OPEN-ACCESS DATA

By the time it completes its final catalogue

(possibly in 2025), Gaia will have cost the European Space Agency nearly

€740 million (about $1.145 billion) to build, launch and operate, plus another €250 million ($387 million) to convert its raw data into usable form.

But once that processing is completed for each batch of data,

ESA will make it open access – instantly available to every scientist in the world.

“This was not an easy choice,” says Jos de Bruijne, an ESA support scientist for Gaia. But it was a lesson learned from Hipparcos. There, the data was held proprietary for one year and doled out to researchers whose proposals were accepted. Doing this, he says, turned out to be a “non-negligible” task, fraught with all kinds of internal politics. “Not having proprietary data rights simplified things a lot,” he says.