Against the backdrop of a program marked by major cost overruns and technical challenges, the U.S. Air Force is working with Northrop Grumman to accelerate the development of its new Sentinel intercontinental ballistic missiles, which are intended to become one of the future pillars of the service’s nuclear deterrence capabilities. According to information released by the manufacturer through official channels, its current roadmap foresees conducting the first flight tests during the course of next year, while initial operational capability is also expected to be achieved in 2030.
In that regard, Northrop Grumman has stated that the work is being carried out under a new incremental approach intended to move through the different development phases as quickly as possible, facilitating matters such as testing and evaluation, making any necessary adjustments, and addressing the logistical aspects of deployment. To make this possible, the company highlighted that more than 13.5 billion dollars were invested over the last five years to improve its infrastructure and R&D capabilities, of which around 2 billion were allocated specifically to the development of the rocket motors that will equip the future Sentinel missiles.
Sarah Willoughby, vice president and general manager of strategic deterrent systems at Northrop Grumman, referred to the matter by stating: “The Sentinel program exemplifies what is possible when a bold acquisition approach is paired with continuous innovation. Our dedicated team and extensive partner network are united by a common purpose: to field the Sentinel weapon system rapidly and at scale, while delivering enhanced capability to the U.S. Air Force.”
Another noteworthy aspect, derived from lessons learned during the development of the U.S. Air Force’s B-21 Raider bomber, lies in the greater use of digital design tools that have streamlined processes and enabled initial evaluations to verify the functioning of the Sentinel missile. As an example of this, Northrop Grumman highlighted that the new motors were designed with a new anti-corrosion composite material which, during testing, proved to be up to 70% lighter than those used in the Minuteman III missiles currently fielded by Washington.
Along those lines, it should be noted that the design has already moved into a prototype manufacturing stage, and those prototypes have already been seen in various tests to verify their operation. Reviewing some of them, one can mention testing of the new missile’s guidance and control system, which assessed its ability to function under conditions similar to those of a real flight. Two separation tests were also conducted, evaluating the Sentinel missile’s performance when the first and second stages of the motor separate once expended, as well as the protective coverings that shield its payload.
Challenges faced by the Sentinel program
As highlighted in the opening lines, it is important to consider that the U.S. Air Force has faced various challenges in carrying out development of the Sentinel program, both at the technical and economic levels. This is by no means a minor issue, considering that more than 600 units are planned for incorporation in order to modernize U.S. deterrence capabilities, mainly at bases in the so-called Great Plains located in the central continental territory of the country.
Reviewing these obstacles, it is worth recalling that the Sentinel program was subjected to an extensive investigation and evaluation by the U.S. Congress due to the considerable cost increases associated with it, which even exceeded the 25% threshold above the baseline cost established by the Nunn-McCurdy Act. Reports at the time even spoke of increases of up to 81% identified by the Cost Assessment and Program Evaluation (CAPE) office, which in concrete terms translated into around 141 billion dollars. That made it necessary for the Under Secretary of Defense for Acquisition and Sustainment to make a presentation before Congress to justify the program’s continuation.
When identifying the causes of this major additional cost, reports pointed out that the new missiles must be stored in the silos that currently house the aforementioned Minuteman III missiles, whose structure requires modifications in order to operate the Sentinel in the future. At this point, it should be mentioned that Northrop Grumman has already begun work on a new prototype launch tube intended to validate the design and the manufacturing process, a measure aimed at reducing the risk of potential failures and derived additional costs. In addition to that, the company also completed the critical design review of its new Launch Facility Support Systems, as well as validating ground transport capabilities to move the missiles to their silos.
Arguing for the program’s importance in order to convince Congress that it was necessary to continue these efforts, Dr. William A. LaPlante stated: “We are fully aware of the costs, but we are also aware of the risks of not modernizing our nuclear forces and not addressing the very real threats we face (…) The nuclear triad is the foundation of our national defense, and as our competitors modernize their own nuclear forces, the urgency of addressing the threat is reflected in our Nuclear Posture Review.”
For now, the program continues on course with the stated goal of achieving initial operational capability at the beginning of the next decade, with a U.S. Air Force that intends to keep them in its arsenal at least until 2075.
Images used for illustrative purposes
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