The nuclear deterrence of a country depends on the nuclear triad.
A nuclear triad is the capability to launch nukes from air, sea & land.
The U.S.'s nuclear triad includes B-2 and B-52 bombers with nuclear bombs & missiles,
Ohio-class submarines armed with Trident II D-5 missiles, and Minuteman III ICBMs.
The Minuteman family of missiles has served as
the backbone of the U.S. land-based nuclear strategic force since 1962.
The Minuteman III began development in 1964 and entered service in 1970.
The number shrunk to around 450 by September 2017 and currently, there are about 400.
Over the years Minuteman III has been found to be extremely reliable
and several upgrades and life extension programs have kept it in working order.
But now it is reaching the end of its service life, a new ICBM is being developed.
In this video Defense Updates analyze how LGM-35A Sentinel is shaping up?
Let’s get into the details.
According to a senior US Air Force official, development of the US Air Force’s next-generation
intercontinental ballistic missile, the LGM-35A Sentinel, remains “on track” to
undergo a flight test later this year, although a US Defense Department report to Congress in
September showing an estimated 10-month slip in contractor Northrop Grumman’s development effort.
Brig. Gen. Ty Neuman, US Air Force director of concepts, said,
“The first flight test is still on track, and are still scheduled for this year.
We’re not gonna fly it, obviously, until it’s ready to go. And so without getting
into any more detail than that, we would expect first flight tests coming in ’23,”
US DoD’s most recent Selected Acquisition Report [PDF] on the progress of the Sentinel,
formerly called the Ground Based Strategic Deterrent,
said that due to “a schedule variance” in Northrop Grumman’s “baseline plan,”
Critical Design Review is estimated to move from July this year to May 2024.
It is to be noted that this date is within the US Air Force’s
“threshold” for declaring initial operating capability with 9 missiles on alert in 2029.
Northrop Grumman, has announced that it has successfully completed a series of wind tunnel
tests using scale models of the missile, as well as digital modeling and simulations,
that the company says has “proved design maturity.”
Sarah Willoughby, vice president and program manager, Sentinel, Northrop Grumman, said,
“This wind tunnel campaign is an opportunity to put our digitally engineered designs to the test,
under conditions that mimic a missile launch. Predictions from the modeling correlated with
the testing results, giving us confidence in our model-based engineering approach.”
The company also touted the program’s “advancements in technology with the
use of digital engineering, advanced tooling, and a modular, open-architecture approach.”
It is to be noted that Northrop is developing Sentinel using
digital engineering techniques and AI.
According to Neuman, the ability of the Sentinel to adapt to evolving threats throughout its
intended 40-year lifespan is attributed to the utilization of open architectures.
He said, “[T]he way we’re designing
all of our weapon systems at this point in time is the modularity and ability to adapt and change.
And what we realized is a rigid requirement that doesn’t have an open architecture in
the future is just not sustainable. By the time it’s actually delivered,
it’s OBE because the threat environment changes so much. So, Sentinel is going to be one of those
systems — it’s gonna have an open architecture that allows it to have flexibility in the future,”
A January “primer” by the Congressional Research Service (CRS) on the ICBM modernization effort
noted a number of advantages to the current development approach,
well beyond the ability to outsource future upgrades to vendors who might provide faster
and/or cheaper solutions, rather than being stuck with Northrop Grumman.
For example, CRS said, “These types of upgrades might become important as technology evolves and
could allow for improvements in the safety and reliability of the missile system.
They could include better guidance systems or new types of countermeasures that might allow
the missile to penetrate an adversary’s ballistic missile defensive systems.”
The report explained that the modular design coupled with the Sentinel’s increased “throw
weight” (payload carrying capacity) over the Minuteman III would allow the new ICBM
to potentially carry “different payloads” such as ballistic missile countermeasures.
Also, CRS stated, while the current service plan is to field 400 Sentinels each equipped with one
warhead — i.e., a one-on-one replacement of the Minuteman III arsenal — the modular
design and the increased throw weight all would enable each Sentinel to be equipped
“with two or three warheads to meet the international security environment.”
In other words, the Sentinels would most likely have multiple re-entry
vehicles (MIRVs), or potentially even maneuverable re-entry vehicles (MARVs).
The Strategic Arms Reduction Treaty (START) II of 1993, signed between the United States
and the former Soviet Union, prohibited the use of MIRVs. Nevertheless, after the US pulled out
of the 1972 Anti-Ballistic Missile Treaty, Moscow also withdrew from START II in 2002.
CRS added that “some argue” that MIRVing the Sentinels might allow the US Air Force “to meet
targeting requirements with a smaller number of deployed missiles,” thus reducing costs,
although it also would reduce the resiliency of the ICBM force.
Minuteman III has been the cornerstone of American land-based nuclear
deterrence for around 5 decades. It has been serving its purpose
but a new system is needed so that nuclear deterrence is not degraded in the coming days.
The U.S. needs to keep its land-based deterrence-fighting fit.
DoD’s Selected Acquisition Report put the total cost of the Sentinel acquisition program,
including the construction of new silos, at $95.8 billion.
American rivals like Russia are also investing in
a new generation of ICBM to keep their nuclear forces up to date.
The RS-28 Sarmat is a Russian liquid-fueled, MIRV-equipped ICBM under development by the
Makeyev Rocket Design Bureau since 2009. It is expected to replace R-36 Satan soon.
While the overall progress is looking good,
it remains to be seen if the stated timeline of Sentinel is actually achieved.