"The
European Space Agency's Gaia spacecraft is poised to begin its mission to map a billion stars in our galaxy to an unprecedented level of detail, with its scheduled launch on Thursday...
The starry "census" will record many parameters including stars' distances from the Earth accurate to around 1%...
Gaia will record data for around 1% of the 100 billion stars in our galaxy..
...the Hipparcos catalogue (only) containing 118,218 stars."
http://www.theguardian.com/science/2...n-3d-map-stars