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NASA's next exoplanet hunting mission

Artist's rendition of TESS in space (Credit: NASA's Goddard Space Flight Center)

Almost 4,000 planets have been discovered outside of our solar system — some of which might be habitable. A series of upcoming missions could add tens of thousands more planets to that list, starting “a whole new era of exoplanet opportunities,” according to MIT astronomer Sara Seagar, who spoke on the topic at the winter meeting of the American Astronomical Society.

The mission: The Transiting Exoplanet Survey Satellite, or TESS, is set to launch into orbit around Earth in March. Its wide-angle cameras will, over the course of two years, photograph almost 85% of the sky in order to detect the brief dips of light caused by a planet passing in front of a star. The database it creates will guide missions for decades to come.

NASA's Kepler missions found most of the planets discovered so far. Kepler was designed to figure out how many planets were in one small part of the sky so researchers could estimate how many there may be in total. It looked at 0.25% of the sky, but peered as far at 3000 light years away.

What's new: TESS will look at almost all of the sky, but it will focus on stars that neighbor our solar system and could be studied with future telescopes.

Coincidentally, most of the stars close to us are small, cold so-called M dwarf stars. It’s easier to look for habitable planets around M dwarfs because any planets capable of supporting life will need to be closer to the stars. That means that when the planet passes in front of the star, it’ll block out a larger, more detectable region of light. Additionally, those planets will take less time to orbit their stars, meaning we’ll have more opportunities to catch them passing by.

What’s next: More than 140 non-NASA proposals to use TESS's capabilities were also submitted, and roughly 1 in 4 will be selected in a few months. They’ll look at planets in the solar system, planets outside of it, and even galaxies.

Additionally, researchers will select 50 targets out of the massive catalogue of stars and planets TESS will create. These planets will likely be close in size to Earth, and considered the best candidates for possibly supporting life. The James Webb Space Telescope, which is scheduled to launch about a year after TESS starts gathering data, will take a closer look at those planets to learn more about their composition and atmosphere.

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