After its successful launch in December, European Space Agency's (ESA) Gaia has now taken up its position in space and is ready to survey the skies. With the help of two onboard telescopes focused onto the largest ever space camera, Gaia is estimated to catalogue nearly one billion stars in its 5-year mission.
Like Hipparcos before it, ESA's Gaia will map stars in the Milky Way. It will do this by measuring the brightest billion objects and determine their three-dimensional distribution and velocities. It also has the ability to measure the temperature, mass, and chemical composition of these billion objects.
Gaia will be able to discern objects up to 400,000 times dimmer than those visible to the naked eye. The positional accuracy of its measurements are akin to measuring the width of a human hair at a distance of 500 km.
The process will involve scanning each part of the sky an average of 70 times over its five-year mission lifetime, which means scanning the entire sky twice every 63 days, once through each of the two telescopes, making it a powerful tool for spotting time-evolving phenomena such as binary systems, supernovae, and exoplanets. Compared to Hipparcos, Gaia will be able to measure 500 times the number of stars, extending to objects 1000 times dimmer than the dimmest that Hipparcos could catalogue.