|Launch vehicle||Falcon 1|
|Launch site||Kwajalein Atoll, Marshall Islands|
|Date/Time||2006-04-24 22:30 UTC|
|Description||First stage failure|
|Cause||Corroded aluminium nut|
|Desired orbit||400 km x 500 km x 39 degrees|
A corroded nut that allowed fuel to leak onto the main engine caused the Falcon 1 launch failure, a U.S. government board concluded. The leaked fuel caught fire and caused the rocket to fail 34 seconds after lift-off.
The board determined that the only plausible cause of the fire was the failure of an aluminium B-nut on the fuel pump inlet pressure transducer due to inter-granular corrosion cracking. This nut allowed RP-1 fuel to leak onto the engine and down the outside of the thrust chamber. Once the engine ignited, the leaking fuel caught fire. The fire, over time, resulted in a loss of pneumatic pressure, causing the RP-1 and liquid oxygen pre-valves to close, terminating engine thrust 34 seconds after ignition.
The board's determination was based on the analysis of recovered parts immediately adjacent to the failed B-nut, telemetry that showed lower than expected pressure in the fuel line near the failed B-nut (evidence of a fuel leak in that particular location), and pre-launch fuel checks that verified the integrity of the rest of the fuel system
SpaceX had initially suspected that the Falcon 1's fuel leak was caused by a pipe fitting loosened and accidentally left that way by technicians doing work on the rocket the day before launch.