Russia has launched a satellite needed to create its own global navigation system, intended to rival America's Global Positioning System (GPS).
The Glonass-K satellite was carried into orbit on a Soyuz rocket from a cosmodrome in northern Russia.
In December, an attempt to put the final three satellites into space failed when they crashed into the sea.
More launches are planned with the aim of finishing the system this year.
The Russian prime minister, Vladimir Putin, has said the Glonass system will give the country satellite navigation sovereignty.
The BBC's Sean Fanning says that, for commercial and military reasons, Russia does not want to be dependent on America's GPS, which can theoretically be switched off at any time.
This latest launch brings Russia close to the 24 operational satellites it needs for Glonass to cover the entire globe, our reporter says.
Russia had already successfully launched a number of the Glonass satellites last year and had hoped to have the system finished by 2011.
However, the rocket carrying the three satellites needed to complete it veered off course in December after being launched from the Baikonur cosmodrome in Kazakhstan.
Russian aerospace experts said the Glonass spacecraft and the upper-stage booster carrying them probably fell into the Pacific Ocean near Hawaii.
- 29 December 2010
- 5 December 2010