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Northrop To Test New Solid Rocket Booster Nozzle

United Launch Alliance webcast
Credit: United Launch Alliance webcast

CAPE CANAVERAL—Northrop Grumman plans to test a new nozzle for the Graphite Epoxy Motors (GEM) used on United Launch Alliance’s (ULA) Vulcan and Atlas rockets, a redesign that could be part of Vulcan’s return to flight following a malfunction of one of four GEM solid rocket boosters in February.

“The Northrop team had been working on a variation of a nozzle for multiple uses, and we’re going to do a static fire of that in the mid-April time frame,” in Utah, Gary Wentz, ULA vice president of Atlas and Vulcan programs, said in a March 30 interview with Aviation Week. “That may or may not be the nozzle we fly, depending upon the tests and what root cause we find as they go through the analysis.”

During Vulcan’s last flight on Feb. 12, one of the rocket’s four GEM 63XL solid rocket boosters experienced what appeared to be a burn-through. The anomaly was visible about 20 sec. after liftoff from Cape Canaveral SFS.

Despite the malfunction, the rocket’s guidance system was able to compensate and the USSF-87 payload successfully reached orbit. A similar issue occurred during Vulcan’s second flight on Oct. 4, 2024. Vulcan launches are on hold pending resolution of the issue.

A joint team of ULA, Northrop and the U.S. government have collected data from the USSF-87 launch, including debris recovery, for analysis, Wentz said.

“We’ve identified and located all four solid motors from the [USSF-87] mission and where they’re at in the ocean. Unfortunately, they’re a lot deeper than they were for Cert-2 [Vulcan’s second flight]. We carried them farther and there are four,” he said.

“They’re in roughly 2,500 ft. of water, which is beyond commercial [companies’] capability to recover. We have had some discussions with the government and are assessing jointly the value of recovering those motors,” Wentz added.

Irene Klotz

Irene Klotz is Senior Space Editor for Aviation Week, based in Cape Canaveral. Before joining Aviation Week in 2017, Irene spent 25 years as a wire service reporter covering human and robotic spaceflight, commercial space, astronomy, science and technology for Reuters and United Press International.