One of the most widely used space rockets in history, the Russian Proton, made it's 300th launch on June 6th. Originally designed as an ICBM in the 1960s, but never used that way, the Proton proved better at launching satellites. Current Protons cost nearly $60 million to build and launch. Overall, 88 percent of Proton launches have been successful, although the success rate has been higher in the past few years. There are ten Proton launches scheduled for this year. By the end of the decade, Proton will be history.  Proton's owner, Khrunichev State Research and Production Space Center, is developing a new, and cheaper, heavyweight rocket, the Angara. This rocket is expected to enter service by 2006. The Proton comes in three and four stage versions and can launch up to 20 tons into a 200 kilometer high orbit. The most used launcher is the Russian R-7 (Soyuz), which has launched over 1600 times.