A US Navy attack submarine enters Apra Harbor in Guam.

THE FUTURE: Imagine you’re a Chinese high commander, taking stock at the outbreak of the next great war. All your aides and computer displays tell you the same thing: For hundreds of miles out into the Western Pacific, the sea and sky are yours. They are covered by the overlapping threat zones of your long-range land-based missiles, your Russian-made Sukhoi aircraft, your home-grown stealth fighters, and your ultra-quiet diesel submarines, all cued by your surveillance network of sensors on land, sea, air, and space.

The net effect is what the West calls Anti-Access/Area Denial (A2/AD)  and you call counter-intervention. Now you can deal with the Japanese imperialists and Taiwanese separatists without American interference. As Mao’s followers once sang, the East is Red.

Then it all starts rotting from the inside out.

Here and there, in patches, your sensor coverage goes fuzzy, communications become erratic: American jamming. But the interference isn’t at the periphery of the defense zone, where US sea, land, and air forces are slamming away from the outside. It’s emerging close to the Chinese coast. The source can only be American submarines.

Chinese aircraft scrambled to stop the jamming find antennas on buoys, unmanned boats, or small drones. Each one is easily destroyed, but there are a lot of them. For each one you wipe from your screens, another two pop up. Meanwhile the American submarines themselves remain elusive, silently dropping expendable, unmanned jammers that wait for the sub to get well away before they go active. When your sub-hunters do find something underwater, it’s usually an unmanned submersible or a weapons pod lying on the seafloor.

At least part of the problem is inside your network, too. Radars and radios are failing in places out of range of any jammer. Some submarine-launched system must have hacked into your wireless transmissions and injected a virus.

And now, only now, as your forces start going deaf and blind, do the Americans mount a physical attack. American Air Force bombers, Navy warships, and Army artillery batteries start firing cruise missiles through the gaps in your sensor coverage. In some places, F-35 stealth fighters slip past your struggling radars; in others, EA-18G Growler aircraft pour on high-powered jamming. Each strike tears another node from your network. You can still see and communicate well enough to know the attacks are coming, but not well enough to stop them.

Cruise missiles are rising from your own home waters now. The submarines off China’s coast have grown so confident that they’ll risk revealing their positions to fire. Or perhaps it’s more of those autonomous weapons pods on the seafloor. You don’t have the sensors left to figure out which.

Any of these incoming weapons could have a nuclear warhead aimed at Beijing. There’s no way to tell and no way to stop them all. This can’t go on.

Knowing it will cost your career, or worse, you pick up the hardened landline phone. “Comrade Chairman,” you say, “I advise that we seek a ceasefire.”

Vice Adm. Michael Connor

War For The Spectrum

“To control the electromagnetic spectrum, you have to be able to put whatever your device is that controls that spectrum in the place where you need it,” declared Vice Adm. Mike Connor, commander of Atlantic submarine forces, in address to the Naval Submarine League. In the submarine force, he went on, “we have a remarkable ability to take the sensors that we have” — as well as “offensive” systems, he added — “and put them in the place they are most relevant, because we can get closer.”

“We’re the ultimate stealth force,” Connor told me when I approached him after his talk. “We can knock down some of that A2/AD defense. We can tell someone we’ve done that” — that is, by reporting back to the main fleet — “[and] start telling them where things are, and then we can start working with them to coordinate the next wave.”

There’s a danger here, Connor acknowledged. Submarines survive by hiding: They emit as little as possible, whether it’s sound waves or electromagnetic ones. They risk revealing their position every time they transmit reports to other units, let alone if they turn on a jammer. Whether that risk is worth it will be a crucial decision for the future submarine commander

“He’s going to have to go, ‘Hey, is it time to give up stealth to go tell someone what’s going on?'” said Connor. “He’s going to have to decide that and I can’t decide that from Norfolk, Virginia.”

But it’s not a binary either/or, on/off. How long you transmit, how strongly, where and when are all variables the commander can adjust to set the balance of gain and risk — part of what the Navy calls Electromagnetic Maneuver Warfare. Another aspect, Connor told me, is “sending some payload way over there and having them tell [the rest of the fleet]. There’s a lot of stuff you can do like that.”

What the admiral is hinting at is using submarines to launch unmanned systems. These could be as simple as a communications buoy that rises to the surface, waits a set time, and transmits. They could be expendable drones, launched from a submarine’s missile tubes the same way as a Tomahawk. They could be complex mini-subs in themselves, known as large diameter underwater unmanned vehicles (LDUUVs), that can launch from a manned sub to conduct a long-range mission. They could even be large payload modules that are towed behind a submarine until, at a strategic point, it releases them to settle to the sea floor and await the signal to unleash their payload of UUVs, drones or missiles.

