ESA's billion-star surveyor Gaia coming into focus

ESA's billion-star surveyor Gaia is slowly being brought into focus.

Once Gaia starts making routine measurements, it will generate truly enormous amounts of data. To maximise the key science of the mission, only small 'cut-outs' centred on each of the stars it detects will be sent back to Earth for analysis.

The test picture, taken as part of commissioning the mission to 'fine tune' the behaviour of the instruments, is one of the first proper 'images' to be seen from Gaia, but ironically, it will also be one of the last, as Gaia's main scientific operational mode does not involve sending full images back to Earth.

Gaia was launched on 19 December 2013, and is orbiting around a virtual point in space called L2, 1.5 million kilometres from Earth.

Gaia's goal is to create the most accurate map yet of the Milky Way.

It will make precise measurements of the positions and motions of about 1 percent of the total population of roughly 100 billion stars in our home Galaxy to help answer questions about its origin and evolution.

Repeatedly scanning the sky, Gaia will observe each of its billion stars an average of 70 times each over five years. In addition to positions and motions, Gaia will also measure key physical properties of each star, including its brightness, temperature and chemical composition.