Orbital Sciences says it will probably stop using the type of engines that were used when the unmanned Antares commercial supply rocket bound for the International Space Station exploded moments after liftoff last week. Orbital Sciences says the investigation of the crash is continuing. Preliminary results point to a failure in one of the two main engines. It still plans to fulfill its contract with NASA to deliver all remaining cargo to the International Space Station by the end of 2016. Orbital Sciences, based in Virginia, says there will be no cost increase for NASA. It doesn't believe the costs related to the accident to be materialized in 2015 either. It will introduce an already-planned upgrade to the Antares propulsion system early in 2016.