Northrop Grumman has released stunning visuals of the top of the U.S. Air Force's new LGM-35 Sentinel ICBM during a test test. This is a key part of the missile's function, and this "shield" needs to be safely separated before the nuclear warhead below is launched to the target. The successful test comes at a time when the Sentinel program has been facing serious challenges and billions of dollars in cost overruns, even though these issues are largely related to the need to modernize infrastructure, not the missiles themselves.
Rendering of the complete LGM-35 Sentinel ICBM.
*According to a press release issued today, the LGM-35 shield "fly-away" test was successfully conducted at the U.S. Navy's Naval Air ** Station test base in California. The press release adds that additional tests involving the upper and lower stages of the Sentinel missile were also recently conducted at the Northrop Grumman strategic missile test and production site in Cape, Utah. In addition to the shield test, this includes a "stack test" that demonstrates how the missile's lower stage is expected to behave in real flight. All this follows other successful tests of the Sentinel rocket engine and other components of the missile last year.
*Shown as an LGM-35A Sentinel Stage Solid Rocket Engine at the Northrop Grumman Test Facility in Cape, Utah, March 2, 2023.
"We worked with the Air Force and our team of merchants to test key elements of the missile hardware to mature our designs and mitigate risk," Northrop Grumman said in a statement. "Shroud flight tests have proven the reliability of our modeling**, while missile stack tests have demonstrated in-flight missile performance, helping to validate assumptions and fine-tune the model. "Sentinel is still under development, but the goal is for these new ICBMs to begin replacing the old LGM-2030G Minuteman III ICBMs in the 30s. The Air Force currently has about 400 Minuteman IIIs deployed in silos spread across five states.
Infrared image of the LGM-30G Minuteman III ICBM launched during routine tests.
According to the press release, the flight of the Shroud, in particular, verified that "the Shroud did not hit the closed payload, which was critical to the success of the mission." ** released by Northrop Grumman shows that with the help of a pair of rocket engines, the shield "rotates" down from the top of the missile. Currently, each LGM-35 is expected to be equipped with a W21-87 nuclear warhead inside the MK 1A reentry vehicle, which is connected to a payload bus under the top shroud. During the actual launch, the top stage of the Sentinel first rises beyond the Earth's atmosphere. At the designated point, the shield will be detached from the rest of the missile. Then the payload bus will maneuver into place and release the warhead. Modern ICBMs often carry decoys and have other countermeasures, complicating interception attempts and otherwise hindering defenders.
The exact yield of the W87-1 is unknown, but it is reported that the original W87 warhead had a base yield of 300 kilotons, which could be increased to 475 kilotons by modifying the second stage of the **. The W87 and its MK 21 reentry vehicle were originally developed for the LGM-118 Peacekeeper ICBM, which was put into service in the 80s of the 20th century. The last peacekeepers were decommissioned in 2005 as a result of the US-Russia arms control agreement. The warheads of these missiles were then modified for use on the older LGM-30G Minuteman III, which is the only ICBM in US inventory today.
The U.S. Air Force said it is ready to equip the LGM-35 with multiple warheads if such a decision is made in the future, a configuration known as a multiple independent target reentry vehicle. Existing Minuteman IIIs can be equipped with multiple warhead missile configurations, but these missiles are currently loaded with only a single warhead due to arms control agreements. The total number of nuclear warheads that the U.S. military can deploy at any one time, including the total number of nuclear warheads on ICBMs, is currently limited by the provisions of the New START Treaty. In 2021, the US and Russian authorities agreed to extend the agreement until 2026. However, Russia suspended its participation in the New START treaty last year, ostensibly because the United States continues to support Ukraine.
Air Force personnel maneuver the reentry vehicle on the Minuteman III ICBM payload bus. Due to arms control agreements, the currently deployed Minuteman III missiles are loaded with only one warhead.
The potential to arm the Sentinel with a highly maneuverable, unpowered hypersonic boost-glide vehicle, rather than a warhead inside a traditional reentry vehicle, has also been discussed in the past. Unfortunately, while the development of the LGM-35 missile itself looks to be progressing steadily, the Air Force admits that the entire program has been faltering. According to a January report by a U.S.-related magazine, the overall estimated cost of the Sentinel was initially expected to be just under $96 billion, but has now grown by about 37% to just over $125 billion. The plan also contemplates a postponement of at least two years. A comprehensive reassessment of the cost and timeline of the program is currently underway.
However, "one of the things we learned is that there hasn't been a significant increase in the missile side of the Sentinel program," said Kristen Jones, a senior member of the Sentinel program. Last week, the Secretary of the Air Force told The War Zone and others** at a **roundtable held on the sidelines of the 2024 Air Force & Space Force Association War Symposium. "This is mainly the civil engineering aspect of the program. It's a daunting task. ”
In addition to the development and procurement of LGM-35 missiles, the Sentinel program includes the modernization of hundreds of existing silos and launch control facilities, as well as other infrastructure and command-control-related improvements. "We're starting to see things that we thought could be reused now don't seem like possible," Jones explained. "And then there are macroeconomic factors such as inflation, ** chain, labor costs, etc. ”
Renderings of the future Sentinel Silo, which also highlighted that much of the facility is expected to be brand new.
Jones added that a full analysis of Sentinel cost growth** is still ongoing. The U.S. Air Force also announced last year that unsafe levels of carcinogens had been found at ICBM launch control facilities. This may be related to the large number of cancer diagnoses among current and former members of the military's missile community.
The Air Force has made it clear that they believe there is no alternative to the Sentinel, and that the ICBM program remains critical to the United States in the long run. At the same time, it remains to be seen how the plight of the "Sentinel" will affect other future plans and budgets of the Air Force.
I can't give up anything right now," Air Force Secretary Frank Kendall said at the same ** roundtable when he spoke to Jones last week. "If we have to pay a certain amount of money for the Sentinels, it will limit the amount of money we can use for everything else. I think the primacy of the mandate says a lot. "All in all, it remains to be seen what the full cost of the Sentinel program might end up being and how long it will take to complete most of the work. The newly announced flight tests of the shield really showed that work on the missile itself seems to be proceeding at a rapid pace.