Air Force Tests New “Re-Entry” Vehicle for Sentinel ICBM

By Jim Morris, Warrior Vice President, News

The US Air Force took another step toward developing its new reentry vehicle for the LGM-35A Sentinel intercontinental ballistic missile.

On Tuesday, an unarmed Mk21A RV was tested over the Pacific Ocean after being launched aboard a Minotaur I rocket from Vandenberg Space Force Base in California. The Air Force described the launch as an “in-flight environmental test..” Neither the Air Force nor Lockheed Martin, the reentry vehicle’s prime con tractor, released much information afterwards.

“Test launches like these are crucial for protecting our nation’s defense,” said Col. Mark Shoemaker, commander of Space Launch Delta 30 at Vandenberg.

“The Mk21A RV is crucial to addressing the rapidly changing global threat picture,” said Brig. Gen. William Rogers, the Air Force program executive officer for ICBMs. ”Its continued development and deployment will ensure a safe, secure and effective deterrent force the foreseeable future.”

In 2023, Lockheed was awarded a nearly $1 billion contract to develop a new reentry vehicle for the Sentinel, which will replace the Air Force’s aging arsenal of Minutemen III missiles. Once the new ICBM is operational, the Mk21A RV will house a modernized nuclear warhead, the W87-1.

Meanwhile, the Sentinel program has been hit by delays and cost overruns. The missile, whose prime contractor is Northrop Grumman, was originally scheduled for initial operational capability in 2029. That’s been pushed back by about two years.

It’s not just a new missile that’s being built. The program includes an overhaul of the silos, control centers and underground living quarters for the crews. Plus, the Sentinel is all digital and is replacing an analog weapon. That brings paradigm-changing speed and networking advantages but also requires additional security and hardening.