Gaia is an ambitious project from the European Space Agency to create the most precise map of a billion stars in our Galaxy and millions of other celestial objects invisible from current telescopes. When the spacecraft is launched in 2010, it will carry the most sensitive cameras ever made. Its billion-pixel camera will be in fact composed of 170 separate cameras, tiled together in a mosaic to register every object that passes through the field of view. Each individual camera or 'charge-coupled device' (CCD) will have a resolution of almost nine million pixels. Gaia will take images for five years. The above link will provide you with more details about this billion-pixel camera, but here I chose to focus on a particular aspect of the mission: checking the usually unobversable asteroids between the Sun and the Earth because of light conditions. Read more...