Second Stage Rocket of the U.S.’s Sentinel ICBM Tested
The test was conducted in vacuum conditions to simulate the extreme altitude conditions that the second stage will experience. The first stage of the missile was tested in March 2023. LGM-35 will keep the tradition of using solid-fuel rocket motors for boost stages.
LGM-35 Sentinel will replace the land-based LGM-30G Minuteman III ICBMs, which have been in service for over five decades. The three-stage missile is expected to enter service in 2028.
The new missile will use two new re-entry vehicles to deliver the nuclear warheads during the re-entry phase. First is the Mk21A, an improvement to the Mk21 carrying the W87 Mod 0 thermo-nuclear warheads. The second one will be a new design named Next-Generation Re-Entry Vehicle. The officials declined to give any information on the latter for security concerns.
The warhead will also be renewed with W87 Mod 1 warheads expected to offer a higher yield through refined secondary.