The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor more than 200,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat.
The Transiting Exoplanet Survey Satellite (TESS) is a planned space telescope for NASA's Explorers program, designed to search for exoplanets using the transit method.
The primary mission objective for TESS is to survey the brightest stars near the Earth for transiting exoplanets over a two-year period. The TESS project will use an array of wide-field cameras to perform an all-sky survey. It will scan nearby stars for exoplanets
TESS will provide prime targets for further characterization by the James Webb Space Telescope, as well as other large ground-based and space-based telescopes of the future.
In order to obtain unobstructed imagery of both the northern and southern hemispheres of the sky, TESS will utilize a 2:1 lunar resonant orbit called P/2, a never-before-used orbit. The spacecraft's 373,000 km (232,000 mi) apogee is timed to keep the craft away from the Moon, which acts as a destabilizing agent. This highly elliptical orbit should remain stable for decades, and will keep TESS's cameras in a stable temperature range. The majority of the orbit is spent outside the Van Allen belts to avoid radiation damage to TESS. Every 13.7 days at its perigee of 108,000 km (67,000 mi), TESS will downlink the data it has collected during the orbit to Earth over a period of approximately three hours.
TESS's survey will focus on nearby G- and K-type stars with apparent magnitudes brighter than magnitude 12.Approximately 500,000 stars will be studied, including the 1,000 closest red dwarfs, across an area of sky 400 times larger than covered by the original Kepler mission. TESS is expected to discover more than 3,000 transiting exoplanet candidates, including those which are Earth sized or larger. Of those discoveries, an estimated twenty could be super-Earths located in the habitable zone around a star.
Exoplanet candidates could later be investigated by the Automated Planet Finder telescope, the HARPS spectrometer and both the future ESPRESSO spectrometer and James Webb Space Telescope.
The James Webb Space Telescope, set for launch in 2018, will be the first able to actually measure the atmospheric composition of a rocky, possibly Earthlike planet far off in space, and so vastly enhance the search for life.
The James Webb Space Telescope (JWST), previously known as Next Generation Space Telescope (NGST), is a space observatory under construction and scheduled to launch in October 2018. The JWST will offer unprecedented resolution and sensitivity from long-wavelength visible to the mid-infrared, and is a successor instrument to the Hubble Space Telescope and the Spitzer Space Telescope. The telescope features a segmented 6.5-meter (21 ft) diameter primary mirror and will be located near the Earth–Sun L2 point. A large sunshield will keep its mirror and four science instruments below 50 K