Billion-Star Mapping

Last December the European Space Agency launched the Gaia Spacecraft. Gaia is a space observatory that is suppose to map around billion stars, each star 70 times over the span of 5 years. Using 2 identical telescopes with 1.45m*0.5m primary mirrors looking at say 500nm light, it has a resolution limit of:
θ = 1.22 (500nm/1.45m) = 4.21E-7 rad = .0867''
Since each star will be imaged 70 times Gaia can use parallax to measure the distance to each star. Gaia also will be using Photometric instruments to measure characteristics like temperature and gravity; and Radial Velocity Spectrometers to measure the velocity of stars. After the 5 years of mapping astronomers will have billions of data that will help explain the formation of the universe and perhaps even predict the future.

http://www.space.com/24616-gaia-billion-star-mapping-spacecraft-photo.html