That second jet was piloted by artificial intelligence, with the Air Force’s highest-ranking civilian riding along in the front seat. It was the ultimate display of how far the Air Force has come in developing a technology with its roots in the 1950s. But it’s only a hint of the technology yet to come.

The United States is competing to stay ahead of China on AI and its use in weapon systems. The focus on AI has generated public concern that future wars will be fought by machines that select and strike targets without direct human intervention. Officials say this will never happen, at least not on the U.S. side. But there are questions about what a potential adversary would allow, and the military sees no alternative but to get U.S. capabilities fielded fast.

“Whether you want to call it a race or not, it certainly is,” said Adm. Christopher Grady, vice chairman of the Joint Chiefs of Staff. “Both of us have recognized that this will be a very critical element of the future battlefield. China’s working on it as hard as we are.”

A look at the history of military development of AI, what technologies are on the horizon and how they will be kept under control:

From machine learning to autonomy

AI’s roots in the military are actually a hybrid of machine learning and autonomy. Machine learning occurs when a computer analyzes data and rule sets to reach conclusions. Autonomy occurs when those conclusions are applied to take action without further human input.

This took an early form in the 1960s and 1970s with the development of the Navy’s Aegis missile defense system. Aegis was trained through a series of human-programmed “if/then” rule sets to be able to detect and intercept incoming missiles autonomously, and more rapidly than a human could. But the Aegis system was not designed to learn from its decisions and its reactions were limited to the rule set it had.

“If a system uses ‘if/then,’ it is probably not machine learning, which is a field of AI that involves creating systems that learn from data,” said Air Force Lt. Col. Christopher Berardi, who is assigned to the Massachusetts Institute of Technology to assist with the Air Force’s AI development.

AI took a major step forward in 2012 when the combination of big data and advanced computing power enabled computers to begin analyzing the information and writing the rule sets themselves. It is what AI experts have called AI’s “big bang.”

The new data created by a computer writing the rules is artificial intelligence. Systems can be programmed to act autonomously from the conclusions reached from machine-written rules, which is a form of AI-enabled autonomy.

Testing an AI alternative to GPS navigation

Air Force Secretary Frank Kendall got a taste of that advanced warfighting this month when he flew on Vista, the first F-16 fighter jet to be controlled by AI, in a dogfighting exercise over California’s Edwards Air Force Base.

While that jet is the most visible sign of the AI work underway, there are hundreds of ongoing AI projects across the Pentagon.

At MIT, service members worked to clear thousands of hours of recorded pilot conversations to create a data set from the flood of messages exchanged between crews and air operations centers during flights, so the AI could learn the difference between critical messages like a runway being closed and mundane cockpit chatter. The goal was to have the AI learn which messages are critical to elevate to ensure controllers see them faster.

In another significant project, the military is working on an AI alternative to GPS satellite-dependent navigation.

In a future war, high-value GPS satellites would likely be hit or interfered with. The loss of GPS could blind U.S. communication, navigation and banking systems, and make the U.S. military’s fleet of aircraft and warships less able to coordinate a response.

So last year the Air Force flew an AI program — loaded onto a laptop that was strapped to the floor of a C-17 military cargo plane — to work on an alternative solution using the Earth’s magnetic fields.

Experts already knew that aircraft could navigate by following the Earth’s magnetic fields, but so far that hasn’t been practical because each aircraft generates so much of its own electromagnetic noise that there hasn’t been a good way to filter out everything but the Earth’s emissions.

“Magnetometers are very sensitive,” said Col. Garry Floyd, director for the Department of Air Force-MIT Artificial Intelligence Accelerator program. “If you turn on the strobe lights on a C-17, we would see it.”

The AI learned, through the flights and reams of data, which signals to ignore and which to follow. The results “were very, very impressive,” Floyd said. “We’re talking tactical airdrop quality.”

“We think we may have added an arrow to the quiver in the things we can do, should we end up operating in a GPS-denied environment. Which we will,” Floyd said.

The AI so far has been tested only on the C-17. Other aircraft will also be tested. If it works, it could give the military another way to operate if GPS goes down.

Safety rails and pilot-speak

Vista, the AI-controlled F-16, has considerable safety rails as the Air Force trains it. There are mechanical limits that keep the still-learning AI from executing maneuvers that would put the plane in danger. There is a safety pilot, too, who can take over control from the AI with the push of a button.

The algorithm cannot learn during a flight, so each time it goes up, it has only the data and rule sets created from previous flights. When a new flight is over, the algorithm is transferred back onto a simulator, where it is fed new data gathered in-flight to learn from, create new rule sets and improve its performance.

But the AI is learning fast. Because of the supercomputing speed AI uses to analyze data, and then flying those new rule sets in the simulator, its pace in finding the most efficient way to fly and maneuver has already led it to beat some human pilots in dogfighting exercises.

