India is moving closer to having its own satellite navigation system as preparations are underway for the launch of the fourth satellite this week.

An Indian navy surveillance aircraft crashed into the sea off the coast of the western state of Goa on March 24, the latest in a series of deadly disasters for the country’s military.

India’s first Mars mission has successfully completed six months in space and is expected to stay in orbit for another six months to explore the red planet and its atmosphere.