ESA's billion star-hunter telescope enters orbit

Europe's billion-star hunting telescope has successfully entered its operational orbit to gather data for the most accurate 3D map yet of our Milky Way galaxy, the European Space Agency (ESA) said.
ESA's star surveyor Gaia is now in its operational orbit around a gravitationally stable virtual point in space called 'L2', 1.5 million km from Earth.
Gaia has been travelling towards L2 since December 19, when it was spectacularly launched from ESA's Spaceport in Kourou, French Guiana.
A day later, Gaia performed an important thruster burn to set course to its destination. A critical manoeuvre boosted Gaia into its 180 day-long orbit around L2. A small course correction will be made next week to complete the manoeuvre.

"Entering orbit around L2 is a rather complex endeavour, achieved by firing Gaia's thrusters in such a way as to push the spacecraft in the desired direction whilst keeping the Sun away from the delicate science instruments," said David Milligan, Gaia spacecraft operations manager.
"After a beautiful launch from Kourou last month, we are very happy to now have reached our destination, and we are looking forward to starting our science operations in the coming months," said Giuseppe Sarri, ESA's Gaia project manager.

Once the spacecraft instruments have been fully tested and calibrated - an activity that started en route to L2 and will continue for another four months - Gaia will be ready to enter a five-year operational phase.

Gaia will make very accurate observations of one billion stars, charting their precise positions and motions, as well as their temperatures, luminosities and compositions.
This enormous census will result in the most accurate 3D map yet of the Milky Way and allow astronomers to determine the origin and the evolution of our galaxy, ESA said.
To achieve its goal, Gaia will spin slowly, sweeping its two telescopes across the entire sky and focusing their light simultaneously onto a single digital camera - the largest ever flown in space with nearly a billion pixels.
Gaia will observe each star an average of 70 times over the five-year mission, after which the data archive will exceed one million Gigabytes, equivalent to about 200 000 DVDs' worth of data.