Safety is still a critical concern, and officials said the most important way to take safety into account is to control what data is reinserted into the simulator for the AI to learn from. In the jet’s case, it’s making sure the data reflects safe flying. Ultimately the Air Force hopes that a version of the AI being developed can serve as the brain for a fleet of 1,000 unmanned warplanes under development by General Atomics and Anduril.

In the experiment training AI on how pilots communicate, the service members assigned to MIT cleaned up the recordings to remove classified information and the pilots’ sometimes salty language.

Learning how pilots communicate is “a reflection of command and control, of how pilots think. The machines need to understand that too if they’re going to get really, really good,” said Grady, the Joint Chiefs vice chairman. “They don’t need to learn how to cuss.”

AI marks one of the biggest advances in military aviation since the introduction of stealth in the early 1990s, and the Air Force has aggressively leaned in. Even though the technology is not fully developed, the service is planning for an AI-enabled fleet of more than 1,000 unmanned warplanes, the first of them operating by 2028.

It was fitting that the dogfight took place at Edwards Air Force Base, a vast desert facility where Chuck Yeager broke the speed of sound and the military has incubated its most secret aerospace advances. Inside classified simulators and buildings with layers of shielding against surveillance, a new test-pilot generation is training AI agents to fly in war. Kendall traveled here to see AI fly in real time and make a public statement of confidence in its future role in air combat.

“It’s a security risk not to have it. At this point, we have to have it,” Kendall said in an interview with The Associated Press after he landed. The AP, along with NBC, was granted permission to witness the secret flight on the condition that it would not be reported until it was complete because of operational security concerns.

The AI-controlled F-16, called Vista, flew Kendall in lightning-fast maneuvers at more than 550 miles an hour that put pressure on his body at five times the force of gravity. It went nearly nose-to-nose with a second human-piloted F-16 as both aircraft raced within 1,000 feet of each other, twisting and looping to try force their opponent into vulnerable positions.

At the end of the hourlong flight, Kendall climbed out of the cockpit grinning. He said he’d seen enough during his flight that he’d trust this still-learning AI with the ability to decide whether or not to launch weapons in war.

There’s a lot of opposition to that idea. Arms control experts and humanitarian groups are deeply concerned that AI one day might be able to autonomously drop bombs that kill people without further human consultation, and they are seeking greater restrictions on its use.

“There are widespread and serious concerns about ceding life-and-death decisions to sensors and software,” the International Committee of the Red Cross has warned. Autonomous weapons “are an immediate cause of concern and demand an urgent, international political response.”

Kendall said there will always be human oversight in the system when weapons are used.

The military’s shift to AI-enabled planes is driven by security, cost and strategic capability. If the U.S. and China should end up in conflict, for example, today’s Air Force fleet of expensive, manned fighters will be vulnerable because of gains on both sides in electronic warfare, space and air defense systems. China’s air force is on pace to outnumber the U.S. and it is also amassing a fleet of flying unmanned weapons.

Future war scenarios envision swarms of American unmanned aircraft providing an advance attack on enemy defenses to give the U.S. the ability to penetrate an airspace without high risk to pilot lives. But the shift is also driven by money. The Air Force is still hampered by production delays and cost overruns in the F-35 Joint Strike Fighter, which will cost an estimated $1.7 trillion.

Smaller and cheaper AI-controlled unmanned jets are the way ahead, Kendall said.

Vista’s military operators say no other country in the world has an AI jet like it, where the software first learns on millions of data points in a simulator, then tests its conclusions during actual flights. That real-world performance data is then put back into the simulator where the AI then processes it to learn more.

China has AI, but there’s no indication it has found a way to run tests outside a simulator. And, like a junior officer first learning tactics, some lessons can only be learned in the air, Vista’s test pilots said.

Until you actually fly, “it’s all guesswork,” chief test pilot Bill Gray said. “And the longer it takes you to figure that out, the longer it takes before you have useful systems.”

Vista flew its first AI-controlled dogfight in September 2023, and there have only been about two dozen similar flights since. But the programs are learning so quickly from each engagement that some AI versions getting tested on Vista are already beating human pilots in air-to-air combat.

The pilots at this base are aware that in some respects, they may be training their replacements or shaping a future construct where fewer of them are needed.

But they also say they would not want to be up in the sky against an adversary that has AI-controlled aircraft if the U.S. does not also have its own fleet.

“We have to keep running. And we have to run fast,” Kendall said.

The U.S. agreed to send 31 Abrams to Ukraine in January 2023 after an aggressive monthslong campaign by Kyiv arguing that the tanks, which cost about $10 million apiece, were vital to its ability to breach Russian lines.

But the battlefield has changed substantially since then, notably by the ubiquitous use of Russian surveillance drones and hunter-killer drones. Those weapons have made it more difficult for Ukraine to protect the tanks when they are quickly detected and hunted by Russian drones or rounds.

Five of the 31 tanks have already been lost to Russian attacks.

The proliferation of drones on the Ukrainian battlefield means “there isn’t open ground that you can just drive across without fear of detection,” a senior defense official told reporters Thursday.

