Gaia, space observatory, European Space Agency (ESA)

This animation illustrates how Gaia will scan the sky during its all-sky survey.

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Our Galaxy the Milky Way is made up of a hundred billion stars. To truly understand its evolution we need to know exactly where we stand in this mass of constantly moving and changing celestial objects. To do this, astrometry, the science of measuring the position, distance and movement of stars around us, is just about to take a giant leap forward with the launch of ESA's new space telescope, Gaia. Gaia will make it possible to measure a billion stars of our Milky Way.

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Gaia is ESA's billion-star surveyor, designed to provide a precise 3D map of our Milky Way galaxy in order to understand its composition, formation and evolution.

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ESA's Gaia mission will produce an unprecedented 3D map of our Galaxy by mapping, with exquisite precision, the position and motion of a billion stars. The key to this is the billion-pixel camera at the heart of its dual telescope. This animation illustrates how the camera works.

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As the Gaia space telescope prepares to launch, find out how a celestial self-portrait of a billion stars is set to revolutionise astronomy
Read more:

"Ultimate selfie: Space megacamera will map Milky Way"
The Gaia space telescope is preparing to launch, promising a celestial self-portrait of a billion stars that will revolutionise astronomy

by Stuart Clark
December 11, 2013

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Using a billion pixel camera and 2 telescopes, the European spacecraft will scan every star at least 70 times during a 5 year period. This will create the most comprehensive guide to the Milky Way to date. Gaia Probe gallery here: Photos:

"Gaia Spacecraft to Map Milky Way Galaxy"

November 15, 2016

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Animation showing Gaia launch and journey to its operating orbit. The animation begins by visualising the launch from Europe's Spaceport in Kourou, French Guiana, on a Soyuz-STB/Fregat-MT vehicle. The rocket's four boosters are jettisoned 118 seconds after launch, and the spacecraft fairing is jettisoned after 220 seconds. Following two burns, the Fregat upper stage separates from Gaia 42 minutes after launch. The separation activates an automatic sequence onboard Gaia, including switching on the spacecraft's transmitters, pressurisation of the propulsion system, initial attitude acquisition and deployment of the sunshield. By then Gaia will be on its transfer orbit from Earth towards L2, a virtual point in space some 1.5 million kilometres 'behind' Earth as seen from the Sun. Gaia will take about a month to cruise and manoeuvre into a 'Lissajous' orbit around L2. The size of the orbit is typically 340 000 x 90 000 km and takes 180 days. There, Gaia will spin slowly in order to make systematic repeated observations of stars covering the whole sky with its two telescopes. Over its five-year mission, Gaia will monitor the positions, motions, temperatures, luminosities and compositions of a billion stars.

Credit: ESA--C. Carreau/ATG medialab

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Watch a replay of ESA's billion-star surveyor Gaia lift off at 09:12UT/10:12CET on 19 December

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ESA's Gaia mission blasted off on 19 December 2013 on a Soyuz rocket from Europe's Spaceport in Kourou, French Guiana, on its exciting mission to study a billion suns.

Gaia is destined to create the most accurate map yet of the Milky Way. By making accurate measurements of the positions and motions of 1% of the total population of roughly 100 billion stars, it will answer questions about the origin and evolution of our home Galaxy.

The Soyuz launcher, operated by Arianespace, lifted off at 09:12 GMT (10:12 CET). About ten minutes later, after separation of the first three stages, the Fregat upper stage ignited, delivering Gaia into a temporary parking orbit at an altitude of 175 km.

Gaia is now en route towards an orbit around a gravitationally-stable virtual point in space called L2, some 1.5 million kilometres beyond Earth as seen from the Sun.

This video includes highlights of the launch webcast including lift-off from Kourou, the Soyuz mission, separation of Gaia and the successful entry into orbit.

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On 25 April 2018, ESA’s Gaia mission will publish its much awaited second data release, including high-precision measurements of nearly 1.7 billion stars in our Galaxy.

Scientists who have been working on creating and validating the data contained in the catalogue tell us why they are waiting for this extraordinary release.

Featured in the video: Antonella Vallenari (INAF, Astronomical Observatory of Padua), Anthony Brown (Leiden University), Timo Prusti (European Space Agency), Annie Robin (Institut UTINAM, OSU THETA Franche-Comté-Bourgogne), Laurent Eyer (University of Geneva) and Federica Spoto (IMCCE, Observatory of Paris).

A media briefing on the second Gaia data release will be held at the ILA Berlin Air and Space Show in Germany on 25 April 11:00-12:15 CEST.

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Launched in December 2013, ESA’s Gaia satellite has been scanning the sky to perform the most precise stellar census of our Milky Way galaxy, observing more than one billion stars and measuring their positions, distances and motions to unprecedented accuracy.

The second Gaia data release, published in April, has provided scientists with extraordinary data to investigate the formation and evolution of stars in the Galaxy and beyond, giving rise to hundreds of scientific studies that are revolutionising our view of the cosmos.

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