Expedition Aerospace’s new Endurance rocket lifted off on its debut flight from Space Launch Complex 576E this past Saturday, marking the company’s first attempt at orbit with its in house launch vehicle.

 

But just under two and a half minutes into flight, the mission ended in failure following a series of engine anomalies that led to a loss of control and the eventual destruction of the rocket.

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The vehicle, designated FS001, lifted off cleanly from the Vandenberg pad at its scheduled time, with all engines performing nominally in the first seconds of flight. However, the first signs of trouble began almost immediately at T+10 seconds, one of the rocket’s engines, numbered E4, shut down due to what would later be confirmed as a fuel leak inside the liquid oxygen tank. That leak led to a fire in the engine bay that burned unchecked throughout ascent.

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Despite the early loss, Endurance continued climbing as planned, until the fire intensified enough to disable two more engines, E3 at T+1:56 and E2 at T+2:19. A fourth engine failed just two seconds later, with all four affected engines located on the same side of the first stage.

 

The resulting asymmetric thrust quickly overwhelmed the rocket’s control authority systems, and the vehicle entered a tumble just seconds before main engine cutoff.

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Telemetry was lost approximately 20 seconds later, confirming the end of the mission.

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While the loss of the vehicle was disappointing, Expedition Aerospace emphasised the flight’s successes including a largely intact pad and ground system and the amount of data gained.

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“We learned a bunch of data from this launch,” said Kadobe, founder and CEO of Expedition Aerospace. “Not much needs to change except the engine bay and fuel lines.”

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According to follow up statements from the company, Endurance's onboard systems attempted to proceed with stage separation, but the flight computer denied the command due to the tumbling motion.

 

The stage separation springs, the system that deploy the upper stage, never activated.

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“Endurance performed amazingly,” Kadobe said. “But due to the tumble, the flight computer denied the activation of the stage separation springs.”

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The failure appears localised to one side of the engine bay, and was not mitigated by fire containment systems, both of which will see upgrades ahead of the next flight. In particular, the company confirmed it is improving the fire suppression system in the first stage to mitigate the risk of recurring engine bay fires.

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Despite the failed outcome, the company praised the performance of its launch infrastructure. The strongback and pad systems functioned nominally, and inspections revealed little to no damage to the launch site.

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Expedition Aerospace announced that it would conduct a mishap investigation in cooperation with Roblox Aviation Administration and Technology Corporation, reviewing both vehicle performance and pad safety protocols.

 

Preliminary findings suggest that the initial engine fire was survivable, and possibly fixable mid flight had the following failures not followed.

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A second flight of Endurance, using vehicle FS002, is already in preparation and currently undergoing system testing.

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“If all goes well,” Expedition Aerospace stated, “we could see a launch in late September.”

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While the vehicle did not reach its target of stage separation and orbit, Expedition Aerospace is focused on iteration and continued flight testing, confident that the lessons from FS001 will lay the foundation for future success.