The official spoke on the condition of anonymity to provide an update on U.S. weapons support for Ukraine before Friday’s Ukraine Defense Contact Group meeting.

For now, the tanks have been moved from the front lines, and the U.S. will work with the Ukrainians to reset tactics, said Joint Chiefs of Staff Vice Chairman Adm. Christopher Grady and a third defense official who confirmed the move on the condition of anonymity.

“When you think about the way the fight has evolved, massed armor in an environment where unmanned aerial systems are ubiquitous can be at risk,” Grady told the AP in an interview this week, adding that tanks are still important.

“Now, there is a way to do it,” he said. “We’ll work with our Ukrainian partners, and other partners on the ground, to help them think through how they might use that, in that kind of changed environment now, where everything is seen immediately.”

News of the sidelined tanks comes as the U.S. marks the two-year anniversary of the Ukraine Defense Contact Group, a coalition of about 50 countries that meets monthly to assess Ukraine’s battlefield needs and identify where to find needed ammunition, weapons or maintenance to keep Ukraine’s troops equipped.

Recent aid packages, including the $1 billion military assistance package signed by President Joe Biden on Wednesday, also reflect a wider reset for Ukrainian forces in the evolving fight.

This week’s assistance emphasized counter-drone capabilities, including .50-caliber rounds specifically modified to counter drone systems; additional air defenses and ammunition; and a host of alternative, and cheaper, vehicles, including Humvees, Bradley Infantry Fighting Vehicles and Mine Resistant Ambush Protected Vehicles.

The U.S. also confirmed for the first time that it is providing long-range ballistic missiles known as ATACMs, which allow Ukraine to strike deep into Russian-occupied areas without having to advance and be further exposed to either drone detection or fortified Russian defenses.

While drones are a significant threat, the Ukrainians also have not adopted tactics that could have made the tanks more effective, one of the U.S. defense officials said.

After announcing it would provide Ukraine the Abrams tanks in January 2023, the U.S. began training Ukrainians at Grafenwoehr Army base in Germany that spring on how to maintain and operate them. They also taught the Ukrainians how to use them in combined arms warfare — where the tanks operate as part of a system of advancing armored forces, coordinating movements with overhead offensive fires, infantry troops and air assets.

As the spring progressed and Ukraine’s highly anticipated counteroffensive stalled, shifting from tank training in Germany to getting Abrams on the battlefield was seen as an imperative to breach fortified Russian lines. Ukrainian President Volodymyr Zelenskyy announced on his Telegram channel in September that the Abrams had arrived in Ukraine.

Since then, however, Ukraine has only employed them in a limited fashion and has not made combined arms warfare part of its operations, the defense official said.

During its recent withdrawal from Avdiivka, a city in eastern Ukraine that was the focus of intense fighting for months, several tanks were lost to Russian attacks, the official said.

A long delay by Congress in passing new funding for Ukraine meant its forces had to ration ammunition, and in some cases they were only able to shoot back once for every five or more times they were targeted by Russian forces.

In Avdiivka, Ukrainian forces were badly outgunned and fighting back against Russian glide bombs and hunter-killer drones with whatever ammunition they had left.

Air Force Secretary Frank Kendall told senators on Tuesday at a hearing on the service’s 2025 budget that he will enter the cockpit of one of the F-16s that the service has converted for drone flight to see for himself how it performs in the air.

“There will be a pilot with me who will just be watching, as I will be, as the autonomous technology works,” Kendall told the Senate Appropriations Committee’s defense panel. “Hopefully neither he or I will be needed to fly the airplane.”

Drone warfare has quickly expanded from the sidelines of combat to one of its primary weapons. Drones are a daily threat in Ukraine and in the Middle East. In Ukraine, everyday citizens are targeted by Russian drones but also are assembling drones to collect video of Russian positions. In the Middle East, Iranian-backed Houthis and militant groups have regularly employed sophisticated air, sea and underwater drones to target U.S. bases and commercial ships in the Red Sea.

The Air Force began planning for its fleet of collaborative combat aircraft, or CCAs, several years ago, and it envisions a scenario in which one piloted jet will be able to quarterback multiple AI-driven, responsive drones, which the service calls “loyal wingmen.”

The service has been tight-lipped on what the fleet of drones will look like in size or platform, whether they will be full-size warplanes or something smaller. Kendall said the converted F-16 test flight will be done for him to observe the technology behind the future fleet.

The fleet is being designed specifically with future warfare, and potentially a conflict with China, in mind. China has rapidly modernized its anti-access capabilities as more sophisticated air defense systems make it risky to send manned crews too close. Drone aircraft could augment the service’s ability to breach those defenses, and they are envisioned to provide support in a variety of future missions such as surveillance or jamming.

“The initial role for the aircraft was going to be counter-air, but it will have the potential to do other things,” Kendall said.

The drone fleet is also expected to be cheaper than developing new manned jets, Kendall said. The current goal is to have each cost about a quarter to a third of what an F-35 fighter costs now, or about $20 million apiece.

