The Gaia space probe, launched in December 2013, has mapped more than a billion stars in the Milky Way, vastly expanding the inventory of known stars in our galaxy, the European Space Agency said Wednesday.

Released to eagerly waiting astronomers around the world, the initial catalogue of 1.15 billion stars is "both the largest and the most accurate full-sky map ever produced," said French astronomer Francois Mignard, a member of the Gaia consortium.