@LiaWong__) May 3, 2022

The FY2027 defense budget request also mentions another apparently new air-launched weapon for Japan, the AGM-88G Advanced Anti-Radiation Guided Missile-Extended Range (AARGM-ER). Japan has not previously been publicly documented as an international AARGM-ER customer, but the weapon would be an obvious candidate for integration with its F-35 fighters if it wishes to bolster their suppression/destruction of enemy air defenses (SEAD/DEAD) capabilities.

In terms of F-2-related developments, the document calls for the upgrade of an initial 10 of these aircraft to make them compatible with the air-launched version of the Upgraded Type 12 anti-ship guided missile, a significant new weapon that you can read more about here.

TWZ has contacted Japan’s Ministry of Defense seeking clarification on the “air-to-surface/anti-air” designation and what it means for the ASM-3 Kai’s intended capabilities and target set. It could also be the case that the description is an error in the budget document.

However, the emergence of such a capability would also come at a time when very-long-range air-to-air weapons are becoming increasingly important as anti-access/area-denial challenges make it harder for fighters to get close to enemy aircraft and the high-value assets supporting them. China has fielded weapons such as the PL-15 and the much larger PL-17, while the United States is developing the AIM-260 and has just revealed the AIM-424 Malice, a U.S. Navy missile reportedly capable of reaching more than 250 nautical miles. The U.S. Navy is also fielding the AIM-174B, a very-long-range weapon developed very much with the Chinese threat in mind, and which we discuss in the video below.

How The Navy’s New Very Long-Range AIM-174 Will Pierce China’s Anti-Access Bubble

For now, exactly what prompted the “air-to-surface/anti-air” designation for the missile is unclear, but if it reflects a genuine expansion of the ASM-3 Kai’s mission set, it would represent a particularly interesting development in Japan’s rapidly evolving air-launched weapons portfolio.

Hat-tip to Yoshihiro Inaba for bringing this development to our attention.

Contact the author: thomas@thewarzone.com

Saab has unveiled its roadmap for its Autonomous Collaborative Platform (ACP) program, a stealthy, supersonic ‘fighter drone,’ which could enter service in the 2030s with the Swedish Air Force and potentially other customers. The aerospace and defense company is already working on two uncrewed technology demonstrators and today presented a full-scale mock-up of an operational drone that those two aircraft could inform. This drone, compared to the U.S. Air Force Collaborative Combat Aircraft (CCA), for example, is a higher-end proposition, more advanced, larger, and with superior performance than those being test flown in the United States.

TWZ was among other members of the media who were briefed on the ACP program by Peter Nilsson, the head of Saab’s Advanced Programs business unit. He was talking at Malmen Air Base in Sweden, during an event to celebrate the Swedish Air Force’s 100th anniversary.

As for the name, Nilsson confirmed that, before settling on ACP, Saab had used the Collaborative Combat Aircraft (CCA) and Unmanned Aerial System (UAS) nomenclature. Meanwhile, the ACP falls under Sweden’s overarching KFS project, which stands for Koncept för Framtida Stridsflygplan, or Concept for Future Combat Aircraft.

The most significant element of the announcement was the full-scale mock-up of what Saab is calling aircraft A3. The idea of this is to show how a potential high-end ACP could look, and the kinds of capabilities it might bring, provided the company is awarded a development contract.

Broadly speaking, aircraft A3 has a lot in common with a previous concept that the company released back in 2024.

The concept retains the same tailless, stealthy configuration, with significant internal capacity for fuel and internal stores. The stealthy, chisel-type DSI air intakes remain on either side of the fuselage, but the prominent bulge roughly above where the engine nozzle would be is removed. The overall geometry remains similar: a sleek, blended wing/body configuration with cropped wings and a prominent chine running around the arrow-like forward edges, giving it something of a resemblance to the Cold War-era Saab Draken fighter, with its distinctive double-delta wing.

In the meantime, Saab is working on aircraft A1 and A2, uncrewed technology demonstrators that are being funded by the Swedish Ministry of Defense.

The first of these, A1, is expected to fly within the next 15 months,” according to Nilsson. The defense ministry called upon Saab to “go from concept to first flight within 36 months,” providing what Nilsson described as a “quite challenging” timeline.

Aircraft A1 uses the same GE Aerospace F414 engine that powers the Saab Gripen E/F crewed fighter. The turbofan produces around 22,000 pounds of thrust and will ensure A1 has supersonic performance.  However, for Saab, the main goal of A1 is to demonstrate that the company can build and fly a low-observable drone.

Saab provided imagery of wind-tunnel models of the A1. Overall, it appears loosely similar to the A3 mockup, with the exception of the twin, outward-canted tailfins. Aircraft A1 will have capacity for an internal weapons bay, although it will not be used for stores release tests. The next test article, aircraft A2 will have an internal weapons bay, and will presumably be used to test ordnance. Otherwise, A2 will be used for tests of other advanced technologies, including new materials and sensors.

No artwork of aircraft A2 was provided, but Nilsson said it will be “not quite” identical to A1, in terms of appearance. It will also be powered by the F414.

