US Navy extends Trident II missile testing through 2031 ahead of Columbia-class submarine entry into service.

The U.S. Navy awarded L3Harris Technologies division Interstate Electronics Corporation a $46.85 million contract on October 1, 2026, to sustain Trident II D5 flight-test instrumentation through September 30, 2031. The agreement provides critical engineering, logistics, and telemetry support to measure missile trajectory, guidance accuracy, and reliability. This instrumentation infrastructure supports ongoing evaluations of deployed D5LE systems while preparing diagnostic architectures for the upcoming D5LE2 life extension program.

The multiyear contract carries options raising its potential ceiling to $207.05 million to maintain test systems across facilities in California, Florida, and Washington. The diagnostic architecture processes telemetry, tracking, and guidance parameters to evaluate missile performance ahead of the transition to Columbia-class ballistic missile submarines.

Related topic: US Air Force completes vertical assembly of first Sentinel ICBM ahead of 2027 flight tests

The Trident II D5 was developed from the late 1970s as the longer-range and higher-payload successor to the Trident I C4, entered U.S. service aboard Ohio-class SSBNs in 1990, and was subsequently adopted by the UK for Vanguard-class submarines (Picture source: US DoD)

On October 1, 2026, the U.S. Navy awarded L3Harris's division Interstate Electronics Corp. (IEC) $46.85 million to sustain Trident II D5 flight-test instrumentation through September 30, 2031, with options raising the potential ceiling to $207.05 million, as the first Columbia-class ballistic missile submarine, the USS District of Columbia (SSBN-826), is slated to begin its first operational nuclear deterrent patrol in 2030. The $160.2 million optional portion represents 77.4% of the maximum value, while no funding was obligated at award because performance depends on FY2027 funding availability. The contract covers engineering, logistics, installation, operation, maintenance, and modification of Navy-owned instrumentation that measures missile trajectory, navigation, guidance, accuracy, and reliability during unarmed launches, rather than the procurement of additional D5 submarine-launched ballistic missiles (SLBMs).

The contract therefore covers the measurement infrastructure needed while the U.S. Navy continues testing the D5LE (D5 Life Extension Program) and prepares the D5LE2 (D5 Life Extension Program 2) for a planned FY2039 fleet introduction. The work is concentrated at Yorba Linda, California, which receives 55% of the workload and is the principal Interstate Electronics location for Trident flight-test instrumentation, while Cape Canaveral, Florida, receives another 30%, as the planned site for as many as 10 land-based D5LE2 flight tests between 2032 and 2036. Washington, D.C., the location of the Strategic Systems Programs, the Navy organization responsible for the submarine-launched strategic weapon enterprise and the contracting activity, accounts for 7%.

The home of General Dynamics Electric Boat, prime contractor for the Columbia-class, receives 3%; Bremerton, Washington, at 2%, and Kings Bay, Georgia, at 2%, connect the contract to the Ohio-class SSBN infrastructure on both U.S. coasts. Barrow-in-Furness, with 1%, represents the British component of the contract as the site where BAE Systems is constructing the Royal Navy's four Dreadnought-class SSBNs. Separately, on October 2, BAE Systems received a separate $70.52 million contract for Trident II technical support and facilities engineering through September 30, 2031, including 68% of its work in Washington, 16% at Kings Bay, and 16% at Bangor. The instrumentation supported by L3Harris measures substantially more than the final Trident II D5 impact point.

Missile-borne telemetry records guidance, inertial navigation, and performance parameters, while the SATRACK compares navigation system information with independently measured tracking data to reconstruct where trajectory errors developed. The test architecture also uses M345 Flight Test Support System processors, S-band telemetry, electrically steered antennas, X-band Doppler radar, optical tracking and communications equipment, with receivers capable of collecting separate missile and reentry-body telemetry streams. This allows engineers to distinguish guidance or navigation error from other vehicle effects and calculate reliability and accuracy from the complete flight rather than a binary successful-or-unsuccessful launch result. That equipment follows a 59,000 kg three-stage solid-propellant missile whose flight changes rapidly from launch through post-boost operations.

