"Revision is necessary, as well as conducting additional tests of the control system of the upper stage," Roscosmos said, specifying that the new date of the launch would be announced later.
The launch of Proton-M carrier rocket with European Eutelsat 5 West B telecommunications satellite and US Mission Extension Vehicle-1 was due to take place on September 30.
The Proton-M is the largest carrier rocket in Russia's fleet of space launch vehicles. The rocket has lifted dozens of Russian-made and foreign satellites into orbit since it was first commissioned in 2001.
