NASA's TESS Space Telescope Begins Hunt for Undiscovered Planets

NASA's new planet-hunting space telescope TESS (Transiting Exoplanet Survey Satellite) has begun its hunt for undiscovered worlds, the government agency has announced.

The spacecraft will scour the skies monitoring more than 200,000 nearby stars for new exoplanets—planets that lie beyond our solar system. Some of these may reside in the habitable zone of their host star, in which case they would become targets for future missions that could assess their ability to harbor life.

The spacecraft is expected to beam back its first collection of scientific data in August, and every 13.5 days after that, when it periodically reaches the point in its orbit that is closest to Earth. Once the first dataset has been received, TESS scientists will begin combing through the information to identify any signs of new planets.

"TESS will search 85 percent of our sky for exoplanets orbiting bright stars and our nearest stellar neighbors," Martin Still, NASA headquarters program scientist for TESS, told Newsweek. "It will allow us to follow up planet detections using other telescopes, such as the James Webb Space Telescope, to then better explore the properties of these planets."

TESS, which was launched aboard a SpaceX Falcon 9 rocket, is equipped with four wide-field cameras that will enable it to search for exoplanets over its two-year mission with the help of a phenomenon known as transit. This is when a planet passes in front of its star (from an observer's point of view) causing a periodic and regular dip in brightness.

Astronomers often use this method to identify the presence of planets. NASA's Kepler spacecraft, for example, has identified more than 2,600 confirmed exoplanets this way.

An artist’s illustration of the Transiting Exoplanet Survey Satellite. NASA's Goddard Space Flight Center

The focus of TESS's search will be on bright stars less than 300 light years away. Using the light they generate, researchers will be able to use spectroscopy—a technique that measures the absorption and emission of light—to determine a planet's mass, density and atmospheric composition, which could provide insights into whether or not it harbors life.

"I'm thrilled that our new planet hunter mission is ready to start scouring our solar system's neighborhood for new worlds," Paul Hertz, astrophysics division director at NASA Headquarters, Washington, said in a statement. "Now that we know there are more planets than stars in our universe, I look forward to the strange, fantastic worlds we're bound to discover."

But it's not just new worlds that TESS will find, according to Padi Boyd, a project scientist for the mission.

"Scientists will use TESS to study some of the coolest phenomena in astronomy, like how stars and galaxies behave and evolve with time," she told Newsweek. "There's something for everyone to learn about from the TESS mission."

This article has been updated to include additional comments from Padi Boyd.