NASA's planet-hunting spacecraft begins stellar search

Led by MIT, NASA's Transiting Exoplanet Survey Satellite (TESS) will spend the next two years monitoring the nearest and brightest stars for the tell-tale dips in light that occur when a planet passes in front of them (transits). The mission is expected to find thousands of new planets, some of which could potentially support life.

During its two-year survey, TESS will watch a wide variety of stars, looking for signs of planets ranging from Earth-size to larger than Jupiter. It will do this using four cameras, each equipped with a 16.8-megapixel sensor covering a square 24 degrees wide - large enough to contain an entire constellation.

The cameras are arranged to view a long strip of the sky, called an observation sector. TESS will watch each observation sector for about 27 days before rotating to the next. It will cover the southern sky in its first year, and then begin scanning the north. Over the course of the mission the satellite will study 85 per cent of the sky— an area 350 times greater than what NASA's Kepler mission first observed—making it the first exoplanet mission to survey nearly the entire sky.