An explosion on April 16 destroyed a building at Northrop Grumman’s Innovation Systems plant in Promontory, Utah, where the company produces solid rocket motors for US government and commercial clients.
There were no immediate reports of casualties from the blast, which occurred at 7:35 am local time. Local authorities confirmed they are investigating the incident.
Northrop Grumman officials stated that the accident would not disrupt any ongoing programs. The U.S. Air Force referred inquiries to Northrop Grumman.
A Northrop spokesman did not specify the function of the destroyed building or whether it was linked to the production of solid rocket motors (SRMs). However, industry sources informed Air & Space Forces Magazine that the building partly stored materials used to manufacture SRMs.
Northrop Grumman’s Innovation Systems—previously known as Orbital ATK—holds almost 90% of the U.S. SRM capacity, supporting programs for the Air Force, NASA, and commercial space launches.
A local TV station captured footage of the wreckage from a helicopter, revealing significant damage but no ongoing fire.
Of particular interest to the Air Force, Northrop plans to use large solid rocket motors it has developed in-house for the LGM-35A Sentinel intercontinental ballistic missile. However, Northrop officials confirmed that the destroyed building was not associated with the Sentinel program.
The facility is located to the north of the Great Salt Lake and northwest of the Ogden Air Logistics Complex, which manages Minuteman III rocket motor maintenance, among other systems.
The site now operated by Northrop Grumman was once the Thiokol company, acquired by Alliant Tech Systems in 2001. Alliant Tech Systems merged with Orbital Sciences Corp. in 2015, and three years later, Northrop acquired Orbital/ATK.
Northrop’s dominance in SRM production led to the company being required to serve as a merchant supplier of SRMs to Boeing during the competition for the Ground-Based Strategic Deterrent (now the Sentinel system). Northrop won the contract in 2020 after Boeing withdrew, citing an inability to compete with Northrop’s SRM advantage.
Aerojet Rocketdyne, now part of L3Harris since 2023, is the second-largest SRM producer in the U.S.
