<span style="color: #222222;">NASA's legendary Kepler space telescope has retired after running out of fuel needed for further science operations. The US space agency said this brings an end to a prolific nine-and-a-half year mission in which it discovered over 2,600 intriguing exoplanets, some of which may harbour life.</span><br />” <br />” <span style="color: #222222;">In a statement, NASA said data collected from Kepler's deep space missions indicates our sky is filled with billions of hidden planets – more than the stars. The US space agency said the unmanned space telescope, which launched in 2009, leaves a legacy of more than 2,600 planet discoveries from outside our solar system, many of which could be promising places for life.</span><br />” <br />” <span style="color: #222222;">NASA's Science Mission Directorate in Washington said as NASA's first planet-hunting mission, Kepler has wildly exceeded all expectations and paved the way for exploration and search for life in the solar system and beyond.</span><br />” &nbsp;