Russia’s Krunichev Space Centre has established that a welding defect in the number three engine of the rocket’s second stage was the cause of the failure of the Raguda launch failure on July 5.

International Launch Services, responsible for the launch, issued a statement quoting Krunichev director general Anatoli Kiselev, who told the Russian newspaper Izvestia that "the fire was started by a stray aluminium particle in a seam between the cover and the apparatus as a result of a defect in the weld. Such stray particles may enter the apparatus from the fueling equipment through personnel neglect or can be blown in by a turbo pump." Kiselev said the investigating sub-commission’s findings would be completed following detailed examination of the fifth ‘control’ engine on the ground at Voronezh. He said the turbopump design would be upgraded and a filter installed to protect from fire caused by stray particles. He added that the accident had also led Krunichev to bring forward the upgrade, together with one on the fuelling equipment, from 2000. However, the failure was the result of "a single manufacturing failure", he said. The engines were designed by the Khimavotmatika Design Bureau and manufactured by Voronezh Mechanical Engineering Works.

Kiselev, together with Russian deputy prime minister Ilya Klebanov and Russian Space Agency head Yuri Koptiev visited Kazakhstan at the end of last month to discuss the lifting of the current moratorium on Proton launches, imposed by the Kazakh government after the accident. Debris from the Proton rocket’s third stage along with the Breeze M upper stage and the spacecraft payload fell in the Karaganda region of the country, about 1,000 km from the launch site, after the vehicle deviated from its planned trajectory some 280 seconds into its flight. One of the first commercial casualties of the failure was the planned July 30 launch of Eutelsat’s Sesat satellite, destined to bolster its presence at the burgeoning 36 degrees East slot.