MOSCOW, August 4. /TASS/. The international commission investigating the causes of the Proton-M carrier rocket crash with Mexica’s MexSat-1 (Centenario) satellite has competed its work, the International Launch Services (ILS) said in a release posted on its website on Tuesday.
The commission has found, the same as Russia’s Federal Space Agency Roscosmos, that the crash was caused by a design flaw of the third stage’s turbo pump rotor shaft that failed due to high vibration.
"The International Launch Services (ILS) Failure Review Oversight Board (FROB) concluded its work, concurring with the most probable cause and the associated corrective action plan which were identified by the Russian Interagency Commission (IAC) as a result of the May 16 Proton launch vehicle failure carrying the Centenario spacecraft," the release says. "The members of the FROB reviewed the findings and conclusions from the IAC along with results from testing and investigations that the IAC directed to be performed by Khrunichev and their subsidiaries."
"Based on the data presented by KhSC, the FROB agreed that the most probable cause of the failure was a result of a higher than expected vibration environment most likely caused by the combination of a marginal mechanical joint used to mount the Stage III steering engine turbo pump and a steering engine turbo pump rotor material that had marginal strength under maximum operating environments. This led to a premature shutdown of the turbo pump and loss of Stage III control authority and subsequently to the failure of the mission during 3rd stage operation approximately 497 seconds after liftoff," says the ILS release.
"The participating customers, insurance underwriters and independent subject matter experts are to be commended for their valuable contributions during the extensive FROB review process. We thank our customers for their support as we prepare for the safe return to flight of ILS Proton," said ILS Vice President and Chief Technical Officer, John Palme.
According to previous reports, Proton launches were suspended pending the completion of the investigation into the causes of the crash of the Proton-M carrier rocket with the Mexican communications satellite MexSat-1, which occurred on May 16, exactly one year after a similar accident. Roscosmos came to the conclusion that the carrier rocket was lost because of a design flaw that caused Proton’s failure back in 1988.
The first after the crash launch of the Proton-M rocket is planned to be carried out from the Baikonur cosmodrome on August 28 to orbit the UK communications satellite Inmarsat-5FZ.
ILS provides marketing services or the Proton rocket launches in the international market. ILS is a world leader in providing launch services for global satellite operators and offers a complete array of services and support, from contract signing through mission management and on-orbit delivery. ILS has exclusive rights to market Proton launch services for commercial and civil satellite programs world-wide. The commercial Proton is ILS Proton. The company is owned by Russia’s Khrunichev State Research and Production Space Centre - the designer and manufacturer of the Proton-M rockets.