Because of the crash, hundreds of Osprey aircraft across the Air Force, Marine Corps and Navy have been grounded since Dec. 6. There are two investigations that are looking into the Japan crash — a safety investigation board, which is a privileged internal review conducted in private to help inform pilots and crews, as well as an accident investigation board, which is the official administrative review. Both are still ongoing.

Separately, Air Force Special Operations Command is undergoing its own comprehensive review of its CV-22 Osprey program, and while the command has said it knows what failed, it has not made those details public.

“At this time, the material failure that occurred is known but the cause of the failure has not been determined. Engineering testing and analysis is ongoing to understand the cause of the material failure, a critical part of the investigation. Any disclosure of findings prior to investigations being finalized is premature and presumptive,” Air Force Special Operations Command said in a statement released Tuesday.

The Air Force, Navy and Marine Corps have been coordinating their efforts on when Osprey crews will be able to safely return to the skies. Each service will make its own determination, and the Air Force said to return its fleet of about 50 Ospreys to flight, “the priority is to inform our deliberate return to fly and ensure CV-22 aircrew and maintainers have the information they need to prevent future mishaps.”

The Osprey is a tiltrotor aircraft that can fly like both a helicopter and airplane.

Late Monday, NBC News reported that the crash was linked to chipping from the Osprey’s proprotor gearbox. When small pieces of metal chip off gears in the aircraft due to wear, it can generate dangerous metal debris that can damage engines. The gearbox has been under scrutiny in various Osprey accidents and some of its components have been wearing out quicker than expected. In January 2023, the Department of Defense awarded Bell-Boeing $12.7 million to improve the gearbox design across all of the Air Force, U.S. Marine Corps and Navy Osprey variants.

Air Force Special Operations Command was not available to comment on whether a gearbox chip caused the accident. However, it would not be the first time a chip issue was linked to an Air Force Special Operations Command Osprey mishap.

In July 2013, an Osprey experienced a proprotor gearbox chip inflight, the size of the debris required the entire gearbox to be replaced. In January 2014, an Osprey made a precautionary landing after another mid-flight gearbox chip, according to data obtained by The Associated Press.

Chipping can be caused by a variety of factors, including a lack of lubrication for the gears, or the gear teeth being subject to force overloads, said Rex Rivolo, a retired Air Force pilot who analyzed the Osprey for the Pentagon’s test and evaluation office from 1992 to 2007 as an analyst at the Institute for Defense Analyses.

The Osprey has a chip detector that triggers a warning to crews if metal fragments are detected, alerting them that there are pieces of metal breaking off the gears. “The procedure is to land immediately,” Rivolo said. “Most chip warning lights are due to very small pieces of metal and are harmless, and the aircraft lands safely.”

These are among the reasons why there was alarm this week over reports that Russia may be pursuing nuclear weapons in space.

The White House has said the danger isn’t imminent. But reports of the new anti-satellite weapon build on longstanding worries about space threats from Russia and China. So much of the country’s infrastructure is now dependent on U.S. satellite communications — and those satellites have become increasingly vulnerable.

It would also not be the first time a nuclear warhead has been detonated in space, or the only capability China and Russia are pursuing to disable or destroy a U.S. satellite.

Here’s a look at what’s happened in the past, why Russia may be pursuing a nuclear weapon for space now, and what the U.S. is doing about all the space threats it faces.

Starfish Prime, Project K

Both Russia and the U.S. have detonated nuclear warheads in space. In the 1960s, little was known about how the relatively new weapons of mass destruction would act in the Earth’s atmosphere. Both countries experimented to find out.

The Soviet tests were called Project K and took place from 1961 to 1962. The U.S. conducted 11 tests of its own, and the largest, and first successful, test was known as Starfish Prime, said Stephen Schwartz, a non-resident senior fellow at the Bulletin of Atomic Scientists.

Starfish Prime launched in July 1962, when the U.S. sent up a 1.4-megaton thermonuclear warhead on a Thor missile and detonated it about 250 miles (400 kilometers) above the Earth. The missile was launched about 800 miles (1,300 kilometers) from Hawaii but the effects from the tests were seen around the equator.

“The large amount of enerqy released at such a high altitude by the detonation caused widespread auroras throughout the Pacific,” according to a 1982 Department of Defense report on the tests.

The blast disabled several satellites, including a British one named Ariel, as radioactive particles from the burst came in contact with them. Radio systems and the electrical grid on Hawaii were temporarily knocked out, said Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists. The debris left satellites in its path malfunctioning “along the lines of the old Saturday matinee one-reeler,” the 1982 report said.

When the former Soviet Union conducted its own test as part of Project K, it did so at a slightly lower orbit and “fried systems on the ground, including underground cables and a power plant,” Kristensen said.

The U.S. and the Soviet Union signed a nuclear test ban treaty a year later, in 1963, which prohibited further testing of nuclear weapons in space.

White House national security spokesman John Kirby declined to say Thursday whether the emerging Russian weapon is nuclear capable, noting only that it would violate an international treaty that prohibits the deployment of “nuclear weapons or any other kinds of weapons of mass destruction” in orbit.

