The Indo-Pacific region is vast. The range, speed, and number of advanced weapons, both manned and unmanned, are increasing. U.S. and allied infrastructure are already within the so-called threat rings of potential adversaries’ offensive systems. To cover the environment and deal with growing threats, U.S. air and missile defenses will need increased sensing capabilities spread over a wide area, from the Western Pacific to the Contiguous United States (CONUS). An architecture based on a set of relocatable land and sea-based radars would allow for enhanced data collection against all threats, including hypersonic ballistic and cruise missiles. More broadly, distributed sensor nodes also enhance the overall resilience of the defensive architectures and reduce the chances an adversary can blind the defense by attacking a small number of critical sites.
Chinese—and to a lesser extent North Korean—missile programs pose a serious and growing threat to U.S. forward deployed forces and infrastructure, close allies, and even CONUS. China fields a large and sophisticated arsenal of short, medium, and long-range dual-capable ballistic and cruise missiles, some with precision guidance. Beijing is also racing ahead to develop hypersonic weapons that could reduce the effectiveness of traditional air and missile defenses. A recent RAND Corporation study of the Chinese missile threat just to U.S. and allied air bases in the Indo-Pacific region concluded that “in a conflict, these capabilities will challenge the ability of the U.S. to operate safely or efficiently from forward air bases and would have major spillover effects on other parts of the battle.”
The North Korean missile threat to the homeland is becoming increasingly sophisticated. Pyongyang, which can already target Hawaii and Alaska, is on the threshold of fielding a ballistic missile with sufficient range to reach the lower 48 states. It has announced its intentions to develop hypersonic glide bodies to fly aboard its longer-range missiles.
To be clear, the U.S. has added to its vulnerability to missile attacks by becoming dependent on a small set of extremely valuable ports and airfields. The U.S. military in the Indo-Pacific is working hard to alter its basing posture, operating concepts, and logistics systems to be less dependent on large, fixed infrastructure. Even if these efforts are successful, the reality is that some locations, such as Guam, will remain vital to the operation.
Considering both the Chinese and the North Korean missile threats, there is a growing need for more robust U.S. air and missile defense in the region. Sensing is the key to defending against missile threats to both forward positions in the Indo-Pacific and CONUS. Recently, Air Force General John Hyten, vice chairman of the Joint Chiefs of Staff, candidly observed that “the common thread for all missile defense systems is, can I see the threat, can I see the threat coming at me? The big piece is not shooters but sensors.”
The traditional approach to sensing relies on a relatively small number of large fixed radars focused on well-established threat corridors. This is particularly the case with respect to the defense of CONUS. Given their location, the ability of these sensors to see low-flying threats such as a hypersonic glide vehicle is limited by the curvature of the earth. In addition, because they are generally located far apart, there are seams in coverage that a smart attacker could exploit.
The sheer number of potential ballistic and cruise missiles that will be launched against U.S. and allied targets in the event of a high-end conflict and the introduction of hypersonic weapons suggest a new approach to creating a missile defense sensor architecture needed. An alternative approach is one focused on distributed sensor capabilities, primarily radars, across the region and in CONUS. This distributed sensing model is based on the proliferation of smaller, relocatable land and sea-based radars, supplementing existing radars to significantly improve the ability of the overall sensor grid to see and track incoming threats.
A distributed sensor network offers a number of advantages over the current architecture. By deploying multiple radars on land and sea, including in forward positions, the defense can improve its coverage against low-flying and maneuvering threats. Multiple smaller relocatable radars and sea-based radars improve coverage against low-altitude threats. New viewing geometries can be established that can improve the overall system’s ability to track and discriminate warheads. With more radars, the energy of each can be focused on a smaller cone, improving the chance of detecting incoming warheads. The defense can also operate some radars in a passive mode, allowing them to receive the energy from their active counterparts while being less vulnerable to detection and attack.
Perhaps most importantly, a distributed sensor architecture will degrade more gracefully under attack than the traditional system with its limited number of high-value nodes. Also, it would be easier to take some of these smaller radars offline for maintenance which otherwise would create significant gaps in sensor coverage.
A distributed architecture would be particularly useful in the Indo-Pacific theater. The U.S. military is already planning to distribute its forces widely among the waters and islands of the Western Pacific. By proliferating forward deployed, relocatable land and sea-based radars, the U.S. military can significantly improve its ability to deal with the massive Chinese air and missile threat. This distributed architecture can be tied into existing fixed U.S. and allied radars and C2 networks.
A distributed system would make particular sense for the defense of Guam, which will be a primary target for Chinese and North Korean missiles. By deploying multiple radars, the integrated system’s overall range, coverage and sensitivity would increase. This would allow it to deal with large and sophisticated attacks. Multiple radars mean that the effect of any one or two being struck on the ability to conduct air and missile defense of the island is reduced. By networking these sensors, the defense could engage in electronic protection measures while it was conducting air and missile defense operations. Additional ship-based radars could be added for increased effectiveness and resilience.
The U.S. military has decided that the key to success in high-end operations in the Indo-Pacific theater is distributed operations on land and sea. Creating a distributed radar network in this region should be part of this realignment of U.S. forces and concepts of operations.
Dan Gouré, Ph.D., is a vice president at the public-policy research think tank Lexington Institute. Gouré has a background in the public sector and U.S. federal government, most recently serving as a member of the 2001 Department of Defense Transition Team. You can follow him on Twitter at @dgoure and the Lexington Institute @LexNextDC. Read his full bio here.