TESS

The Transiting Exoplanet Survey Satellite (TESS) is a NASA-led space mission designed to discover thousands of exoplanets—worlds orbiting stars outside our solar system. Launched in April 2018, TESS succeeded the Kepler Space Telescope with a specific focus on finding planets around the brightest and nearest stars in our galaxy. Unlike its predecessor, which looked deep into a single small patch of the sky, TESS scans the entire sky in sectors. This wide-angle approach allows it to identify planetary systems that are close enough to Earth for detailed follow-up study by other powerful instruments, such as the James Webb Space Telescope.

TESS operates using the transit method, a technique that monitors the brightness of stars over time. When a planet passes between its host star and the telescope, it temporarily blocks a tiny fraction of the star's light, causing a measurable "dip" in brightness. By observing these repeating patterns, astronomers can calculate a planet's orbital period and its physical size. Beyond finding new worlds, TESS provides invaluable data on stellar activity and the characteristics of host stars. Because it focuses on bright, nearby targets, TESS is building a primary catalog of "neighbor" planets that will help scientists understand the atmospheric composition and potential habitability of worlds beyond our own.