The Space Development Agency (SDA) is implementing an ambitious and complex strategy to counter the threats of hypersonic missiles—technologies currently being developed by America’s geopolitical rivals Russia and China.
The National Defense Space Architecture (NDSA) is a proposed multilayered network of small satellite constellations primarily in low Earth orbit. Each layer will have a specific role in the defense strategy and will be equipped with specialized satellites to perform its tasks.
Let’s take a closer look at how these different constellations will operate.
Transport Layer
This layer focuses on providing resilient and reliable military data and connectivity to U.S. forces around the world—from troops to F-35s to battlefield missile systems. The constellation will consist of 300 to 500 satellites; once deployed, 95 percent of them will have at least two other satellites in view and will communicate with each other via Optical Inter-Satellite Links (OISLs). This technology is capable of multi-gigabit-per-second data transfer speeds—and is more secure and resistant to interference than conventional radio frequency crosslinks.
The Transport Layer satellites will operate over the Ka band (frequency range from 27 to 40 GHz), have stereo coverage and be dynamically networked. The first batch of 20 satellites will likely have limited networking ability, but future enhancements and expansion are expected.
This layer will be the first to become operational—the Pentagon plans for dozens of units to be up and running by the end of fiscal year 2022, with hundreds in orbit by 2024 and global coverage by 2026. The satellites would have a five-year life span. Lockheed Martin was awarded a $187.5 million contract for the first 10 satellites, which would function as an initial testing and demonstration platform for the SDA’s concept.
Battle Management Layer
The Battle Management Command, Control and Communication Layer will be tasked with providing automated battle management intel for space-based conflicts. These include space-based command and control, military asset deployment, and mission management and processing. In-orbit updates to flight software will ensure the system has the latest threat information.
Custody Layer
The Custody Layer is responsible for monitoring enemy “left-of-launch” activities—that is, everything that happens before the weapon is fired. This layer will provide round-the-clock time-sensitive surveillance, in any kind of weather, of surface mobile targets that are associated with hypersonic weapons launches. The constellation will use that data to formulate targeting options—which will then be fed to other military assets automatically, conceivably resulting in real-time targeting information for U.S. forces closer to the ground. The layer will rely on sophisticated algorithms that would adapt to rapidly evolving situations and derive information from a variety of sensors.
Tracking Layer
One the weapon is fired—or “right of launch”—the Tracking Layer kicks in. This constellation will be responsible for identifying, tracking and targeting the movements of hypersonic weapons.
The Pentagon recently awarded contracts to SpaceX and L3Harris to develop military satellites for the layer. Each company will build four satellites equipped with a wide field of view (WFOV) infrared sensor called an overhead persistent infrared (OPIR) sensor. SpaceX will base its technology on its Starlink constellation, while L3Harris has not made any details public.
Emerging Capabilities (Deterrence) Layer
Perhaps the most science-fictional component of this ambitious project, this group of satellites will be tasked with responding to threats from deep space—beyond geosynchronous orbit and extending as far as the moon. This layer will also serve as an incubator for conceptualizing, assessing and developing new concepts, technologies and missions that the other layers don’t cover.
Interestingly, one of the ideas the Pentagon will explore for this layer is a advanced maneuvering vehicle “with sufficient kinematic capability to quickly reach areas of interest in the deep space regime”—which sounds like a hypersonic weapon itself.
Navigation Layer
Should the GPS capabilities of American forces be denied or compromised by an enemy, the Navigation Layer would step in to provide alternative navigation, positioning and timing. It would work to predict orbits and trajectories of adversarial technologies—possibly including satellites and missiles. The layer also contains a cybersecurity component, as the U.S. military will be working on cryptographic systems to protect GPS-related integrity, confidentiality and reliability.
Support Layer
This final layer brings in ground infrastructure and launch systems to help keep the other layers functioning properly. This layer will manage the whole NDSA satellite constellation: hosting, managing and executing tactical command and control functions, mission processing, and ground-based communications gateways; implementing cybersecurity components; and providing computing, networking and storage. This infrastructure will also need to be adaptable enough to be deployed to satellite operations centers around the world. And finally, the layer will need to coordinate launches, integrate new satellites into the constellation, and facilitate human operator training. Think of it as the NDSA’s IT department.
A New Approach to Satellite Design, Production and Deployment
The NDSA represents a dramatic strategic shift away from traditional military satellites, which tend to be large, multipurpose spacecraft. These satellites may be able to detect and follow a Cold War-era nuclear missile—but don’t have the responsiveness required to track a hypersonic vehicle that could be traveling at Mach 5 or faster.
In contrast, a large, distributed network of small, specialized satellites—and lots of them—could be better able to respond to an anti-satellite attack or hypersonic weapon launch than existing early warning systems. It could be harder for enemy anti-satellite weaponry to take out so many smaller targets than it would be to take out a few bigger assets: the constellation will be able to retain most if not all of its functionality should some of its units be compromised. Small satellites can be built faster and cheaper—and new units can be launched to replace damaged or destroyed satellites more quickly.
The SDA is also working more closely with commercial entities than is typically found in government—leveraging the private sector’s innovation and manufacturing know-how to rapidly develop, produce and deploy the satellites. “We as an agency accept a higher level of risk, employ novel business models, and move to develop and field capabilities more quickly than you might see in ‘traditional’ government agencies,” the SDA said.
Emerging hypersonic threats could mean that space might become a new conflict zone—and the Pentagon’s innovative strategy will undoubtedly have a significant influence in what happens in that new arena. “Space is a strategic domain and the United States must maintain peace through strength in space,” said the Department of Defense.
Read more about hypersonic weapons technologies at Will Hypersonic Weapons Mean a New Arms Race?