The European Space Agency say preparations are complete for a billion-star survey spacecraft ready to depart for its launch site in French Guiana.

The main goal of the Gaia space telescope during a five-year mission is to create a highly accurate 3D map of our Milky Way Galaxy by repeatedly observing a billion stars to determine their precise positions in space and their motions through it, a release from the Paris headquarters of ESA said Thursday.

The result of this cosmic census will allow astronomers to determine the origin and the evolution of our galaxy, researchers said.

"Gaia will be ESA's discovery machine," Alvaro Gimenez, the agency's director of science and robotic exploration, said.

"It will tell us what our home galaxy is made of and how it was put together in greater detail than ever before, putting Europe at the forefront of precision astronomy."

Gaia will be launched this year on an Arianespace Soyuz rocket from Europe's Spaceport in Kourou, French Guiana, and will map the stars from an orbit around the sun at a distance of almost a million miles beyond Earth's orbit.