development

The U.S. Navy and U.S. Air Force are working on a new “Compact Variant” of the AIM-9X Sidewinder. The smaller Sidewinder is being developed with a focus on increased magazine depth when carried internally by “advanced aircraft,” while also offering improved range and performance.

The Navy manages the Sidewinder program in cooperation with the Air Force. The Navy is asking for $83.3 million for work on the AIM-9X Compact Variant (CV) in its 2027 Fiscal Year budget request. The AIM-9X CV is also mentioned in the Air Force’s proposed budget for the 2027 Fiscal Year, but with the caveat that it does not plan to contribute funding explicitly toward its development until Fiscal Year 2028.

Current-generation Block II and Block II+ subvariants AIM-9X are already highly capable imaging infrared (IIR) guided anti-air missiles. They have thrust-vectoring, high-off-boresight targeting, lock-on-after-launch, and other capabilities that you can read more about in detail here.

Risk reduction work on the AIM-9X CV has already been underway since Fiscal Year 2025. However, the new version does not appear to have been mentioned by name in prior Navy or Air Force budgets. Previous funding was contained under the umbrella of the larger System Improvement Plan IV (SIP IV) upgrade effort.

“The AIM-9X CV repackages the SIP IV technology into a compact airframe optimized for internal carriage on advanced aircraft with improved kinematic performance,” according to the Navy’s Fiscal Year 2027 budget request. “The program will deliver increased capability to the warfighter with greater standoff range, increased aircraft weapon station capacity, and maintains inner boundary performance.”

In Fiscal Year 2027, the goal is that “the program will advance hardware and software designs. This effort will focus on design and development of critical hardware components and compatibility with advanced platforms,” the budget documents add. “The overall scope includes platform integration, material and energetics studies, and extensive modeling, simulation, and analysis. Activities will also incorporate system safety analysis, the establishment of requisite integration and test environments, risk- reduction testing, and other engineering efforts necessary to mature the complete system baseline.”

The Navy and Air Force budget documents do not offer any further details about the AIM-9X CV’s configuration, or how it will achieve “greater standoff range” and “improved kinematic performance” in a more compact package. How truncated the AIM-9X CV’s airframe, as well as its control surfaces, might be compared to existing versions is also unknown. The core AIM-9X design is already relatively short and narrow by anti-air missile standards at just under 10 feet long and five inches in diameter (not including its fins). For comparison, all variants of the AIM-120 Advanced Medium-Range Air-to-Air Missile (AMRAAM) are some 12 feet long and have bodies that are around seven inches in diameter.

The Navy and the Air Force previously considered developing a Block III variant of the AIM-9X, which could have included a highly loaded grain rocket motor. Though the Block III effort was shelved, at least publicly, the Navy has continued to make significant investments in this kind of rocket technology with a general eye toward improved range and performance for future missiles.

“The Next-Generation Highly Loaded Grain project team has matured the technology and seeded the development of future mission-modular propulsion systems that can increase weapon ranges by up to 1.5x while maintaining inner boundaries for short-range and time-critical missions,” according to one factsheet detailing notable achievements by NAVAIR’s Naval Air Warfare Center Weapons Division (NAWCAD) in 2023.

The benefits of greater reach and better kinematic performance, even in the AIM-9X’s existing form factor, are clear-cut. As the Navy and Air Force budget documents highlight, putting all that in a smaller package offers additional value from a magazine depth perspective. If an aircraft can carry multiple AIM-9X CVs on stations that can only accommodate one standard-size version, that means more engagement opportunities per sortie without any change to the rest of the loadout.

This is all especially important for stealthy aircraft that carry stores in internal bays with rigid dimensions when flying in their most low-observable configurations. As an example of what this means in practical terms, Lockheed Martin has spent years now working to develop a capability called Sidekick to increase the total number of AIM-120s that F-35s can carry in their weapons bays from four to six. Even so, that upgrade will only apply to A and C variants of the jet, as the bays on the B model are smaller to begin with.

The expectation that the AIM-9X CV will offer improved capabilities over its predecessors is also significant. The Air Force, in particular, has explored several concepts for air-to-air missiles that are smaller than Sidewinder, but which have generally been understood to trade range and/or performance for added magazine depth.

All of this brings us to the matter of Collaborative Combat Aircraft (CCA) type drones, which impose additional constraints on weapons integration simply by virtue of their overall size and maximum takeoff weight. As described now, the AIM-9X CV might be well-suited for arming CCAs, which will have more limited internal and external stores capacity, overall, compared to traditional crewed tactical jets. Being able to load them with more total missiles per sortie, and increase their reach at the same time, would be a major boon.

