Planet-hunting satellite launches from Cape Canaveral

Two-year mission will survey bright stars between 30 and 300 light years from Earth.
By Laurel Kornfeld | Jan 18, 2019
NASA's Transiting Exoplanet Survey Satellite (TESS), the successor to the Kepler mission, successfully launched from Cape Canaveral Air Force Station in Florida at 6:51 PM EDT on Wednesday, April 18.

The two solar arrays that will power the probe successfully deployed an hour later, at 7:53 PM.

TESS will use six thruster burns over the next several weeks, each of which will put it in a more elongated orbit, until the spacecraft approaches the Moon. A gravitational assist from the Moon will transfer it into its science orbit, which will take it around the Earth every 13.7 days.

Before TESS's actual science work begins, its instruments will undergo testing for about 60 days.

During its two-year mission, TESS will use four specially-built wide-field cameras to map the sky, which has been divided into 26 sectors, 13 in the southern sky and 13 in the northern sky.

The probe will use the transit method, which involves measuring periodic reductions in a star's light as an orbiting planet passes in front of that star, and will cover 85 percent of the sky.

Of the 3,700 confirmed exoplanets discovered since 1992, 78 percent have been found via the transit method. Kepler, which observed faint stars ranging from 300 to 3,000 light years away, discovered more than 2,600 of these planets.

TESS will look closer to home by studying stars 30 to 100 times brighter than those observed by Kepler, at a distance ranging from 30 to 300 light years away.

"We are thrilled TESS is on its way to help us discover worlds we have yet to imagine, worlds that could possibly be habitable or harbor life," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate. "With missions like the James Webb Space Telescope (JWST) to help us study the details of these planets, we are ever the closer to discovering whether we are alone in the universe."

Concentrating on bright stars will enable TESS to use spectroscopy to measure the absorption and emission of light and use this data to determine a planet's mass, density, and atmospheric conditions. Identifying atmospheric molecules will help scientists determine the habitability of individual planets.

"The targets TESS finds are going to be fantastic subjects for research for decades to come," noted mission project scientist Stephen Rinehart of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Mission principal investigator George Ricker of the Massachusetts Institute of Technology (MIT) Kavli Institute for Astrophysics and Space Research, stated, "One critical piece for the science return of TESS is the high data rate associated with its orbit. Each time the spacecraft passes close to Earth, it will transmit full-frame images taken with the cameras. That's one of the unique things TESS brings that was not possible before."


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