In April 2013 Yuzhnoye SDO/Yuzhmash jointly concluded its work on Sea Launch’s Zenit-3SL #SL36 / Intelsat-27 Mission Failure Investigation Board that was held in Dniepropetrovsk.

As was previously reported, the cause of the launch abort was the failure of the onboard power supply (OPS), involved in control of Stage I engines thrust vector.

Having completed series of analyses and experiments to investigate and simulate the possible causes of OPS failure, the joint Yuzhnoye SDO/Yuzhmash Failure Investigation Board released the report. The report states that the most probable cause of OPS failure is jamming of the HPU rotor due to an isolated (originated in the process of manufacturing of the failed OPS) combination of adverse factors that caused a critical decrease of the clearance between the OPS structural elements, resulting in the temperature deformations of such hardware (given in abridged version). Report was coordinated with the experts of the specialized rocket and space institutes and enterprises of the Russian Federation and Ukraine.

Document titled ‘Measures Aimed at Design and Manufacturing Documentation Update to Improve Manufacture Quality and Reliability of OPS’ was released and is being implemented in order to detect and prevent all OPS off-nominal performance causes from all the considered scenarios.

Report and «Measures…» were submitted to Mission Failure Investigation Supervision board (FROB) of ELUS company, which also included representatives of the leading satellite services operators (Intelsat, Eutelsat, SES) and experts of rocket and space industry of the USA. Board members agreed that failure investigation was complete and reason of the OPS failure established and that proper implementation of the developed corrective measures will contribute to the fault-free operation of the Zenit-2S hardware in flight. On June 3 the relevant press release on FROB performance was posted on the Sea Launch web-site.

Recently two Zenit rockets have been modified and re-checked at the Yuzhmash PA facilities and measures specified in “Measures…” have been implemented there in full. Zenit rockets are scheduled to be delivered to the Baikonur Cosmodrome in June for launches planned for III and IV quarters of 2013.

Yuzhnoye Public Relations Center