Satellite attacks today

It’s the ability to do that kind of damage that makes it logical that the Russians would want to put a warhead in space, especially if they see their military and economy weakened after fighting a U.S.-backed Ukraine for the past two years, said John Ferrari, a nonresident senior fellow at the American Enterprise Institute.

A space-based weapon that could cripple U.S. communications and the U.S. economy could be an intimidating equalizer, and would just be the latest development from both Russia’s and China’s efforts to weaponize space, he said.

In the past few years China has tested a satellite with a robotic arm that can maneuver to a system, grab it, and move it out of orbit.

Russia has developed a “nesting doll” satellite that opens up to reveal a smaller satellite, and then that one opens to reveal a projectile capable of destroying nearby satellites. In 2019, the Russians maneuvered a nesting doll near a U.S. satellite.

When one of those nesting doll systems “parks next to one of our high-value NRO capabilities, they are now holding that asset at risk,” the deputy chief of space operations of the U.S. Space Force, Lt. Gen. DeAnna Burt, said at a 2022 space conference. NRO is the National Reconnaissance Office.

Russia also generated headlines around the world when it conducted a more traditional anti-satellite test in 2021, where it shot down one of its own systems. As with the Starfish test, the impact created a large cloud of orbiting debris that even put the International Space Station at risk for awhile.

The new Space Force

The quickly evolving threat in space was one of the main drivers behind establishing the U.S. Space Force, Pentagon spokesman Maj. Gen. Pat Ryder said at a briefing Thursday. In the years since its 2019 creation, the service has focused on developing a curriculum to train its service members, called Guardians, on detecting threats from space and wargaming scenarios on what conflict in space would look like.

The creation of the Space Force elevated spending on satellite systems and defenses. Previously, when space needs were spread among the military services, spending on a new satellite would have to compete for funding with ships or fighter jets — and the services had a more immediate need for the aircraft and vessels, Ferrari said.

But there’s more work to be done, and the revelation that Russia may be pursuing a nuclear weapon for space raises critical questions for Congress and the Defense Department, Ferrari said. If Russia uses a nuclear weapon to take out satellites and that cripples the U.S. economy, does that justify the U.S. bombing Russian cities in return?

“How do you respond to that? You have no good option,” Ferrari said. “So now it’s a question of, ‘What is the deterrence theory for this?’ “

Those underground capsules are about to be demolished and the missile silos they control will be completely overhauled. A new nuclear missile is coming, a gigantic ICBM called the Sentinel. It’s the largest cultural shift in the land leg of the Air Force’s nuclear missile mission in 60 years.

But there are questions as to whether some of the Cold War-era aspects of the Minuteman missiles that the Sentinel will replace should be changed.

Making the silo-launched missile more modern, with complex software and 21st-century connectivity across a vast network, may also mean it’s more vulnerable. The Sentinel will need to be well protected from cyberattacks, while its technology will have to cope with frigid winter temperatures in the Western states where the silos are located.

The $96 billion Sentinel overhaul involves 450 silos across five states, their control centers, three nuclear missile bases and several other testing facilities. The project is so ambitious it has raised questions as to whether the Air Force can get it all done at once.

An overhaul is needed.

The silos lose power. Their 60-year old massive mechanical parts break down often. Air Force crews guard them using helicopters that can be traced back to the Vietnam War. Commanders hope the modernization of the Sentinel, and of the trucks, gear and living quarters, will help attract and retain young technology-minded service members who are now asked each day to find ways to keep a very old system running.

Nuclear modernization was delayed for years because the United States deferred spending on new missiles, bombers and submarines in order to support the post 9/11 wars overseas. Now everything is getting modernized at once. The Sentinel work is one leg of a larger, nuclear weapons enterprise-wide $750 billion overhaul that is replacing almost every component of U.S. nuclear defenses, including new stealth bombers, submarines and ICBMs in the country’s largest nuclear weapons program since the Manhattan Project.

For the Sentinel, silo work could be underway by lead contractor Northrop Grumman as soon as 2025. That is 80 years after the U.S. last used nuclear weapons in war, the bombs dropped on Hiroshima and Nagasaki in Japan, which killed an estimated 100,000 in an instant and likely tens of thousands more over time.

For the Pentagon, there are expectations the modern Sentinel will meet threats from rapidly evolving Chinese and Russian missile systems. The Sentinel is expected to stay in service through 2075, so designers are taking an approach that will make it easier to upgrade with new technologies in the coming years. But that’s not without risk.

“Sentinel is a software-intensive program with a compressed schedule,” the Government Accountability Office reported this summer. “Software development is a high risk due to its scale and complexity and unique requirements of the nuclear deterrence mission.”

Air Force Secretary Frank Kendall has acknowledged the challenges the program is facing.

“It’s been a long time since we did an ICBM,” Kendall said in November at a Center for New American Security event in Washington. It’s “the biggest thing, in some ways, that the Air Force has ever taken on.”

