The total number of spacecraft of the GLONASS satellite constellation is 20 including 17 in operation and 3 in process of putting into operation, which takes 45 days after the launch.
To reliably cover the entire territory of Russia the GLONAS System needs at least 18 operating satellites, and to cover the globe – 24.
The GLONASS was commissioned for the Russian Defense Ministry in September 1993. That time its satellite constellation was limited to 12 satellites only. In December 1995 the satellite constellation was increased up to the specified fleet (24 satellites) however later due to lack of funds it again shrunk down to a limited number. In December 2005, Vladimir Putin gave an instruction to RosAviaKosmos and Defense Ministry to speed up the restoration of the GLONASS satellite constellation.