ULA’s Vulcan Nails Cert-2 Orbit Despite SRB Nozzle Issue

United Launch Alliance’s new Vulcan Centaur rocket conducted an unintended extra demonstration of its capabilities during the second demonstration flight ahead of missions for the U.S. military.

About 12 sec. after liftoff from Cape Canaveral SFS on Oct. 4, the nozzle on one of the rocket’s two Northrop Grumman Graphite-Epoxy Motor 63XL Solid Rocket Boosters (SRB) was released, resulting in a loss of thrust and a modest reduction in total impulse. Tracking cameras showed sparks and what appeared to be debris flying off the base of the right-side SRB about 37 sec. into the flight, followed by an immediate change in the shape of the booster’s exhaust plume.

“It looks dramatic, like all things on a rocket,” United Launch Alliance (ULA) CEO Tory Bruno wrote on social media site X after the launch. “But it’s just the release of the nozzle. No explosions occurred.

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“Nozzles can’t really ‘explode,’ ” he added. “They can liberate, as this one did. On a large, nonvectorable SRM [solid rocket motor], this results in a loss of thrust and a modest reduction in total impulse. [It] rarely presents any catastrophic risk to the SRM itself, because the pressure vessel is not involved.”

The 72-ft.-long SRBs separated from the vehicle about 20 sec. later than expected, according to a pre-launch flight timeline, leaving the rocket’s core stage—powered by a pair of Blue Origin BE-4 engines—to send the rocket beyond the atmosphere. Stage separation, ignition of the Centaur upper stage and shutdown after its initial burn likewise occurred about 20 sec. later than on the nominal timeline.

The SRB anomaly required the system to use less than 20% of the available performance excess allocated for mission contingency, ULA wrote in an email to Aviation Week. “Orbital insertion was perfect,” Bruno noted on X.

The 202-ft.-tall Vulcan Centaur rocket lifted off from Space Launch Complex 41 at 7:25 a.m. EST to begin the Certification-2 (Cert-2) mission. Initially, ULA hoped the mission also would provide launch services for Sierra Space, which is preparing its Dream Chaser winged spaceplane for a debut cargo run to the International Space Station.

But the Dream Chaser would not have been ready to fly before ULA had to complete Vulcan certification in time for a higher-priority National Security Space Launch (NSSL) mission this year. Instead of the spaceplane, ULA flew a nondeployable, 3,366-lb. mass simulator outfitted with instruments to test technologies to expand the capabilities of the rocket’s Centaur V upper stage, including the ability to support space operations lasting weeks to months. The Dream Chaser was rescheduled for launch on another Vulcan in 2025.

Cert-2 featured about 30 min. of Centaur V operations following first-stage separation, including a second firing of its Aerojet Rocketdyne RL10C engines that served to reorient the vehicle for a simulated primary payload release and to demonstrate the ability to restart in space—a requirement for upcoming NSSL missions. The Centaur V was then put into a solar-orbiting disposal orbit.

The company’s initial assessment of Cert-2 operations is expected to take about two weeks. “The anomaly investigation is underway, and when the team determines root cause, we will assess mitigations required prior to next flight,” ULA said.

In a statement after launch, Space Launch Delta Commander Brig. Gen. Kristen Leigh Panzenhagen, executive officer of the U.S. Space Force’s Assured Access to Space program, said the service had started its review of Cert-2 performance data.

“We look forward to Vulcan meeting the certification requirements for a range of National Security Space missions,” Panzenhagen said.

In the December time frame, Vulcan is expected to launch USSF-87 for the Space Force and carry two Geosynchronous Space Situational Awareness Program (GSSAP) satellites to orbit, according to the service’s Space Systems Command.

The GSSAP sensors can characterize and inspect objects in geosynchronous Earth orbit to support missions including flight safety, freedom of navigation and on-orbit anomaly resolution. The U.S. military has launched six GSSAP spacecraft since 2014, one of which was deactivated in 2023 after reaching the end of its life span. Two additional space vehicles are scheduled to launch around 2027.

“We designed this rocket for the national security mission space,” Bruno said. “For the industry . . . those launch vehicles are capable of launching at a pretty high tempo, so we have broadened the entire country’s capability for lift.”

Cert-2 followed the successful Jan. 8 Cert-1 test launch with Astrobotic’s Peregrine Mission One lunar lander as the primary payload under a NASA Commercial Lunar Payload Services task order. The launch proceeded successfully, but Peregrine experienced propulsion difficulties of its own that prevented a lunar landing.