“Sentinel, I think quite honestly, is struggling a little bit,” he said.

New connections

By far, the biggest cultural shift the Sentinel will bring is the connectivity for all those who secure, maintain, operate and support the system. The overhaul touches almost everything, even including new equipment for military chefs who cook for the missile teams. The changes could improve efficiency and quality of life on the bases but may also create vulnerabilities that the analog Minuteman missiles have never faced.

Since the first silo-based Minuteman went on alert at Montana’s Malmstrom Air Force Base on Oct. 27, 1962 — the day Cuba shot down a U-2 spy plane at the height of the Cuban missile crisis — the missile has “talked” to its operators through thousands of miles of hard-wiring in cables buried underground.

Those Hardened Intersite Cable Systems, or HICS, cables carry messages back and forth from the missile to the missileer, who receives those messages through a relatively new part of the capsule — a firing control console called REACT, for Rapid Execution and Combat Targeting, that was installed in the mid-1990s.

It’s a closed communication loop, and a very secure one that brings its own headaches. Any time the Air Force wants to test one of the missiles, it literally has to dig up the cables and splice them, to isolate that test missile’s wiring from the rest. Over decades of testing, there are now hundreds of splices in those critical loops.

But it’s also one of the Minuteman’s best features. You would need a shovel — and a lot more — to try to hack the system. Even when missile crews update targeting codes, it is a mechanical, manual process.

Minuteman is “a very cyber-resilient platform,” said Col. Charles Clegg, the Sentinel system program manager.

Clegg said cybersecurity for the software-driven Sentinel has been a top focus of the program, one that has all of their attention.

“Like Minuteman, Sentinel will still operate within a closed network. However, to provide defense in depth, we will have additional security measures at the boundary and inside the network, enabling our weapon system to operate effectively in a cyber-contested environment,” Clegg said.

Frigid fields

Those who maintain the Minuteman III have tried over the years to bring in new technology to make maintenance more efficient, but they have found that sometimes the old manual way of tracking things — sometimes literally with a binder and pen — is better, especially in frigid temperatures.

Nuclear missile fields are located in Colorado, Montana, Nebraska, North Dakota and Wyoming. Those missiles need maintenance even in the winter, and crews spend hours outside in sub-zero field conditions,

“An iPad won’t survive a Montana winter” at the launch sites, where maintenance crews have worked outdoors in temperatures of minus 20 degrees or even minus 40 degrees, said Chief Master Sgt. Virgil Castro, the 741st missile maintenance squadron’s senior enlisted leader.

Also, when maintenance crews at Malmstrom tested some radio frequency identification, or RFID, technology — think of how seaports track items inside cargo containers — it created security vulnerabilities.

“Today, everything is connected to the internet of things. And you might have a back door in there you don’t even know” said Lt. Col. Todd Yehle, the 741st maintenance squadron commander. “With the old analog systems, you’re not hacking those systems.”

What it means is that even though technology could automate the whole operations process, one critical aspect of missile launch will remain the same. If the day comes that another nuclear weapon must be fired, it will still be teams of missileers validating the orders and activating a launch.

“It’s the human in the loop,” said Col. Johnny Galbert, commander of the 90th Missile Wing at F.E. Warren. “I think what it comes down to is we want to rely on our airmen, our young officers out there, to make that decision, to be able to interpret what higher headquarters is telling them or directing them to do.”

The Associated Press receives support for nuclear security coverage from the Carnegie Corporation of New York and Outrider Foundation. The AP is solely responsible for all content.

The Osprey takes off and lands like a helicopter but can tilt its propellers horizontally to fly like an airplane. That unique and complex design has allowed the Osprey to speed troops to the battlefield. The U.S. Marine Corps, which operates the vast majority of the hundreds of Ospreys in service, calls it a “game-changing assault support platform.”

But on Wednesday, the Air Force, Navy and Marine Corps grounded all Ospreys after a preliminary investigation of last week’s crash indicated that a materiel failure — that something went wrong with the aircraft — led to the deaths of all eight Air Force Special Operations Command airmen on board.

And it’s not the first time. There have been persistent questions about a mechanical problem with the clutch that has troubled the program for more than a decade. There also have been questions as to whether all parts of the Osprey have been manufactured according to safety specifications and, as those parts age, whether they remain strong enough to withstand the significant forces created by the Osprey’s unique structure and dynamics of tiltrotor flight.

The government of Japan, which is the only international partner flying the Osprey, had already grounded its aircraft after the Nov. 29 crash.

“It’s good they grounded the fleet,” said Rex Rivolo, a retired Air Force pilot who analyzed the Osprey for the Pentagon’s test and evaluation office from 1992 to 2007 as an analyst at the Institute for Defense Analyses, and who previously warned military officials that the aircraft wasn’t safe. “At this point, they had no choice.”

The Osprey has become a workhorse for the Marine Corps and Air Force Special Operations Command and was in the process of being adopted by the Navy to replace its C-2 Greyhound propeller planes, which transport personnel on and off at-sea aircraft carriers.

