Russia grounds Proton-M rocket for 3 1/2 months

MOSCOW (AP) — Russia's workhorse Proton-M rockets will be out of service for three and a half months because of engine problems, Deputy Prime Minister Dmitry Rogozin said Saturday during a visit to the factory in the city of Voronezh where the engines are manufactured.

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

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

The Proton-M rocket, a stalwart of the Russian space program, is used primarily for military and commercial satellite launches.

The head of the Voronezh factory resigned last week after Russian officials said the crash of a Progress cargo ship in December was the result of a malfunction by engines built at the plant.

The accident is one of several serious incidents to hit Russia's space industry in recent years. A Progress cargo ship plunged into the Pacific Ocean in May 2015, and a Proton-M rocket carrying an advanced satellite broke up in the atmosphere shortly after launch in May 2014.