The U.S. Federal Aviation Administration (FAA) has cleared Firefly Aerospace to resume launches of its Alpha rocket.
The approval follows a months-long review of the failed “Message in a Booster” mission in April, during which the rocket’s first stage broke apart moments after separation and compromised the vehicle’s second stage. The closure of the investigation, which was announced on Aug. 26, clears the way for Firefly to resume Alpha launches, the preparations for which the company says have already begun.
Alpha’s launch on April 29 — its sixth ever — began nominally. The two-stage, 96.7-foot-tall (29.6 meters) rocket lifted off from California’s Vandenberg Space Force Base and climbed smoothly through first-stage ascent. Shortly after separation, however, a rupture in the booster damaged the engine nozzle on Alpha’s second stage, sharply reducing its thrust capabilities.
Both stages reentered over the Pacific Ocean, splashing down near Antarctica in a pre-cleared safety zone, and did not create a public danger.
The anomaly resulted in the loss of the payload, Lockheed Martin’s LM 400 satellite technology demonstrator, which was supposed to go to low Earth orbit.
The FAA oversaw the review alongside Firefly, with additional support from a board of outside experts from government, industry and the company’s customers. The investigation concluded that extreme heat from a phenomenon known as plume-induced flow separation over-taxed portions of Alpha’s first stage, which suffered a structural break as a result.
Investigators determined the heat buildup from the plume-induced flow separation was exacerbated by Alpha’s steeper ascent angle compared to previous launches, which was needed for proper payload delivery on this mission. The combination caused the stage to rupture milliseconds after separation, which destroyed the nozzle extension on the second-stage engine.
The disruption drastically reduced the rocket’s thrust, but it wasn’t quite cause enough for immediate flight termination. The second stage was able to regain attitude control and managed to climb to a peak altitude of 198 miles (320 kilometers) before exhausting its fuel. Alpha was just three seconds short of reaching orbital velocity, and five seconds shy of its payload’s intended orbit, according to Firefly.
To prevent similar problems during future launches, Firefly will reinforce the first stage’s thermal protection system and adjust flight profiles to avoid similar ascent trajectory stresses to reduce heat buildup.
Company leaders emphasized that the changes should improve Alpha’s resilience and reliability going forward. “Technical challenges aren’t roadblocks — they’re catalysts,” said Alpha Chief Engineer Jordi Paredes Garcia in the release.
“Following all the lessons learned and corrective actions implemented, we were able to further increase Alpha’s reliability. We are grateful to the FAA, our customers, and the independent review board for their continued support through this process,” Garcia said.
With the investigation closed and modifications in place, Firefly says it is turning its attention to Alpha Flight 7. That mission will be the company’s next chance to demonstrate the rocket’s progress as it works to establish Alpha as a competitor in the small-satellite launch market.