Whatever form they take, the robots have the same essential purpose: to keep the expensive and precious manned submarine at a distance from danger by sending an unmanned surrogate instead. Even a large-diameter UUV or seafloor-lurking pod is a fraction the size of a sub, with no nuclear reactor or human beings onboard, so it’s much harder to find and hit. Even if it is destroyed, its loss is much more acceptable than that of a $2-plus billion sub with 132 souls aboard.

That makes unmanned vehicles the logical choice for electronic warfare. Jamming means transmitting in a way the enemy can pick up, so a jammer by definition reveals its presence (though it may be hard for the enemy to lock onto and shoot). A single jammer can launch multiple EW drones and have them wait a while, fly a ways, or both before they go active and blaze their presence across the enemy’s screens.

EW also encompasses subtler missions, however. Indeed, electronic warfare, cyber warfare and espionage are increasingly blurring together.

Underwater Espionage

Submarines have long served as spies. The US tapped underwater cables during the Cold War. But underwater espionage “really expanded with the introduction of things like Wi-Fi,” said Bryan Clark, a retired Navy submariner now with the Center for Strategic & Budgetary Assessments. Just like your neighbor who forgot to put a password on her home’s wireless network, he said, governments aren’t always as careful as they should be.

But how to tap this modern source of intelligence? “You can be out beyond the territorial [waters] of a country and you can pick up wireless signals, [but] if you drive around there with a surface boat, people are going to see you and wonder what the heck you’re doing,” Clark said. “Submarines offered this opportunity to get in close.”

“It started in the Cold War [and] really picked up in the late ’90s, early 2000s, and now that’s a pretty significant mission for the submarine force,” Clark said. “SIGINT [Signals Intelligence] and electronic warfare end up being really good missions for a submarine, because they don’t require a huge amount of payload but they do require access, [stealth], and persistence.”

But submarines do have real limits as electronic eavesdroppers. “The mast doesn’t stick that far out of the water,” Clark said, “[so] your horizon’s pretty close, so you can’t get too far away.” The periscope mast can also only carry a relatively small sensor — although Navy upgrade programs are making the best they can of limited space — which limits range still more. US submariners have been able to work around these problems, Clark said, “[but] against an alerted enemy, getting close enough to really get a good signal is hard.”

It’s only going to get harder, added another CSBA scholar, Robert Martinage. “Adversaries are getting better for a host of reasons, largely technology-driven, at anti-submarine warfare,” he told me, “so getting in real close in shallow waters to do that type of mission may be increasingly problematic for the large manned submarines in the future.”

“That’s why we want to offboard that mission to UUVs,” Martinage said, with the manned sub hanging back as the mothership. That’s not a simple solution, he emphasized. “The two long poles technologically with UUVs are one, autonomy” — that is, the robot’s ability to make decisions for itself — “and the second is high-density energy storage so you can have both endurance and speed underwater.” Currently, he said, you can have a long-range unmanned underwater vehicle or a fast one, but not both.

The other alternative is Unmanned Aerial Vehicles. As strange as launching aircraft from underwater may seem, there’ve been successful experiments doing exactly that, for example with a folding-wing mini-drone called Sea Robin. You can’t fit a large, long-range drone on a submarine — the Navy’s MQ-4C Triton, for example, has a wingspan of 131 feet — but you can get close enough that a short-ranged one is viable, Clark said.

The downside to carrying UAVs and UUVs is they displace missiles and torpedoes, and submarines are always tight on space. But Clark and Martinage argue that carrying unmanned systems to spy on, jam, and hack enemy electronics is a better use of a sub’s limited payload than kinetic weapons.

“You’re better off using the submarine to deliver smaller electronic warfare payloads, [because] they’re smaller than the missiles, so you can carry them in larger numbers,” Clark told me. That means the sub can keep doing the electronic/cyber warfare mission longer than it can keep up a kinetic bombardment. What’s more, he argued, even a submarine maxed out on missiles may not do much against a sophisticated foe. We can hit targets with Tomahawks at will in Third World countries, “[but] as defenses get better, three or four cruise missiles aren’t going to be enough,” he said, “[and] if I’m launching a dozen cruise missiles, that’s like the whole capacity of a Virginia-class submarine.”

The upgrade known as the Virginia Payload Module will more than triple the number of launch tubes on future Virginias. You could fit even more weapons on a towed payload module, external to the submarine, that could be deposited on the ocean floor and commanded by remote control, Martinage argued. But even with this extra capacity, he agrees that jammers and sensors will often be a better use of payload space than explosive warheads.

“Submarines…need to take on a wider variety of missions beyond just anti-surface warfare or anti-submarine warfare or even land attack,” Martinage told me. “There are lots of other ways in the joint force to do standoff land attack,” he said, from surface ships with Tomahawks to long-range bombers, “but there aren’t as many ways to get in close under an adversary’s A2/AD umbrella and do other missions.”