Marine Corps Ospreys also have been used to transport White House staff, press and security personnel accompanying the president. White House National Security Council spokesman John Kirby said they also are subject to the standdown.

While the Ospreys are grounded, Air Force Special Operations Command said it will work to mitigate the impact to operations, training and readiness. The command will continue to fly other aircraft and Osprey crews will continue to train on simulators, spokeswoman Lt. Col. Becky Heyse said.

It was not immediately clear how the other services will adapt their missions.

Questions about the clutch

The first Ospreys only became operational in 2007 after decades of testing. But more than 50 troops have died either flight testing the Osprey or conducting training flights over the program’s lifespan, including 20 deaths in four crashes over the past 20 months.

In July, the Marine Corps for the first time blamed one of the fatal Osprey crashes on a fleet-wide problem that has been known for years but for which there’s still no good fix. It’s known as hard clutch engagement, or HCE.

The Osprey’s two engines are linked by an interconnected drive shaft that runs inside the length of the wings. On each tip, by the engines, a component called a sprag clutch transfers torque, or power, from one proprotor to the other to make sure both rotors are spinning at the same speed. That keeps the Osprey’s flight in balance. If one of the two engines fails, the sprag clutch is also a safety feature: It will transfer power from the working side to the failing engine’s side to keep both rotors going.

But sprag clutches have also become a worrying element. As the Air Force, Navy and Marine Corps began looking at HCE events following incidents in 2022, they determined that the clutches may be wearing out faster than anticipated.

Since 2010, Osprey clutches have slipped at least 15 times. As the system re-engages, hard clutch engagement occurs. In just fractions of a second, an HCE event creates a power spike that surges power to the other engine, which can throw the Osprey into an uncontrolled roll or slide. A power spike can also destroy a sprag clutch, essentially severing the interconnected drive shaft. That could result in the complete loss of aircraft control with little or no time for the pilots to react and save their Osprey or crew, Rivolo said.

In the 2022 crash of a Marine Corps MV-22 in California that killed five Marines, hard clutch engagement created an “unrecoverable, catastrophic mechanical failure,” the investigation found. The fire was so intense it destroyed the Osprey’s flight data recorder — another issue the Marines have pushed to fix, by requiring new flight data recorders to be better able to survive a crash.

Ospreys have been grounded before

After Air Force Special Operations Command experienced two hard clutch engagement incidents within six weeks in 2022, the commander, Lt. Gen. James Slife, grounded all of its Ospreys for two weeks. An undisclosed number of Ospreys across the military were grounded again in February 2023 as work began on clutch replacements.

But getting replacements to all the aircraft at the time depended on their availability, Slife said in 2022.

And even that replacement may not be the fix. Neither the services nor defense contractors Bell Textron or Boeing, which jointly produce the Osprey, have found a root cause. The clutch “may be the manifestation of the problem,” but not the root cause, Slife said.

In last week’s crash, Japanese media outlet NHK reported that an eyewitness saw the Osprey inverted with an engine on fire before it went down in the sea. If eyewitness accounts are correct, Rivolo said, clutch failure and a catastrophic failure of the interconnected drive shaft should be investigated as a potential cause.

After its investigation of the 2022 crash, the Marine Corps made several recommendations, including designing a new quill assembly, which is a component that mitigates clutch slippage and hard clutch engagement, and requiring that all drivetrain component materiel be strengthened.

That work is ongoing, according to the V-22 Joint Program Office, which is responsible for the development and production of the aircraft. A new quill assembly design is being finalized and testing of a prototype should begin early next year, it said.

When asked what inspections the JPO will conduct on the fleet while they are grounded, the office told Military Times that’s still unknown.

“The mishap investigation will ensure a thorough look into the casual factors, which will help identify recommendations to address any issues uncovered,” Marcia Hart, a spokesperson for Naval Air Systems Command, said Thursday.

Whistleblower questions

Materiel strength was the subject of a whistleblower lawsuit that Boeing settled with the Justice Department in September for $8.1 million. Two former Boeing V-22 composites fabricators had come forward with allegations that Boeing was falsifying records certifying that it had performed the testing necessary to ensure it maintained uniform temperatures required to ensure the Osprey’s composite parts were strengthened according to DOD specifications.

A certain temperature was needed for uniform molecular bonding of the composite surface. Without that bond, “the components will contain resin voids, linear porosity, and other defects that are not visible to the eye; which compromise the strength and other characteristics of the material, and which can cause catastrophic structural failures,” the lawsuit alleged.

In its settlement, the Justice Department contended Boeing did not meet the Pentagon’s manufacturing standards from 2007 to 2018; the whistleblowers contended in their lawsuit that this affected more than 80 Ospreys that were delivered in that time frame.

In a statement to The Associated Press, Boeing said it entered into the settlement agreement with the Justice Department and Navy “to resolve certain False Claims Act allegations, without admission of liability.”

