GAO: US Navy’s Zumwalt hypersonic missile upgrade program hit by major delay

July 20, 2026, by Fatima Bahtić

The US Navy’s effort to equip its three Zumwalt-class destroyers with the conventional prompt strike (CPS) hypersonic missile has fallen 24 months behind schedule, according to a new report from the US Government Accountability Office (GAO), raising fresh concerns over the timeline for fielding the navy’s next-generation long-range strike capability.

The report, published on July 17, found that the Navy’s modernization program for the DDG 1000 class continues to face technical and programmatic challenges, while the CPS missile itself has encountered funding, testing, quality, and production issues that have delayed the overall effort.

According to GAO, modernization of the lead ship, USS Zumwalt (DDG 1000), was 94% complete as of January 2026, but remains behind schedule because of unplanned work. The overhaul includes replacing the destroyer’s original gun systems with an advanced payload module capable of launching CPS hypersonic missiles, transforming the vessel into a long-range surface strike platform.

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Vessels

The watchdog noted that flight testing of the CPS weapon from a Zumwalt-class destroyer was originally scheduled for 2025 but has now slipped to 2027, citing funding constraints and testing challenges.

Beyond the modernization work, GAO highlighted long-term sustainment concerns for the DDG 1000 class, noting that the ships’ unique radar, combat, and networking systems make them expensive and difficult to maintain.

The report also identified problems within the CPS program itself. Quality control and manufacturing issues have reduced missile production well below the planned rate of 12 rounds annually, potentially affecting future deployment schedules.

The Navy plans to field CPS aboard all three Zumwalt-class destroyers before expanding the capability to selected Virginia-class attack submarines. The hypersonic weapon is intended to provide the service with the ability to strike high-value, heavily defended targets from long range using a conventional, non-nuclear payload.

GAO also examined how the Department of Defense is managing the broader CPS enterprise, which includes the Navy’s program, the Army’s Long-Range Hypersonic Weapon, and Virginia-class submarine integration. Collectively, these efforts represent an investment of more than $50 billion.

While Army and Navy officials coordinate on day-to-day activities, GAO found that the two services continue to make major investment decisions independently, limiting opportunities to improve efficiency across their shared missile production infrastructure.

“DOD does not have a comprehensive strategy across all programs that ensures that each program’s investments achieve CPS’s common objectives. Without a comprehensive investment strategy that includes more formal coordination, the Army and Navy are not well-positioned to make timely and efficient investments in key areas, such as addressing shortfalls on their shared production lines or ensuring the economical sustainment and performance of the DDG 1000,” GAO stated.

As a result, the watchdog recommended that the Department of Defense develop and regularly review a comprehensive strategy to coordinate investments across all CPS-related programs.