WASHINGTON — The Pentagon has warned that shortages of solid rocket motors could constrain plans to sharply increase missile production. One of the industry’s largest suppliers says the bigger challenge may be how the government buys them.
Northrop Grumman, one of only two dominant U.S. producers of large and medium-sized solid rocket motors, argues that industry has substantial capacity to expand production but needs longer-term procurement commitments to justify investments throughout the supply chain.
The debate comes as the Defense Department prepares for a significant increase in missile procurement. A recent report by the Center for Strategic and International Studies concluded that solid rocket motors remain a bottleneck across the U.S. missile industrial base just as the Pentagon seeks to rapidly expand production of air and missile-defense interceptors.
James Kalberer, vice president of Northrop Grumman’s propulsion systems business unit, said manufacturers are responding to those concerns and are prepared to increase output. But he said annual appropriations and shorter-duration contracts make it difficult to make the long-term investments needed to support sustained growth.
In an interview with SpaceNews, Kalberer that while government demand signals are being heard, suppliers need greater confidence that procurement plans will endure beyond annual budget cycles.
The Pentagon has embraced multiyear authority for munitions contracts and has made direct investments in suppliers. But multiyear procurement programs ultimately depend on annual congressional appropriations. Congress can change funding levels, terminate programs, or alter priorities which creates uncertainty. Another issue is that the Pentagon’s multiyear authorities are program-specific rather than supply-chain-wide. A prime contractor may have confidence in demand for a missile program, but a second- or third-tier supplier making materials or propellant chemicals may not see enough contractual certainty to justify a major factory expansion.
Kalberer said Pentagon efforts are helping. “One thing that the government can do, and that we’re starting to see them do, is to give longer demand signals so that we can respond and work with our supply chains to ensure readiness at all levels,” he said. “With commitments to multiyear procurements, you’d see all parts of the ecosystem able to respond more quickly versus what has traditionally been done in year to year types of requirements.”
Expanding rocket-motor production requires investments that extend well beyond the prime contractor, he said, including raw-material suppliers, nozzle manufacturers, insulation producers, propellant ingredient suppliers, workforce development and facility expansion.
More than $1 billion invested
Kalberer said Northrop Grumman has committed more than $2 billion across its munitions and solid rocket motor businesses over the past several years, including more than $1 billion dedicated specifically to solid rocket motors.
“Capacity is online to support the need,” he said.
In his view, the industry’s challenges can be addressed largely through procurement reforms.
“What we’ve seen is really suppliers willing to step up and certainly make their own investments if that’s required, if those demand signals are clear,” Kalberer said. “The next step that the government can take is working through the acquisition process to ensure that there’s multiyear confidence in how they will procure those systems over time versus year to year procurements, where you’re staffing and bringing online investments to support a longer term commitment to the production.”
Northrop occupies a unique position in the solid rocket motor market. The company’s propulsion business traces its roots through Hercules Aerospace, Alliant Techsystems and Orbital ATK before Northrop acquired Orbital ATK in 2018. The acquisition gave Northrop ownership of one of the two major domestic solid rocket motor franchises. The other is the former Aerojet Rocketdyne business, now part of L3Harris Technologies.
Northrop’s solid rocket motor business extends beyond missile programs. The company manufactures the twin solid rocket boosters for NASA’s Space Launch System, the heavy-lift rocket developed for the Artemis moon program.
Kalberer said Northrop delivered roughly 13,000 rocket motors in 2024 and expects production to reach about 25,000 annually by 2029.
The company points to existing capacity that could be further utilized.
“Propellant production takes very heavy infrastructure,” Kalberer said. “We’re currently producing 30 million pounds of propellant, and as you translate that into quantities of rocket motor, we have available capacity today for 50 million pounds of propellant.”
Qualifying new tech and vendors
Part of Northrop’s strategy for increasing throughput involves accelerating the pace at which new technologies and suppliers can be qualified.
Kalberer said the company is now in the fifth year of an internally funded initiative known as SMART Demo, short for Solid Motor Annual Rocket Technology Demonstrator. The program was created to test new manufacturing methods, materials and suppliers before introducing them into production programs.
The effort addresses a longstanding challenge in the rocket-motor industry: qualifying new products and vendors can take years even as military demand changes rapidly.
According to Kalberer, SMART has helped reduce the time from design to qualification testing from as much as three years to between 12 and 18 months while also helping bring new suppliers into the ecosystem.
The Pentagon has pursued other approaches to expanding capacity. A number of new entrant startups have won contracts to develop solid rocket motors. The Pentagon in April completed a $1 billion investment in L3Harris’s missile propulsion business, a move intended to accelerate expansion of solid rocket motor production.
Asked whether Northrop would welcome a similar investment, Kalberer declined to speculate.
“I can’t speak to what the government’s plans might be specific to Northrop Grumman, nor can I speak to their strategy necessarily in making other investments,” he said. “We put a lot into working directly with the customers at the prime level or within the government to understand where they have critical needs.”
The discussion about capacity comes as Northrop’s rocket-motor business faces scrutiny in another area.
Earlier this year, the Space Force paused national security launches on United Launch Alliance’s Vulcan rocket following a second anomaly involving a Northrop-built solid rocket booster in less than two years. Investigations into the most recent incident remain ongoing.
Kalberer said Northrop continues to support ULA’s Atlas launch operations and is working with the company on Vulcan’s return to flight.
“We are very much aligned with their manifest and their needs, and working with them to return Vulcan to flight,” he said.