Boeing said while composites are used throughout the V-22, the parts that were questioned in the lawsuit were “all non-critical parts that do not implicate flight safety.”

“Boeing is in compliance with its curing processes for composite parts,” the company said. “Additionally, we would stress that the cause of the accident in Japan is currently unknown. We are standing by to provide any requested support.”

Ongoing fixes

The V-22 Joint Program Office said that since the 2022 incidents, significant progress has been made toward identifying the cause of the hard clutch engagement.

“While the definitive root cause has not yet been determined, the joint government and industry team has narrowed down the scope of the investigation to a leading theory,” it said in a statement to the AP. “The leading theory involves a partial engagement of some clutches which have been installed for a lengthy period of time. This has not yet been definitively proven, but the data acquired thus far support this theory.”

Bell assembles the Osprey in a partnership with Boeing in its facilities in Amarillo, Texas. Bell would not comment on last week’s crash, but said it works with the services when an accident occurs. “The level of support is determined by the service branch safety center in charge of the investigation,” Bell spokesman Jay Hernandez said.

In its report on the fatal 2022 crash, the Marine Corps forewarned that more accidents were possible because neither the military nor manufacturers have been able to isolate a root cause. It said future incidents were “impossible to prevent without improvements to flight control system software, drivetrain component material strength, and robust inspection requirements.”

Air Force Times Editor Rachel S. Cohen contributed to this story.

WASHINGTON — The military announced late Wednesday it was grounding all of its Osprey V-22 helicopters, one week after eight Air Force Special Operations Command service members died in a crash off the coast of Japan.

The Air Force, Navy and Marine Corps took the extraordinary step of grounding hundreds of aircraft after a preliminary investigation of last week’s crash indicated that a materiel failure — that something went wrong with the aircraft — and not a mistake by the crew led to the deaths.

The crash raised new questions about the safety of the Osprey, which has been involved in multiple fatal accidents over its relatively short time in service. Japan grounded its fleet of 14 Ospreys after the crash.

Lt. Gen. Tony Bauernfeind, head of Air Force Special Operations Command, directed the standdown “to mitigate risk while the investigation continues,” the command said in a statement. “Preliminary investigation information indicates a potential materiel failure caused the mishap, but the underlying cause of the failure is unknown at this time.”

In a separate notice, Naval Air Systems Command said it was grounding all Ospreys. The command is responsible for the Marine Corps and Navy variants of the aircraft.

The Air Force said it was unknown how long the aircraft would be grounded. It said the standdown was expected to remain in place until the investigation has determined the cause of the Japan crash and made recommendations to allow the fleet to return to operations.

The U.S.-made Osprey is a hybrid aircraft that takes off and lands like a helicopter but can rotate its propellers forward and cruise much faster, like an airplane, during flight.

Its unique design has been a factor in multiple incidents. While the investigation into last week’s crash has only just begun, it renewed attention on the aircraft’s safety record, particularly on a mechanical problem with the clutch that has troubled the program for more than a decade. There also have been questions as to whether all parts of the Osprey have been manufactured according to safety specifications.

In August, the Marines found that a fatal 2022 Osprey crash was caused by a clutch failure, but the root cause was still unknown. In its report on the crash, the Marines forewarned that future incidents “are impossible to prevent” without improvements to flight control system software, drivetrain component material strength, and robust inspection requirements.”

Air Force Special Operations Command has 51 Ospreys, the U.S. Marine Corps flies as many as 400 and U.S. Navy operates 27.

The Osprey is still a relatively young aircraft in the military’s fleet — the first Ospreys only became operational in 2007 after decades of testing. But more than 50 troops have died either flight testing the Osprey or conducting training flights in the aircraft, including 20 deaths in four crashes over the past 20 months.

An Osprey accident in August in Australia killed three Marines. That accident also is still under investigation.

The Raider flew in Palmdale, California, where it has been under testing and development by Northrop Grumman.

The Air Force is planning to build 100 of the warplanes, which have a flying wing shape much like their predecessor the B-2 Spirit but will incorporate advanced materials, propulsion and stealth technology to make them more survivable in a future conflict. The plane is planned to be produced in variants with and without pilots.

“The B-21 Raider is in flight testing,” Air Force spokeswoman Ann Stefanek said.

Such testing is a critical step in the campaign to provide “survivable, long-range, penetrating strike capabilities to deter aggression and strategic attacks against the United States, allies, and partners,” Stefanek said.

The B-21 Raider is the first new American bomber aircraft in more than 30 years, and almost every aspect of the program is classified. Both Northrop Grumman and the Air Force have tried to protect the program’s details to prevent China from gaining access to the weapon’s technology and building a similar version, as it has with other U.S. advanced weapons systems like the F-35 joint strike fighter.

The B-21 is part of the Pentagon’s efforts to modernize all three legs of its nuclear triad, which includes silo-launched nuclear ballistic missiles and submarine-launched warheads, as it invests in new weapons to meet China’s rapid military modernization.

Northrop Grumman Corp. is based in Falls Church, Virginia.