The F414 was selected due to its availability and the fact that the company has plenty of experience with the engine due to the Gripen E/F program. Saab is looking at other potential powerplants for the A3, but acknowledged that, should Sweden buy a productionized ACP, the engine commonality would be a big advantage, including, for example, when an engine needs to be changed at a remote airbase. This kind of maintenance is central to the Gripen concept of operation and would be retained for the ACP.

Saab is contracted until 2030 to develop the A1 and A2 demonstrators. What happens next will depend on the Swedish Ministry of Defense, and there is currently no agreement for a follow-on ACP contract, which would see the design advanced to a production-oriented prototype like the A3.

“We have floated the view that this would be a great asset to the Gripen E, but right now there is no commitment,” Nilsson remarked. Saab envisages the Gripen E serving as a tactical mission commander for one or more ACPs, working in conjunction with the company’s GlobalEye airborne early warning and control (AEW&C) aircraft, a type also ordered by Sweden. Outside of Sweden, the drone could work with a wide variety of other crewed platforms, too.

Pending investment from the Swedish government, Saab may decide to use its own funds for early development of the A3. However, Nilsson noted that “if a customer does not come along I don’t know when my CEO will stop me spending — you need a customer to buy into this.”

Saab’s broader ACP vision is based on an advanced platform that offers both low-observable features and supersonic performance.

The resulting drone should be capable of undertaking “high-risk missions in heavily defended airspace.” As well as air-to-air combat, missions would include electronic warfare, suppression of enemy air defenses, and deep precision strike.

If Sweden buys into the idea, a development contract could be expected around 2030. Thereafter Saab thinks it could have the A3 aircraft in the air sometime in the early 2030s, leading to initial operational capability from the mid-2030s.

With the ACP program, Saab hopes to stake its claim as the “first-mover in the segment” for high-end ‘loyal wingman’-type aircraft.

But even if the Swedish Air Force isn’t swayed by Saab’s ACP offer, the company is seeing the related spiral development as fundamental to its future as a builder of crewed combat aircraft, too.

The same basic architecture now being developed for the ACP could provide a technological and conceptual base for a future (crewed) Gripen successor. This would be required by the Swedish Air Force sometime after 2055. If there is demand, Saab says it could start development of such an aircraft in the mid-2030s.

A rendering of a potential future crewed combat aircraft that appeared in Saab’s presentation reveals a slightly more detailed version of a concept shown in the past. Namely, a design apparently tailored for high speed, as well as low observability. Some of the same features found in the A3 concept — notably the overall blended wing/body and cropped wings — appear in the crewed combat aircraft, although this adds outward-canted tail surfaces, mounted on booms that project relatively far beyond the engine nozzle. The nose and forward fuselage bear a resemblance to the F-35, and, overall, the aircraft seems to be around the same size as the U.S. design, perhaps a little larger.

For its part, the Swedish Air Force is still weighing up whether it wants to pursue a crewed successor to the Gripen, if it will abandon crewed fighters altogether, or if it will seek to join a foreign sixth-generation fighter program. A decision on this is likely sometime between 2028 and 2030.

Speaking to journalists at Malmen today, Brigadier-General Niclas Magnusson, the deputy commander of the Swedish Air Force, called for closer collaboration between the service and industry as Sweden seeks to define its future air combat requirements.

“We have to research and find the limits of what we are able to do,” Magnusson said, adding that he expected the future Swedish Air Force to field both crewed and uncrewed platforms.

That decision is still to come but will also be informed by the relative costs of the Gripen (more of which may still be acquired), higher-end drones, and potential future crewed platforms.

When it comes to the ACP, Nilsson suggested that the life-cycle cost will be around a third that of the Gripen, although acquisition cost won’t be as low as that.

“The problem is that this bloody aircraft is too low cost,” Nilsson added, pointing to the Gripen E.

Ultimately, the cost of the ACP will depend on the degree of capability that the customer demands.

Potentially, a single ACP could cost half as much as a Gripen. Open-source reports suggest that the Gripen E typically comes with a flyaway cost of roughly $70-80 million.

If the ACP is to offer “high-end survival,” Nilsson explained, then a customer would likely be able to field two to three ACPs for each Gripen. The ratio “is not one to 10.”

While Saab also wants to offer the ACP to other Gripen E/F operators as a priority, the fate of the program remains heavily dependent on larger questions about the future of the Swedish Air Force.

The program gives Saab a solid, and potentially unique, entrance into the CCA space. As we’ve said for years, fourth-generation fighters can remain highly relevant when paired with CCAs — and with a drone as advanced as this, potentially even more so.

The ACP will still come with a significant cost, but that could be offset by reducing or eliminating the need for a fifth- or sixth-generation crewed fighter for certain air forces.

For now, Saab’s high-end loyal wingman remains a proposal rather than a committed production program, but the company is clearly positioning it as more than another experimental drone. The A1 and A2 demonstrators are intended to prove the technologies needed for a survivable, supersonic, low-observable uncrewed aircraft, while the A3 concept unveiled today illustrates where Saab believes those technologies could ultimately lead.

Whether Stockholm opts for a new Saab-developed crewed fighter, joins an international sixth-generation program, or moves toward a force built around a greater mix of crewed and uncrewed aircraft, the ACP work gives the country a way to explore those possibilities without committing to one of them yet.

Contact the author: thomas@thewarzone.com