NEW DELHI: With the successful launch of “eye in the sky” Cartosat-2E satellite with surveillance capabilities last Friday, the total number of satellites being used for military purpose has gone up to 13, an Isro source said.

These satellites, which can be used for surveillance and mapping border areas, are primarily used for keeping an eye on enemies both on land and sea .

“Most of these remote-sensing satellites are placed in the near-earth orbit. Placing these satellites at the sun-synchronous polar orbit (about 200-1,200 km above the Earth’s surface) helps in better scanning of the earth. However, some of these satellites have also been put in the geo orbit,” the source said. The recently launched 712-kg Cartosat-2 series spacecraft is an advanced remote sensing satellite capable of providing scene-specific spot imagery.

The Cartosat-2 can accurately spot objects within a square of 0.6 metre by 0.6 metres.

“The 13 satellites used by the military for surveillance include Cartosat 1 and 2 series and Risat-1 and Risat-2 ,” the Isro source said.