Proton fails again with Ekspress satellite

A Proton rocket failed during the operation of its third stage, leading to the loss of a Russian communications satellite Ekspress-AM4R on May 16, 2014.

Bookmark and Share

Ekspress-AM4R satellite

In December 2011, the Russia's federal satellite communications company, FGUP Kosmicheskaya Svyaz awarded a contract to the European aerospace consortium EADS Astrium (later renamed Airbus Defense and Space) for the development of Ekspress-AM4R and Ekspress-AM7 satellites.

Ekspress-AM4R was designed to replace the Ekspress-AM4 satellite, which was lost during a failed Proton mission in August 2011. The developer based the satellite on its standard Eurostar E3000 platform. The 5,755-kilogram Ekspress-AM4R was equipped with 63 transponders working in C-, Ku-, Ka and L-band. The satellite's 10 antennas were designed to provide communications over the entire Russian territory.

Following the loss of Ekspress-AM4R satellite, a representative of FGUP Kosmicheskaya Svyaz told the official RIA Novosti news agency that it would take three years to replace the spacecraft.

Mission history

It was the 4th mission of the Proton rocket this year and the 11th Russian orbital launch attempt in 2014.

In preparation for this launch, Ekspress-AM4R was delivered to the launch site on February 28. The spacecraft was reportedly ensured for 7.8 billion rubles.

By March 2014, maintenance work at Pad 39 at Site 200 in Baikonur required to postpone the launch of the Ekspress-AM4R from April 6 to around May 16.

Ekspress-AM4R fails to reach orbit

Ground track

A planned ground track of the Proton mission to deliver Ekspress-AM4R satellite on May 16, 2014.

A Proton rocket with Briz-M upper stage lifted off as scheduled on May 16, 2014, at 01:42 Moscow Time, from Pad 39 at Site 200 in Baikonur Cosmodrome. The launch vehicle carried the Ekspress-AM4R communications satellite. According to the Russian space agency, Roskosmos, the anomaly during the firing of the third stage prevented the satellite from reaching orbit. The State Commission overseeing the mission was analyzing the telemetry in the effort to determine the cause of the failure, Roskosmos said.

Under normal circumstances, the third stage should reenter the atmosphere with any surviving debris falling into the Pacific, east of Japan. According to the flight plan, the third stage was programmed to operate until T+582.2 seconds in flight, however according to the official Russian media, it failed around 40 seconds earlier. Several hours after the liftoff, the official ITAR-TASS news agency reported the failure of a steering engine on the third stage 545 seconds after liftoff at an altitude of 161 kilometers over the Chinese territory.

The ITAR-TASS quoted the head of the Russian space agency, Roskosmos, Oleg Ostapenko as saying that the head of the TsNIIMash research institute Aleksandr Danilyuk would be appointed to lead the investigation into the failure.

The drop in pressure was reportedly detected in one of the steering engines as early as 20 seconds before the emergency engine cutoff at T+545 seconds. The steering engine has four combustion chambers and any failure of one of them could lead to a tumbling of the vehicle. According to a posting by a Proton contractor on the web forum, a steering mechanism in the propulsion system of the third stage caused the failure.

Another statement from Roskosmos issued at 10:56 Moscow Time said that preliminary analysis of telemetry indicated that the third stage disintegrated at an altitude of 160 kilometers while flying at a speed of 7 kilometers per second. All components of the vehicle and its propellant burned up in the atmosphere, the agency said. However Chinese media reported falling debris in the northern Heilongjiang Province around the time of the accident.

Failure investigation ends

On Sept. 29, 2014, a day after the Proton successfully returned to flight, the International Launch Services, ILS, which markets Proton rockets to customers outside Russia, announced that the Failure Review Oversight Board, FROB, has concluded its work after a detailed review of the findings by the Russian State Inter-agency Commission, IAC, and GKNPTs Khrunichev into the probable cause of the Proton's failure to deliver Ekspress-AM4R.
The members of the FROB reviewed the initial assessment provided by the IAC along with the additional testing and investigations that the IAC directed to be performed by Khrunichev and their subsidiaries. Based on the data presented, it was agreed by the FROB that the probable cause of the failure was the loss of structural integrity of a bolted interface that attaches the Stage III steering engine turbopump to the main engine structural frame. The loss of integrity led to an excessive steering engine turbo pump vibration environment that damaged a fuel inlet line to the oxidizer gas generator, resulting in a fuel leak. The loss of fuel led to the premature shutdown of the turbopump and loss of stage control authority and ultimately loss of mission approximately 545 seconds into the flight.

Additionally, the FROB concurs that the identified corrective action plan will adequately address the identified probable cause and contributors to the failure, ILS said.

According to ILS, all of the required corrective actions were incorporated into the Proton's return-to-flight mission.



Bookmark and Share

This page is maintained by Anatoly Zak

Last update: December 15, 2021

All rights reserved


insider content



Ekspress-AM4R during pre-launch processing. Credit: Roskosmos


A Proton rocket with Ekspress-AM4R satellite shortly after its rollout to the launch pad on May 13, 2014. Credit: Roskosmos


Proton begins an ill-fated mission on May 16, 2014. Credit: Roskosmos