27-05-2025
Uncertainty Over AN/TPY-6 Guam Missile Defense Radar Emerges
In January, the U.S. military moved to halt work on the new AN/TPY-6 radar, one of seven key elements of the huge new air and missile defense architecture taking shape on Guam, and its current status is now unclear. This underscores other important, but still unanswered questions about the plans to better protect the extremely strategic U.S. island territory in the Western Pacific, including the total personnel required and which services they will come from.
In a memo to the Missile Defense Agency (MDA) on January 7, then-U.S. Deputy Secretary of Defense Kathleen Hicks directed the termination of all further development of AN/TPY-6, according to a report the Government Accountability Office (GAO), a Congressional watchdog, published last week. Hicks left the post President Donald Trump took office later that month, being succeeded first by Robert Salesses (in an acting capacity) and then by Stephen Feinberg.
At least as of December 2024, what is currently being called the Guam Defense System (GDS) was expected to eventually consist of seven core components. In addition to the AN/TPY-6, these included: an array of ground-based missile launchers based on the Mk 41 Vertical Launch System (VLS), SM-3 and SM-6 interceptors to go in those launchers, Mk 99 fire control systems (which includes AN/SPG-62 radar 'illuminators'), a Guam-specific version of the Aegis Ashore command and control system (the Aegis Guam System), and the Guam Command Center (GCC) facility. A single prototype AN/TPY-6, a Lockheed Martin design derived from that company's AN/SPY-7 Long-Range Discrimination Radar (LRDR) in Alaska. Other components, including smaller radars and shorter-range interceptors, could also be part of the final GDS configuration.
However, 'other than system experimentation efforts, further development of the AN/TPY-6 radar shall be terminated,' Hicks' memo said, per GAO's report. 'The MDA shall prioritize remaining Aegis Guam System development funds toward delivering minimum viable Aegis C2 [command and control] and datalink capabilities to enable Standard Missile 6 (SM-6) engagements off remote tracks from AN/TPY-2 and LTAMDS over the JTMC [Joint Track Management Capability] bridge.'
The AN/TPY-2 is an existing ground-based air and missile defense radar primarily associated with the U.S. Army's Terminal High Altitude Area Defense (THAAD) anti-ballistic missile defense system, but that can also be used as a stand-alone sensor. The LTAMDS (Lower Tier Air and Missile Defense Sensor) is a new radar that the Army is working to field now, primarily as an upgrade for the Patriot surface-to-air missile system.
'The Joint Track Management Capability (JTMC) bridge' refers to command and control upgrades intended 'to address the full set of PRC [People's Republic of China] missile threats to Guam and to achieve a Joint Tactical Integrated Fire Control (JTIFC) capability for coordinated battle management, combat identification, and electronic protection,' the GAO report said, also citing Hicks' January memo.
Hicks also called on MDA to 'retain the single AN/TPY-6 panel currently on-island, with all associated flight test equipment, and maintain it in its current form as an experimental asset, with potential to develop for operational use within the GDS architecture in the future,' according to GAO.
GAO's report does note that 'a DOD official told us these changes in the then-deputy secretary's classified memorandum are not binding on the new administration,' but does not say whether or not Hicks' directive with regard to the AN/TPY-6 was subsequently reversed. No further details about what may have prompted the move to terminate work on the radar are provided, which does not appear to have been previously disclosed. The AN/TPY-6 was used, without any reported issues, during the GDS' first live intercept of a surrogate ballistic missile last December. That test also marked the first time the radar had supported an end-to-end live-fire engagement.
TWZ has reached out to the Office of the Secretary of Defense, MDA, and Lockheed Martin for more information about the current status of the AN/TPY-6.
Even if the immediate decision to axe the AN/TPY-6 as part of the GDS has been reversed, the fact that the U.S. military had moved to cancel it still raises questions about its future and the broader plans for vastly expanding air and missile defenses on Guam. The overall focus of GAO's recently published report was to highlight serious ongoing uncertainty around personnel and other infrastructure requirements for the new defensive architecture, which is set to make the skies over and around the U.S. island territory some of the most heavily defended airspace on Earth.
'DOD has established organizations to manage the deployment of GDS and designated lead services for sustainment and operations,' GAO's report noted.
'However, DOD lacks a strategy to transfer responsibilities to their lead organizations. As a result, DOD risks schedule delays for the deployment of GDS elements and incomplete plans for organization, training, personnel levels, and facilities, among other things,' according to GAO. 'Moreover, although the Army officially joined JRM [the Joint Region Marianas] in February 2024, the Army has not identified its long-term strategy to advocate for construction priorities and installation support from the other military services. Without a strategy, the Army may continue to face delays in approval of construction projects and risks deploying additional personnel without installation support services in place.'
MDA has projected in the past that the 805 personnel will be needed to support GDS by 2027, and that the figure will grow to 1,044 by 2031, but 'senior military officials told us the draft statement is just a benchmark for the military services, because the services still need to validate and fund those requirements,' per GAO. 'Since planning for GDS began in fiscal year 2022, DOD has not fully identified the required number of personnel or completed a deployment schedule for GDS units.'
GAO said disputes between the Army and Navy over roles and responsibilities for certain components of the GDS that were resolved late last year had been a factor. The table below shows the lead entities that have been in charge of developing each of the system's seven core components, as well as Army recommendations for managing the operation and sustainment of those elements in 2023, and the final decisions that then-Deputy Secretary of Defense Hicks made in November 2024.
All of this has cascading impacts on work to build new infrastructure to support the GDS. The recently published GAO report also highlighted the still seriously limited infrastructure currently available to the Army's Task Force Talon on Guam, which operates and maintains a THAAD battery on the island now, despite those forces having been in place since 2013.
As it stands now, GAO says the goal is for the first elements of the GDS to be deployed by Fiscal Year 2027, which aligns with previous statements from U.S. officials, and the complete system is scheduled to be in place by Fiscal Year 2032. Any significant delays to that timeline could have larger ramifications.
Since 2021, expanding air and missile defenses on Guam has been a centerpiece of larger U.S. military efforts to reorient itself to preparing for future large-scale conflicts, especially a potential high-end fight with China in the Pacific. Guam is a vital hub for U.S. air and naval operations in the Western Pacific. It is also an important location for staging ground forces for onward movement across the region. In turn, being able to adequately protect key facilities on the island, including Andersen Air Force Base, Naval Base Guam, and Marine Corps Base Camp Blaz, especially from a growing array of Chinese ballistic, cruise, and hypersonic threats, is seen as critical. Various tiers of drones are also a real and still evolving threat. Guam could be a target for other adversaries, as well. Concerns about increasingly longer-range North Korean ballistic missiles prompted Task Force Talon's initial deployment more than a decade ago.
The GDS plans also reflect the U.S. military's persistent preference to focus on expanding active air and missile defenses, together with new distributed concepts of operations, over improved passive defenses, such as building new hardened aircraft shelters. Critics, including members of Congress, have been increasingly warning that not investing in additional hardened infrastructure puts American forces at significant risk, particularly if a high-end conflict in the Pacific with China were to break out. U.S. officials have made clear that they do expect to have to fight from places like Guam while under attack in any such scenario. You can read more about this heated debate, which TWZ has been following closely, here.
Whatever the fate of AN/TPY-6 radar might be now, the U.S. military still clearly has significant work to do in finalizing its plans for ensuring Guam is as shielded as possible from growing air and missile threats.
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