Roscosmos has issued a preliminary statement about the the cause of the failure of the 16 May Proton launch, which was carrying the Centenario satellite.
The Proton launcher is due to carry the third Inmarsat I-5 satellite for its upcoming GX Ka-band service into orbit.
This Inmarsat launch was due to occur in June, but the break-up of the Proton over Kazakhstan on 16 May has resulted in an indeterminate hold.
According to the Roscosmos statement, the Russian State Commission concluded that the mission anomaly was traced to a failure of the stage three steering engine due to increased vibration loads.
Under the direction of Roscosmos head Igor Komarov, it says Khrunichev and its subsidiaries are developing an action plan to address the most probable causes of the anomaly to include:
• Changing materials used for the turbo pump rotor shaft manufacturing;
• Revision of the turbo pump rotor balancing techniques;
• Upgrade of the steering engine turbo pump mount to the main engine frame, and others.
ILS will conduct a Failure Review Oversight Board (FROB) to review the findings from the Russian State Commission.
The FROB will include representation from ILS, customers, insurers and technical experts from industry. The FROB will provide an independent review of the investigation, root cause and corrective actions required prior to return to commercial flight.
The FROB will likely commence in late June or early July, once a formal summary of the Russian State Commission’s findings has been released to ILS and Khrunichev completes the development of the action plan to address the most probable causes, as noted above.
The preliminary statement noted that the action plan will be developed within one month.
After the conclusion of the FROB, the FROB report will be briefed to ILS customers and the launch insurance industry.
It says additional information will be provided as it becomes available.
This means no new launch date for I-5 F3 has been set.