Kuznetsov company says engines used in Antares rocket were ‘functioning normally’ and suggests problem may lie with US modification of them

The launch phase of the Orbital Sciences Corporation’s Antares rocket relied on two AJ-26 engines that were originally produced in the 1970s for a failed Soviet moon program and later modernised for US space flights. Speculation quickly centered on the Soviet-based engines, which have failed in tests, when the rocket exploded in a giant fireball after takeoff on Tuesday night.