Russia's space chief says the head of the country's leading rocket manufacturer has stepped down after a failed launch.

A Proton booster rocket failed to place two communications satellites into target orbits after its launch last week, one of several similar mishaps in recent months. Roskosmos director Vladimir Popovkin said Thursday that Vladimir Nesterov, the head of the state-controlled Khrunichev company that builds Proton rockets, submitted his resignation.

Prime Minister Dmitry Medvedev said Tuesday that Russia had seven failed launches in the past 1 1/2 years, resulting in the loss of 10 satellites. He added the high rate of failure marked a "colossal difference with other leading space powers."

Russia's space officials have blamed the failures on manufacturing flaws and engineering mistakes.