TESS will do this via the "transit" method, noting the tiny brightness dips that result when a planet crosses the face of its host star from the spacecraft's perspective. This is the same strategy employed by NASA's famed Kepler space telescope, which has found about two-thirds of the 3,700 known exoplanets to date.
But Kepler's finds are mostly faraway worlds at least several hundred light-years from Earth. TESS will aim to find planets close enough to be investigated in depth by other instruments — especially NASA's James Webb Space Telescope, the $8.8 billion behemoth scheduled to launch in 2020. Planned for over a decade by the Massachusetts Institute of Technology (MIT) – originally using seed funding from Google – TESS is expected to find dozens of Earth 2.0 candidates. For the first time, astronomers will get accurate data on the sizes, masses and ages of Earth-like worlds. “We expect TESS will discover a number of planets whose atmospheric compositions hold potential clues to the presence of life, which could be precisely measured by future observers," says George Ricker, TESS principal investigator at MIT's Kavli Institute for Astrophysics and Space Research in Cambridge, which is leading the mission.
By: Swati Kaushal