PARIS –
A Russian government board of inquiry has concluded that the March failure of a
Proton-M rocket was caused by unexpected high temperatures in one of the upper-stage engine’s pipes, which combined with an unpredicted level of pipe bending during the launch to rupture the pipe and force the engine’s premature shutdown, International Launch Services (ILS) President Frank McKenna said April 25.
The March 15 failure of the Breeze-M upper stage placed the SES Americom AMC-14 satellite in a useless orbit. Luxembourg-based SES has since declared the satellite a total loss. SES and
its customer, EchoStar Corp. of Englewood, Colo., had insured the satellite for $192 million.
McLean, Va.-based ILS is the commercial marketing arm for Proton rockets, which are built by Khrunichev Space Center of Moscow. In an interview, McKenna said the AMC-14 failure was unrelated to a February 2006 Breeze-M failure that left the Arabsat 4A satellite in a similarly useless orbit.
Arabsat 4A
eventually was deorbited.
“These are not the same failure modes at all,” McKenna said. “The Arabsat failure was from a clogged valve in the oxidizer system. A foreign object in a valve caused that failure, so this is not a repeat. This is a different set of circumstances.”
The Russian space agency, Roskosmos, announced following the launch that the Breeze-M stage shut down 32 minutes into its second burn, which is designed to last for 34 minutes and 26 seconds.
ILS announced April 21 that a Russian inquiry will be followed by an ILS-managed Failure Review Oversight Board made up of ILS personnel as well as representatives of ILS customers and insurance underwriters.
McKenna said this oversight group has received the various U.S. and Russian government security clearances and has begun meeting in Moscow with Khrunichev officials to take a second look at what happened.
According to
the Russian government board of inquiry, the AMC-14 launch failed when a gas duct ruptured under the stress of long-term exposure to high temperatures combined with the fact that, during the 32 minutes of ignition, it was oscillating in a way that left it further exposed to temperature-induced rupture.
“The temperatures were higher than expected,” McKenna said. “They were within range, but higher than expected.”
McKenna declined to specify exactly what corrective action has been prescribed to Khrunichev by the Russian investigation. He specifically declined to address whether the gas duct that failed had been qualified through ground testing to withstand prolonged high-temperature environment associated with long burns of the Breeze-M engine. He would not say whether a redesign of the duct was being ordered, saying the inquiry’s recommendations have not been made public.
A long, continuous burn of the upper stage is viewed as optimal for larger telecommunications satellites. If Khrunichev and Proton are obliged to limit their launches to multiple, shorter-duration burns, the rocket may be less able to lift the heaviest satellites that have become ILS’s core market.
ILS and Khrunichev have instituted
a broad quality-assurance program that has been accelerated as a result of the March failure. In particular, a Khrunichev Quality Management System will be put into place with clear authority over the company’s
subsidiaries, including Khimmash, the builder of the Breeze-M upper stage.
Under the direction of the Russian government, Khrunichev has been gradually assuming control of Proton suppliers that for decades had been separate companies.
“This is a broad-based initiative and not just focused on the specific issues related to the AMC-14 Proton Breeze-M failure,” Khrunichev General Director Vladimir Nestorov said in an April 24 statement issued with ILS on the new quality initiative.
While the Russian government uses the Proton vehicle for its own launches, the Proton launch manifest for the next few months is mainly ILS missions, for Inmarsat of London, Telesat Canada and another SES satellite.
McKenna said he is well aware that none of these established satellite-fleet operators is likely to accept anything but clear answers to what went wrong and what is being done to correct it. He said he hoped the ILS review will be completed by late May or early June. Until then, he said, no return-to-flight estimates can be made.
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