ESA Launch preparations begin for Gaia galaxy-mapper

Artist's concept of the Gaia spacecraft. 

Credit: ESA/ ATG medialab; background image: ESO/S. Brunier

Europe’s new eye on the galaxy arrived in French Guiana on Friday, beginning three months of flight preparations before liftoff on a Soyuz rocket in November to commence a survey of a billion stars and chart their chaotic motion in the Milky Way galaxy.

The Gaia observatory will be stationed a million miles from Earth, its dual telescopes sweeping across the sky with the sensitivity to plot the exact locations and movements of stars, detect the signatures of alien worlds, and spot icy dwarf planets on the outer frontier of the solar system.

The breadth of Gaia’s scientific promise ranges from scanning the Milky Way to create a three-dimensional map of the galaxy to the discovery of asteroids in Earth's neighborhood.

Scientists say Gaia could return data leading to the discovery of up to 2,000 planets around other stars – mostly Jupiter-sized gas giants.

And the European space mission has the precision to test tenets of Albert Einstein’s theory of general relativity by observing how the pull of the sun and planets bend starlight before it reaches Gaia’s apertures.

In five years, Gaia will collect a petabyte of data, enough to fill 1.5 million compact discs. It will see a billion stars, more than ever observed by any other mission, and use information about those objects to study the origin and evolution of the Milky Way.

“The estimate of the number of stars in the Milky Way is between 100 and 200 billion stars, so we observe between one-half and one percent of these stars,” said Timo Prusti, Gaia’s project scientist at the European Space Agency.

“Because of the completeness of Gaia to a limiting magnitude, this proving of 1 percent of these objects will help us reconstruct the remaining part. We’re not going to take a full census of the Milky Way, but we are going to look at a billion stars and we’ll have enough statistical power to deduce the structure of the Milky Way.”

A team of scientists and engineers has worked on Gaia since the mission was approved by the European Space Agency in 2000. The mission’s cost is 740 million euros, or approximately $990 million.

After of 13 years of development, design reviews, construction and testing, Gaia is one step closer to the launch pad.

Liftoff is scheduled for Nov. 20 at 0857 GMT (3:57 a.m. EST; 5:57 a.m. local time) aboard a Europeanized version of Russia’s Soyuz rocket.

The mission will mark the seventh flight of a Soyuz booster from French Guiana, and a Fregat upper stage will propel Gaia on a trajectory toward the L2 Lagrange point about a million miles from the night side of Earth, where gravity from the Earth and sun balance a satellite’s motion.