Explosion destroys building at Northrop Grumman rocket test site in Utah

Emergency responders were called to a Northrop Grumman manufacturing and testing facility Wednesday, April 16.

An explosion at the Promontory, Utah facility owned by aerospace and defense technology company Northrop Grumman was reported Wednesday, at 9:38 a.m. EDT (1338 GMT, 7:38 a.m., local time in Promontory). Emergency responders arrived to the scene to find one building completely destroyed.

“Initial reports indicate that there are no injuries or fatalities at this time,” the Box Elder Country Sheriff’s Office wrote in a social media post on Facebook. There were no injuries or fatalities associated with the incident.

Northrop Grumman’s Utah facility manufactures and tests solid rocket engines, like those used to launch NASA’s Space Launch System (SLS) rocket for the Artemis Program. Their campus spans over 10 miles (16 kilometers) of Utah desert, northwest of Promontory, with two central hubs of facilities.

Wednesday’s explosion destroyed a building in the northwest portion of Northrop Grumman’s northernmost collection of site infrastructure, about 8.5 miles (13.5 kilometers) north of the company’s test stand for the SLS solid rocket boosters.

Other buildings on the Northrop Grumman campus were unaffected by Wednesday’s incident. No cause for the explosion has been released, and the Box Elder County Sheriff’s Office said the investigation was ongoing, and advised the public to avoid the area.

As it so happens, the solid rocket boosters for Artemis 2 are already inside NASA’s Vehicle Assembly Building, at the Kennedy Space Center (KSC), in Florida. The pair have been mated to SLS’s core stage, which continues to undergo stacking ahead of Artemis 2’s scheduled launch in the Spring of 2026.

The manufacturing of Northrop Grumman’s solid rocket boosters for Artemis 3 was completed in 2022, and are being stored in Utah before being shipped to KSC for final assembly. Artemis 3 is currently scheduled for 2027.