Pentagon contemplating eventual sunsetting of Link 16 as enthusiasm grows for optical communications

NATIONAL HARBOR, Md. — Discussions about the eventual phaseout of Link 16 tactical data links are ongoing as the Pentagon’s Space Development Agency works to build out a network for optical communications, according to a senior official involved in the effort.

Optical comms networks use lasers to transmit data between satellites and from space vehicles to terrestrial platforms. These capabilities offer some advantages over RF networks, experts say.

“As space becomes increasingly contested and congested, traditional radio frequency communications are hitting some limits. We’re facing bandwidth constraints, security vulnerabilities, plus growing susceptibility to jamming, interference. Meanwhile, our adversaries are rapidly advancing their own space-based capabilities, making secure, high-speed data transfer more critical than ever. And this goes beyond space. The collaborative, real-time partnering attributes we’ll need in the terrestrial domains will rely on connectivity — and laser comms will be a big part of that equation. It offers a crucial pathway forward promising higher data throughput, lower latency and inherent resistance to interception,” Jennifer Reeves, senior resident fellow for space studies at the Mitchell Institute, said Wednesday during a panel at AFA’s Air, Space and Cyber conference.

The Space Development Agency is building out an optical ground network, according to Nathan Getz, director of SDA’s data communications cell.

“We will use that network for our own purposes to backhaul data. We call those ground entry points. … We’re building out a network of those. We also have a number of test sites, and we used those in some recent demonstrations,” he said during the panel. “We use them so that we can opportunistically connect with satellites. And then we’re also working with the warfighter community to develop what we call tactical optical sites and those capabilities. So, kind of three classes of optical terminals. We’re excited because we see optical comms at an inflection point, and we see it start to scale up and start getting economies of scale. So … we’re excited about the scale that’s coming, and we’re trying to be very adaptive to that.”

SDA is creating what the Defense Department calls a Proliferated Warfighter Space Architecture, which is expected to eventually include hundreds of satellites in low-Earth orbit for data transport as well as missile tracking.

The data transport layer of the PWSA is seen as the backbone of the Pentagon’s warfighting construct dubbed Combined Joint All-Domain Command and Control (CJADC2), which aims to connect the many sensors, shooters and data streams of the U.S. military services, allies and partners under a more unified network.

“We’re heading into a world where, for the first time, we have lots of proliferated low-Earth orbit satellites with sensors on them. So, what that means is we’re going to have an unprecedented amount of data coming down and available to us. So, optical communications is … very fortuitous. It’s a linchpin for this new capability that we have and this new kind of world that we’re heading into with constant sensors … thousands of sensors up there constantly generating data, and we need ways of shuttling that data around — whether that’s from between satellites, or getting them from the space layer down to terrestrial targets,” Getz said.

Laser comms can also enable adaptability and new concepts of operation, he noted.

“We need the ability to replan and be very flexible in our kill chains, in our kill webs. We need that capability. And with optical communications, we can now shuttle data around to different places and are better able to support dynamic operations,” Getz said.

“Another thing with making optical communications scaled up and ubiquitous is that when the marginal cost of moving data around goes to zero … every node in a network, whether that’s in space or on the ground, can now learn from the other. So it’s kind of like a compound learning effect. And so I’m speaking abstractly, but these translate into very real ConOps. And so we’re very excited about all those changes that can take place in the way we operate,” he added.

As emerging technologies such as laser comms are scaled up, defense officials are contemplating the eventual sunsetting of Link 16, which is widely used across the military, Getz noted.

He envisions a future where the Defense Department — which the Trump administration recently rebranded as the Department of War — has a mix of optical communications and RF networks.

“We’re always gonna have RF … [but] we’re merging into scaled-up optical comms,” he said. “Link 16 is, I believe, the largest Department of War tactical network in existence … so in terms of breadth and depth of reaching your forces, it’s very much still relevant. It’s also used by a lot of our allies. … So, that community has a lot of inertia. That being said, I think it is also fair to talk about what comes next and, you know, do we sunset Link 16? And I think the answers to those are yes. You know, we can debate the time frame, but Link 16, while valuable, you know, someday will sunset. And those discussions are happening.”

In the meantime, SDA is making sure its architectures work with legacy comms tech as the agency puts the initial tranches of PWSA satellites into orbit.

“In the near term, with our tranche one, tranche two, we are definitely building out a … global Link 16 network, where we can connect Link 16 nets terrestrially with any point on the Earth, and that’s going to be very valuable. But there will be new technologies that come and supplement it and then eventually replace it,” Getz said.

However, he reiterated that he doesn’t expect the growth of optical comms to lead to the department moving completely away from RF for tactical networks.

Laser communications technology still faces significant challenges, Reeves noted, such as atmospheric interference and the complexity of establishing precise links between fast-moving satellites.

A Government Accountability Office report released earlier this year said SDA hadn’t fully proven out on-orbit laser communications. On Wednesday, Getz said the agency has been “working through those” issues and the effort is “picking up speed,” noting successes from various demonstrations.

As far as sunsetting Link 16, that won’t happen in the very near term, Getz told DefenseScoop.

“Certainly not in the next couple years when we’re building out tranche one and tranche two, and that is going to be … Link 16,” he said. “This is more longer term.”

The agency deployed the first batch of operational data transport satellites for the PWSA earlier this month, as part of tranche one.

SDA plans to launch new tranches every two years or so.

“Tranche three is very much in play right now,” Getz told DefenseScoop when asked about the future sunsetting of Link 16.

However, he noted that such a decision isn’t up to SDA alone because there are many stakeholders across the Defense Department.

“We’re certainly relevant because we’re building a global Link 16 capability. But there’s a lot of players here,” Getz said. “Look at the Link 16 user community. That size kind of tells you something. There is a certain amount of inertia that happens because of that. You know there are better ways to comm — I mean, you can get higher throughput with optical, for example — but … it’s deployed everywhere.”