The Trident II D5, also designated UGM-133A, is 13.579 m long with a first-stage diameter of 2.11 m; published figures give a range of 7,593 km with eight Mk5 reentry vehicles and 11,519 km with four, a 51.7% increase as throw-weight falls from 2,700 to 2,000 kg. Launch begins below the surface when a gas and steam system expels the missile from its tube, before first-stage ignition after the missile has emerged from the water, after which the first and second stages burn for 65 seconds each and the third for 40 seconds, giving about 170 seconds of powered three-stage flight. After that, the Post Boost Control System maneuvers the reentry-vehicle section for deployment, including Plume Avoidance Maneuvers that prevent control-nozzle exhaust from disturbing a released reentry vehicle. The Mk 6 astro-inertial guidance system, for its part, uses inertial navigation as its primary reference and stellar observations to correct accumulated navigation error during flight.

Flight instrumentation consequently has to characterize a chain including underwater ejection, surface broach, propulsion, separation, guidance correction, and post-boost events within the same test. The workload is likely to become more demanding as the D5LE2 advances, as the US Navy has to continue monitoring the deployed D5LE force while increasing the number of potential tests for its successor during the contract period. Four D5LE missiles were launched between September 17 and 21, 2025, raising the cumulative total to 197 successful D5 flight tests. As the U.S. Navy permits up to six sea-based tests annually between 2025 and 2028 and eight annually between 2029 and 2039, those ceilings equal as many as 112 sea-based tests across 15 years, plus up to 10 land launches from Cape Canaveral between 2032 and 2036.

Sea launches occur from submerged submarines more than 100 ft below the surface and at least 50 nautical miles offshore, while spent components and test articles are planned to enter ocean areas at least 200 nautical miles from land. The land tests, for their part, are intended to qualify the D5LE2's technologies before submarine deployment, creating a second instrumentation workload alongside continuing surveillance of the existing D5LE missiles. The development of the Trident II D5LE2 already includes hardware that must reproduce the loads encountered during an actual launch. FY2026 work funds three inert first-stage vehicles, three second-stage vehicles and three third-stage vehicles for development testing, alongside prototype missile avionics, flight performance modeling and preparations at the Eastern Range, Strategic Weapons Facility Atlantic and Strategic Weapons Facility Pacific.

Structural work covers the equipment section, motor equipment module, nose fairing and interstage against conditions including free hoist, closure impact, surface broach and maximum flight pressure buckling, while vibration and acoustic tests reproduce dynamic flight environments. Electronics work includes the Primary Electronics Battery, Power Distribution Unit, Remote Units, Safe Arming and Fuzing Electronics, communications network, Missile Test and Readiness Equipment and associated cabling and connectors. The L3Harris instrumentation contract therefore supports a transition in which the D5LE remains operational as the upcoming D5LE2 moves from subsystem and structural qualification toward complete flight vehicles. 

The missile transition also overlaps a measurable reduction in U.S. SSBN missile capacity. Fourteen Ohio-class SSBNs currently provide 280 operational tube positions at 20 per submarine, after four of the original 24 tubes on each boat were deactivated in 2017; the future 12 Columbia-class SSBNs with 16 tubes each will provide 192, a reduction of 31.4%. The Columbia-class nevertheless displaces 20,810 long tons submerged compared with 18,750 for Ohio-class subs and is designed for 42 years and 124 deterrent patrols with a life-of-ship reactor. The D5LE will initially arm the Columbia-class, as the U.S. Navy wants to avoid qualifying a new submarine and the D5LE2 simultaneously, because the D5LE2 is intended to sustain the Trident beyond 2039 and through the 2080s.

The same transition also covers the British Royal Navy's four Vanguard SSBNs and four planned Dreadnought SSBNs. Vanguard, Victorious, Vigilant and Vengeance use Trident missiles associated with the shared U.S.-UK inventory at Kings Bay, while Dreadnought, Valiant, Warspite and King George VI use the Common Missile Compartment architecture also incorporated into Columbia. Britain participates in D5LE2, making U.S. missile qualification relevant to both future SSBN fleets, while the 1% Barrow-in-Furness share of the L3Harris contract connects the instrumentation effort with the yard building Dreadnought.

Explore More Defense News

• Land Defense News
• Naval Defense News
• Defense Aerospace News

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, South Korea, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.