Northrop Grumman examined the motor within the vacuum chamber in collaboration with the U.S. Air Pressure, persevering with the event of the Minuteman III’s alternative.
Northrop Grumman has take a look at fired the second-stage stable rocket motor of the LGM-35A Sentinel ICBM (Inter-Continental Ballistic Missile) in collaboration with the U.S. Air Pressure at Arnold AFB in Tennessee. The total-scale qualification take a look at was carried out on Jul. 20, 2025, and introduced on Jul. 29 by each the corporate and the Air Pressure Nuclear Weapons Middle (AFNWC).
Overseen by the 717th Take a look at Squadron and the Arnold Engineering Growth Take a look at Advanced, the ground-based fireplace of the Sentinel’s second stage rocket motor was “carried out in a vacuum chamber to simulate high-altitude circumstances,” defined the Air Pressure. The take a look at generated very important information on the “motor’s thrust, burn profile, and steering capabilities by way of its thrust vector management system.”
Extra stage-two qualification checks within the the rest of 2025 will “consider further motor parts below diverse environmental circumstances.” This stage has already been examined in the same method, in line with January 2024 Air Pressure and Northrop Grumman statements.
The event follows the stage-one rocket motor’s full-scale qualification static fireplace take a look at in Mar. 6, 2025 at Northrop Grumman’s Strategic Missile Take a look at and Manufacturing Advanced in Promontory, Utah. This validated the motor’s anticipated efficiency parameters with digital fashions, setting the stage for the newest stage-two trials.
The Sentinel staff carried out a stage-two static take a look at. Try how we’re working with the @usairforce to cut back danger and totally qualify motor design.
Photograph courtesy of the U.S. Air Pressure. pic.twitter.com/CWhhOeCRgm
— Northrop Grumman (@northropgrumman) July 29, 2025
The corporate beforehand carried out a “shroud fly-off take a look at” at Naval Air Weapons Station China Lake, a “stack take a look at” at Promontory to guage the ahead and aft sections, and wind tunnel take a look at of the ultimate stage’s car holding the warhead. Northrop Grumman says the corporate and the Air Pressure have test-fired all three phases individually, validating digital engineering fashions and simulations to “enhance efficiency, reliability, security, and sustainability.”
Second-stage take a look at
The LGM-35 Sentinel is a three-stage missile, thus together with three booster segments. The most recent take a look at validated the second stage’ design and predictive efficiency fashions developed in a digital engineering surroundings, the AFNWC stated. The testing information gathered will assist “refine design components and cut back technical danger as this system strikes towards manufacturing.”
The Sentinel program’s model-based design method helps “simulate system conduct, enhance accuracy in efficiency predictions, and cut back reliance on pricey {hardware} prototypes,” in line with the AFNWC launch. Northrop Grumman’s assertion stated digital engineering has helped keep away from “bend metallic” work for every design enhancement.
Nonetheless, digital engineering can solely complement and never fully exchange some checks. As an example, the live-fire qualification checks of the stage-two motor decide whether or not the parts “meets the Air Pressure’s exacting requirements for high quality and reliability.”
“Northrop Grumman and the Air Pressure have examined all three phases of the Sentinel missile,” stated Northrop Grumman’s press launch. “This take a look at is the primary of a sequence meant to validate digital fashions and finalize the stage-two rocket motor design. Every take a look at will confirm totally different motor parts to cut back danger and refine the design. This take a look at follows earlier checks of each stage-one and development-stage motors, offering crucial information for continued progress in missile design, testing and assist methods
Equally, the stage-one rocket motor checks carried out in Mar. 6, 2025, verified the digital engineering fashions and adopted “static fireplace checks of the second and third phases, showcasing clear momentum within the Sentinel program’s improvement.”
The AFNWC assertion quoted director of the ICBM Methods Directorate Brig. Gen. William S. Rogers, who stated the newest take a look at “displays our disciplined digital engineering method and the continued momentum behind the Sentinel program.” Moreover, Rogers defined “we’re not simply testing {hardware} (however) proving that our fashions are correct, our improvement timeline is achievable, and the system will probably be able to ship.”
We’re partnering with the @usairforce to ship Sentinel —an ICBM system offering game-changing functionality, wanted enhancements for missileers and strategic deterrence in opposition to evolving threats by way of 2075. pic.twitter.com/8muFiePLkE
— Northrop Grumman (@northropgrumman) June 18, 2025
Different checks
As talked about earlier, the Air Pressure and Northrop have demonstrated all propulsive components of the Sentinel missile. These checks are a part of the engineering, manufacturing, and improvement (EMD) part of this system.
Beside the take a look at firing stages-one, two and three, a “hot-fire” of the Publish Increase Propulsion System (PBPS) has additionally been carried out. The liquid gasoline PBPS propels the Publish Increase Angle Management Module, “accountable for positioning the reentry car throughout exo-atmospheric flight,” in line with Northrop.
Interstage separation checks of the Sentinel missile demonstrated its capacity to “cleanly separate the spent stable rocket motor phases one and two from the remainder of the car, crucial to the flight staging sequence.” Wind tunnel checks of scale fashions of the final stage car, which carries the warhead, checked it below sub-hypersonic to hypersonic speeds to match the design’s maturity with digital modelling and simulations.
Lastly, the joint Northrop and Air Pressure staff additionally inspected 16 current silos and used these observations to construct a mock-up of a Minuteman decrease launch tube at Hill AFB, Utah. The tube “included quite a lot of built-in circumstances to simulate put on and tear.”
Sentinel ICBM’s huge infrastructure
The U.S. Air Pressure stated prior to now it was prepared to conduct a staggering quantity of Sentinel-centric infrastructure work like underground launch silos, entailing excavations at or past 80 ft deep at round 400 websites throughout continental U.S. Current Minuteman III silos are primarily based in Wyoming, North Dakota, Montana, Colorado, and Nebraska. New silos could be required additionally at Vandenberg SFB for take a look at launches.
A significant driver of the 81% spike within the Sentinel’s estimated value to $140 billion that triggered a Nunn-McCurdy Evaluate, beside the unexpected new silos and command and management services, was additionally represented by the associated upkeep gear, communications suites, encryption methods, electronics, software program, wiring and cabling methods.
Talking on the Superior Nuclear Weapons Alliance Deterrence Middle on Apr. 30, 2025, AFSC (Air Pressure World Strike Command) Gen. Thomas Brussiere additionally dominated out the choice of reusing the older silos holding the present Minuteman III ICBMs – a route it presumably briefly thought of.
“A part of the necessities, initially – ten years in the past when this program was began – was to reuse the holes, the missile holes on the launch services,” defined Brussiere. “That was believed to be extra environment friendly, more economical and faster. Shockingly sufficient, if we have a look at it now, that will not be the reply.”
The Air Pressure has but to take its resolution on that entrance or, if it has already, has not but made it public. Northrop Grumman, in a Jun. 2025 video on the Sentinel, has put the full variety of missiles at 450, an equal variety of unmanned launch services and 24 all new LCC (Launch Management Facilities) – reflecting what everything of what the big program encompasses.
Fiber optic cables 5,000 miles lengthy in the meantime will join launch services and LCCs throughout the 91st Missile Wing, 341st MW and ninetieth MW, masking 32,000 sq. miles throughout 5 states.
