Jane Edwards 
- Lockheed Martin has moved Mk21A closer to critical design review
- The vehicle is being designed for the Sentinel ICBM
- The 2027 Defense R&D Summit will explore trusted AI, assured connectivity and more
Lockheed Martin and the U.S. Air Force have completed a flight test of the unarmed, developmental Mk21A reentry vehicle for the service’s future intercontinental ballistic missile, or ICBM, system.
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The company said Wednesday the vehicle launched from Vandenberg Space Force Base in California and flew over the Pacific Ocean. Lockheed conducted the test under a prime contract valued at more than $1 billion.
What Did the Flight Test Demonstrate?
The flight test showed the maturity of the Mk21A’s architecture and confirmed the performance of its new reentry technologies.
To accelerate development, Lockheed drew on findings from earlier tests and applied digital engineering methods. These methods rely on detailed computer modeling and simulation to shorten development timelines, improve efficiency, reduce technical risk and confirm the system performs as intended.
Information gathered during the latest flight will feed into continuing design updates and future test planning as the program works toward its system-level critical design review.
Jason Watson, vice president of strategic reentry programs at Lockheed, said testing is a key driver of maturity and reliability in modern defense programs.
“Building on flight data from our prior tests, we are directly translating real-world experience into program momentum, ensuring the Mk21A reentry vehicle delivers uncompromised performance for the Air Force,” Watson added.
What Is Mk21A?
Mk21A is the Air Force’s next-generation integrated reentry vehicle designed to serve as the front-end payload of the future ICBM system. The vehicle is an upgrade to the legacy Mk21 and supports the modernization of the land-based leg of the U.S. strategic nuclear triad.
How Does the Mk21A Fit Into Lockheed’s Strategic Portfolio?
The latest flight test continues Lockheed’s development of the Mk21A, which is being designed to carry the W87-1 warhead for the Sentinel ICBM. The company flight-tested an unarmed Mk21A from Vandenberg in 2024 and received a $454 million Air Force contract modification for the program in November 2025.
Lockheed is also the prime contractor for the Navy’s Trident II D5 submarine-launched ballistic missile. It secured an $850 million contract modification for the Trident II D5 Life Extension 2 program, following a $647 million modification for missile production and deployed systems support.
For the Missile Defense Agency’s Next Generation Interceptor, the company completed a burst test of the second-stage motor case and opened a manufacturing facility in Courtland, Alabama.
In hypersonics, Lockheed received a $694 million Air Force contract to produce the AGM-183A Air-Launched Rapid Response Weapon, unveiled a next-generation hypersonic glide body and secured a $1.35 billion Navy contract modification for the Conventional Prompt Strike program.
