Gaia’s Trip Across the Milky Way

On December 19, 2013 at the Guiana Space Centre, the ESA launched Gaia, a 32-foot satellite destined to trek 1 million miles of uncharted territory in space while surveying more than a billion stars.  Nearly a month after its launch, Gaia arrived at the second Lagrangian (L2) where it could continue its mission—to assemble a digital map of our home galaxy, the Milky Way.  For the next five years, Gaia will scan the Milky Way, making about 40 million observations each day.

Before Gaia started scanning the stars, the satellite had to go through a set of procedures to test its programs.  Putting together a map of an entire galaxy is not an easy task, so the Kourou Project Team must confirm that all systems run smoothly by finding and fixing any issues.  In February, the team found that external sunlight was unexpectedly bending around Gaia’s sunshield and entering its protective thermal vent.  The Kourou Project Team couldn’t have found this error at a better time because it would affect Gaia’s ability to measure fainter stars.  As a solution, the team proposed to tilt the shield slightly to eliminate stray light.

So what will this map tell us about our cosmic neighborhood?  When Gaia’s mission is complete, there will be 1 petabyte of data – enough to fit on 200,000 DVDs!  This information will help scientists piece together a picture of the Milky Way’s formation and composition.  The data Gaia gathers allows researchers to learn in-depth details about each star like its brightness, temperature and chemical makeup.  Scientists hope that with Gaia’s help, they will discover new space objects in our territory—exoplanets, comets, icy bodies, and possibly even distant supernovae.  Who knows what astronomers will find years from now, looking back through Gaia’s massive database armed with a generation’s worth of data and knowledge about our galaxy.