VANDENBERG SPACE FORCE BASE, California — The U.S. Air Force, managed by the Air Force Nuclear Weapons Center (AFNWC), successfully executed an in-flight environmental test launch of the developmental, unarmed Mk21A Reentry Vehicle (RV) on October 9, 2026.
The experimental test payload was launched aboard a solid-propellant Minotaur I launch vehicle supplied by Northrop Grumman, under the operational oversight of the U.S. Space Force’s Rocket Systems Launch Program (Space Launch Delta 30). The mission evaluated aerodynamic stability, thermal heatshield integrity, and internal sensor performance in an operationally realistic flight profile. The Mk21A RV is under Engineering and Manufacturing Development (EMD) with prime contractor Lockheed Martin under a $996 million contract to host the W87-1 nuclear warhead, ultimately replacing legacy Mk12A and Mk21 reentry systems on the upcoming LGM-35A Sentinel ICBM.
TECHNICAL SPECIFICATIONS: USAF / LOCKHEED MARTIN MK21A REENTRY VEHICLE 
* Prime Contractor & Acquisition Lead: Lockheed Martin Space (EMD Phase) / Air Force Nuclear Weapons Center (AFNWC)
* Program Context & Modernization Objective: Next-generation reentry vehicle for the Northrop Grumman LGM-35A Sentinel ICBM (replacing LGM-30G Minuteman III)
* Launch Support Platform: Northrop Grumman Minotaur I Launch Vehicle (4-stage solid-fuel booster combining Minuteman motors with Pegasus upper stages)
* Launch Management: U.S. Space Force Space Launch Delta 30 / Rocket Systems Launch Program (RSLP)
* Warhead Integration Architecture:
* Assigned Nuclear Payload: W87-1 Mod 0 thermonuclear warhead (NNSA weapon modernization program)
* Predecessor Baselines: Upgraded derivative of the legacy Mk21 RV (originally deployed on Peacekeeper and Minuteman III)
* Technical Capabilities & Key Test Parameters:
* Flight Envelope Testing: Suborbital atmospheric re-entry thermal, acoustic, vibration, and structural load characterization
* Thermal Protection System (TPS): Carbon-carbon composite heatshield and advanced nose-cone aerodynamic geometries
* Avionics & Arming Subsystems: Integrated Arming, Fuzing, and Firing (AF&F) subsystem and modern safety architecture
* Warhead Security: Nuclear safety, security, and yield control upgrades complying with modernized AFGSC operational requirements
