Lockheed Martin Tests Mk21A Reentry Vehicle

An unarmed, developmental Mk21A reentry vehicle completed a flight test launched from Vandenberg Space Force Base in California.

Updated on Nov. 5, 2026 in Military

Bold flat-color editorial illustration of a smooth conical reentry body descending diagonally over an open ocean horizon, leaving a thin vapor trail under pale dawn sky. — Lockheed Martin and the U.S. Air Force completed a test flight of the unarmed Mk21A reentry vehicle over the Pacific Ocean from Vandenberg Space Force Base. AI Illustration. Upload story photo >

Lockheed Martin and the U.S. Air Force completed a test flight of the unarmed Mk21A reentry vehicle over the Pacific Ocean. The Mk21A is the front-end payload for the future intercontinental ballistic missile system and upgrades the legacy Mk21.

Why it matters

The flight test is intended to modernize the land-based leg of the U.S. strategic nuclear triad and addresses evolving adversary defenses. Data from the test will inform design refinements as the program moves toward system-level Critical Design Review.

The program is executed under a prime military contract valued at over $1 billion. The extraction provides no flight performance metrics, so measured results of the test remain unpublished.

The players

Lockheed Martin

Lockheed Martin is a major American aerospace and defense contractor that develops missile and space systems for the U.S. government.

U.S. Air Force

The U.S. Air Force is the military service branch responsible for the nation's air-based and land-based intercontinental ballistic missile forces.

The details

The test flight launched over the Pacific Ocean from Vandenberg Space Force Base in California. Lockheed Martin used high-fidelity modeling, simulation tools, data from previous tests, and digital engineering frameworks to compress development schedules.

The Mk21A test flight launched from Vandenberg Space Force Base on a date not specified in the source.
The program is progressing toward its system-level Critical Design Review, date not specified.

Roadmap

The Mk21A test is part of modernizing the land-based leg of the U.S. strategic nuclear triad, which includes land-based, sea-based, and air-based strategic forces. The program's progress toward Critical Design Review reflects that broader modernization effort.

The Mk21A is an unarmed, developmental program, so no immediate action is required from the public. Residents near Vandenberg Space Force Base may notice launch activity associated with ongoing testing.

The takeaway

The Mk21A flight test marks a step toward modernizing the land-based leg of the nuclear triad. Results from this test will shape the design refinements that precede the program's Critical Design Review.