Russia grounds Proton-M rocket for 3 months

Deputy Russian Prime Minister Dmitry Rogozin says that Proton-M rockets will be out of service for three and a half months because of engine problems.

Rogozin announced the delay on Twitter on Saturday following a visit to the factory where the engines are manufactured.

He says employees at the factory had been involved in faking documentation linked to the rocket and pledged that those responsible would be "harshly punished."

He told journalists that: "It's lucky that it didn't end in an accident."

The Proton-M rockets, a workhorse of the Russian space program, are used for deliveries to the International Space Station

Russian rockets have suffered several serious accidents in recent years. In May 2014, a Proton-M rocket carrying an advanced satellite broke up shortly after launch.