Orbital announced today that the preliminary findings of the Accident Investigation Board (AIB) point to a Turbo pump failure in one of the two AJ26 main engines on the Antares rocket.
Because of this Orbital will no longer use the AJ26 engines and will instead accelerate the migration to a new engine on the Antares. Due to the delay in completing the migration, and due to the design on Cygnus, Orbital will use an alternative launcher (to be announced) to fulfill Cygnus missions until such time that Antares is ready. Orbital will assume any additional costs for using the alternate launcher .
Orbital will continue to use Wallops for the upgraded launcher once is it ready and will fulfill any remaining flights in it’s current CRS contract with the modified Antares.
The full press release can be found here.