Ground testing anomaly destroys Firefly Aerospace’s Alpha booster intended for next flight

Firefly Aerospace suffered a setback on its road to resuming launches with its Alpha rocket.

During acceptance testing at its facility in Briggs, Texas, on Monday, the booster designated for Alpha Flight 7 “experienced an event that resulted in a loss of the stage,” the company said in a statement.

A spokesperson for Firefly said this acceptance test was taking place prior to the company shipping the booster to Vandenberg Space Force Base ahead of conducting a final static fire test and preparing for launch.

A week before the incident, during the company’s second quarter earnings call on Sept. 22, CEO Jason Kim said he expected Firefly to resume launches in the “coming weeks” following a pause stemming from an in-flight anomaly seen during Alpha Flight 6 back in April.

“We received our [Federal Aviation Administration] Return to Flight determination at the end of August. We expect to launch Flight 7 in the coming weeks,” Kim said during the call in response to Jeffries analyst Shelia Kahyaoglu. “If you saw our slides in the Alpha slide, you can see that Flight 7 is in a mature state, right next to Flight 8 in a mature state.

“And so we keep increasing our production capacity and we’re building ahead as well for 2026. So we’re working closely with the range and our customer, Lockheed Martin, to share more details on the mission and payload soon. But above all, safety and quality are the highest importance.”

An investigation into Alpha Flight 6 with oversight from the FAA and in parallel with an independent review board determined that the April anomaly was due to “plume-induced flow separation intensified heat on the leeward side reducing structural margins, causing the booster to rupture from stage separation induced loads.”

Firefly noted in a statement last month that it would “increase the thermal protection system thickness on Stage 1 and reduce angle of attack during key phases of the flight,” which it said had been implemented as of issuing that statement on Aug. 26.

In response to questions from Morgan Stanley analyst Kristine Liwag during the earnings call, Kim said the corrective actions didn’t require a change to the design of Alpha.

“There is no change to the design. It’s just adding more layers of the thermal protection system to the bottom of the first stage, and it’s negligible in terms of mass,” Kim said. “The second part of that question is, how does this change the angle of attack? We can control that at different phase, critical phases of the flight profile. And so that is something that we can plan for and can control as well.”

Alpha Flight 6 and Flight 7 are both part of a multi-launch contract between Firefly and Lockheed Martin, which would be up to 25 missions. The payload for Flight 7 hadn’t been announced before the anomaly occurred.

During testing at Firefly Aerospace’s facilities in Briggs, TX, an Alpha booster designated for Flight 7 exploded on the test stand. Firefly reports there were no injuries, but the booster was lost. A security camera at nearby Harold’s Auto Parts captured the incident. pic.twitter.com/ZcJguqWtY1

— Spaceflight Now (@SpaceflightNow) September 29, 2025

Mixed record

The history of the Alpha rocket has been somewhat of a mixed bag for Firefly. It’s first launch was back in September 2021 with the mission name “Dream.” That rocket failed to reach orbit due to an engine cutting off prematurely thanks to “an electrical short to one of the valves.”

More than a year later, in October 2022, Firefly returned to the pad with Flight 2: “To the Black.” The team was able to successfully deploy three demonstration satellites, including the aptly named Serenity, likely a nod to the main spaceship seen in the sci-fi show called “Firefly.”

The win streak continued less than a year later in September 2023 when Firefly successfully launched the U.S. Space Force’s Victus Nox mission, deploying a satellite from Millennium Space Systems.

However, during Flight 4, also known as “Fly the Lightning,” Firefly saw a guidance, navigation and control (GNC) issue on the rocket’s second stage that prevented it from achieving its planned orbit. Flight 5, “Noise of Summer,” fared much better with the successful launch and deployment of eight CubeSats as part of its Venture-Class Launch Services Demo 2 contract with NASA.

Prior to the unsuccessful Flight 6 mission in April, Firefly achieved the first, fully successful landing by a commercial company on the Moon during Blue Ghost Mission 1. That mission proved so fruitful in fact, that NASA added a $10 million contract to acquire more imagery and data received from the lander beyond the original contract.

Firefly has three more Blue Ghost missions lined up as part of NASA’s Commercial Lunar Payload Services Program and is also working towards the rollout of its Elytra spacecraft, designed for in-space maneuverability and multiple mission manifests.

Looking to the future

While it’s working towards the Return to Flight launch of Alpha, Firefly is also developing the Eclipse rocket with Northrop Grumman, formerly known as the Medium Lift Vehicle or MLV. Kim said Firefly is pressing towards the first Eclipse launch in “the late 2026 timeframe.”

“We built in fit check the first stage tanks for Eclipse’s debut flight, and we’ve begun structural and load testing of the engine bay that will house our seven Miranda engines,” Kim said. “These powerful Miranda engines are progressing through our rigorous test campaign, with more than 90 hot fire tests completed to date, including full power and mission duty cycle firings.”

Meanwhile, it’s unclear how long Alpha may need to remain grounded before Flight 7 can take place.

“We learn from each test to improve our designs and build a more reliable system,” Firefly wrote. “We will share more information on the path forward at a later date.”