NASA’s Transiting Exoplanet Survey Satellite (TESS) has begun its search for planets around stars within 300 light-years of the Sun.
An artist’s illustration of NASA’s Transiting Exoplanet Survey Satellite. Image credit: NASA’s Goddard Space Flight Center.
TESS is the first space-based, all-sky surveyor to search for alien worlds.
The spacecraft was launched on April 18, 2018, with a SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
It will study 85% of the sky and will watch a wide variety of stars, looking for signs of planets ranging from Earth-size to larger than Jupiter.
The planet hunter has four cameras arranged to view a long strip of the sky called an observation sector. Each of its cameras has a 16.8-megapixel sensor covering a square 24 degrees wide — large enough to contain an entire constellation.
It will watch each observation sector for about 27 days before rotating to the next. It will cover the southern sky in its first year, and then begin scanning the north.
TESS will be watching for phenomena called transits. A transit occurs when a planet passes in front of its star from the observer’s perspective, causing a periodic and regular dip in the star’s brightness. More than 78% of the approximately 3,700 confirmed exoplanets have been found using transits.
NASA’s Kepler Space Telescope found more than 2,600 exoplanets, most orbiting faint stars between 300 and 3,000 light-years from Earth, using this same method of watching for transits.
TESS will focus on stars between 30 and 300 light-years away and 30 to 100 times brighter than Kepler’s targets.
The brightness of these target stars will allow astronomers to use spectroscopy, the study of the absorption and emission of light, to determine a planet’s mass, density and atmospheric composition. Water, and other key molecules, in its atmosphere can give us hints about a planets’ capacity to harbor life.
TESS is expected to transmit its first series of science data back to Earth in August, and thereafter periodically every 13.5 days, once per orbit, as the spacecraft makes it closest approach to our planet.
“I’m thrilled that our new planet hunter mission is ready to start scouring our Solar System’s neighborhood for new worlds,” said Dr. Paul Hertz, director of the Astrophysics Division in the Science Mission Directorate at NASA Headquarters, Washington.
“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.”
