An image taken by NASA’s Transiting Exoplanet Survey Satellite (TESS) shows a swath of the southern sky along the plane of our Milky Way Galaxy.
Illustration of NASA’s TESS spacecraft observing an M-dwarf star with orbiting planets. Image credit: NASA’s Goddard Space Flight Center.
TESS 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.
This new planet-hunter will focus on stars between 30 and 300 light-years away. It will survey more than 200,000 target stars, viewing large parts of the sky for 27 days at a time.
For its two-year mission, astronomers divided the sky into 26 sectors: TESS will use four unique wide-field cameras to map 13 sectors encompassing the southern sky during its first year of observations and 13 sectors of the northern sky during the second year, altogether covering 85% of the sky.
The telescope 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.
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.
This test image from one of the four cameras aboard NASA’s TESS spacecraft captures a swath of the southern sky along the plane of the Milky Way. Image credit: NASA / MIT / TESS.
On May 17, TESS passed about 5,000 miles (8,050 km) from the Moon, which provided a gravity assist that helped the spacecraft sail toward its final working orbit.
TESS will undergo one final thruster burn on May 30 to enter its science orbit around Earth.
This highly elliptical orbit will maximize the amount of sky the telescope can image, allowing it to continuously monitor large swaths of the sky.
TESS is expected to begin science operations in mid-June after reaching this orbit and completing camera calibrations.
As part of camera commissioning, the TESS team snapped a two-second test exposure using one of its four cameras.
The image, centered on the southern constellation Centaurus, reveals more than 200,000 stars. The edge of the Coalsack Nebula is in the right upper corner and the bright star Beta Centauri is visible at the lower left edge.
TESS is expected to cover more than 400 times as much sky as shown in this image with its four cameras during its initial two-year search for exoplanets.
