Russian Angara-5A heavy-lift rocket 

The engines of Russia’s new flagship heavy-lift space rocket, Angara A5, have a defect that can ultimately destroy the rocket itself, according to a paper published by scientists at rocket engine manufacturer Energomash.

The paper, reported by RIA news agency on Friday,said the engines of the Angara A5 could produce low frequency oscillations that could ultimately destroy the rocket, Japan Times reported Saturday.

The Angara A5, which was test-launched in 2014, is being developed to replace the Proton M as Russia’s heavy-lift rocket, capable of carrying payloads bigger than 20 tons into orbit. A launch pad for the new rocket is due to open in 2021.

A special valve had been fitted to mitigate the issue, but in some cases the oscillations continued, it said.

Russia’s space program has been dogged by mishaps in recent years, including failed cargo delivery missions into space and the aborted launch in October of the manned Soyuz mission to the International Space Station.

Russia’s current heavy-lift rocket, the Proton M, has had a nearly 10 percent failure rate in more than 100 launches since it entered service in 2001, creating pressure to reorganise and improve the space program.