BBC News - Kepler telescope bags huge haul of planets: 
"The Kepler space telescope was launched in 2009 on a $600m (£360m) mission to assess the likely population of Earth-sized planets in our Milky Way Galaxy.
Faulty pointing mechanisms eventually blunted its abilities last year, but not before it had identified thousands of possible, or "candidate", worlds in a patch of sky in the constellations Cygnus and Lyra.
It did this by looking for transits - the periodic dips in light that occur when planets move across the faces of stars.
Launched in 2009, the Kepler space telescope sought to find Earth-like worlds orbiting distant stars in the Constellation Lyra
It used the so-called transit technique - looking for the periodic dips in light as exoplanets pass in front of their host stars
Last year, astronomers used Kepler's data to estimate that one in five stars like the Sun hosts an Earth-sized world
How does the Kepler telescope work?
How rare is our blue planet?
Before Wednesday, the Kepler spacecraft had confirmed the existence of 246 exoplanets. It has now pushed this number up to 961. That is more than half of all the discoveries made in the field over the past 20 years."