The Air Force just recently started weapons integration work as part of its CCA program using Anduril’s YFQ-44A Fury, which does not have an internal bay. Fury has been seen so far conducting flight tests loaded with a pair of inert AIM-120s, one under each wing.

The YFQ-44A is one of two designs the Air Force is currently flight testing under the first phase, or Increment 1, of its CCA program. The other is General Atomics YFQ-42A Dark Merlin, which can carry stores internally. The Air Force has also been experimenting with other relevant drone designs in recent years, including Kratos XQ-58A and Boeing’s MQ-28 Ghost Bat, the former of which also has an internal payload bay. More recently, the service assigned the YFQ-48A designation to Northrop Grumman’s Talon Blue drone.

It is worth noting here that the development of the MQ-28 originally began for the Royal Australian Air Force, which has conducted at least one live-fire AIM-120 shot from one of those drones. The Ghost Bat carried the missile externally in that test. Future versions of the design are set to include internal weapons bays.

Uncrewed MQ-28 Ghost Bat showcases its combat capability

Back in the United States, the Marine Corps’ first CCA is set to be a variant of the XQ-58, and the service is also leveraging the YFQ-42A to support its CCA plans. The Navy is still early in the process of exploring potential carrier-based CCA designs.

The AIM-9X CV might also open up other kinds of new operational possibilities. A compact anti-air missile could provide defensive capability against incoming missiles for larger aircraft. This is something the Air Force has been particularly interested in, including as a way to help better protect aerial refueling tankers.

The compact version’s overall benefits could make it attractive for employment as a surface-to-air weapon, as well. Full-size AIM-9Xs are already an interceptor option for several ground-based air defense systems in service or otherwise on the market globally today, including the U.S. Army’s Enduring Shield.

With the development of the AIM-9X CV now fully out in the open, more details about the missile’s design, as well as how the Navy and Air Force might plan to field it, may now begin to emerge.

Contact the author: joe@twz.com

April 24 (UPI) — Maine Gov. Janet Mills on Friday vetoed a bill that would have paused artificial intelligence data center construction in the state for 18 months.

Mills said she decided to veto it because it would have potentially harmed a permitted and in progress data center expected to create hundreds of jobs, both for construction and once the center opens.

The project, a $550 million data center in Jay, Maine, is a multi-year effort to redevelop the former Androscoggin Mill, which was damaged in a 2020 boiler explosion and then closed in 2023, took with it hundreds of jobs and 22% of the town’s tax revenue.

The bill would have been the first in the country restricting or slowing the spread of large-scale data centers required for power-hungry AI systems, which have driven up the cost of both electricity and water for residents living near them, NBC News and Politico reported.

“A moratorium is appropriate given the impacts of massive data centers in other states on the environment and electricity rates,” Mills said in a press release.

“But the final version of this bill fails to allow for a specific project in the Town of Jay that enjoys strong local support from its host community and region,” she said.

There are more than 5,000 data centers in the United States — more than any country in the world — and that number has grown significantly in the last four years as artificial intelligence has become a focus the tech industry.

While many state and local leaders have started to respond to concerns among residents about the huge amounts of electricity needed to power AI data centers and the huge amounts of water needed to keep them cool, as have some members of Congress.

As states have contemplated increased regulation and scrutiny from tech and AI companies, President Donald Trump at the same time has worked to keep the cuffs of tech companies because they “must be free to innovate without cumbersome regulation,” he said in December.

“Excessive state regulation thwarts this imperative,” Trump said in an executive order meant to prevent states from creating new regulations.

Mills said she worked with Maine’s legislature to carve out an exemption for the data center in Jay but was unsuccessful, so she vetoed the law.

The development in Jay, she said, is under contract and permitted, and is expected to create 800 construction jobs, more than 100 high-paying permanent jobs and “substantial tax revenue” for the Town of Jay.

In a letter informing the legislature that she planned to veto the bill, Mills said she plans to issue an executive order to establish a council to study the impacts — real and potential — of data centers in Maine.

“I believe it necessary and important to examine and plan for the potential impacts of large-scale data centers in Maine, as the use of artificial intelligence becomes more widespread,” Mills said.

“Given the serious conversations about data centers here and around the country, I believe this work should commence without delay,” she told legislators.