TESS, which is also known as, the “Exoplanet Hunter” is a refrigerator-sized satellite that lifted off from the Cape Canaveral Air Force Station on 18th April 2018. The first few days will witness the deployment of solar arrays and a variety of system checks before actually beginning its work. The instrument on TESS has 4 CCD cameras which will be turned on only after 8 days after the launch.
TESS has been instructed to move to an orbit that has never been occupied by any other spacecraft. It is a very wide elliptical path in which the planet will be circled twice by the satellite for every orbit completed by the moon. The orbit is a very stable one and there is no chance of the spacecraft to be affected by any space radiation or orbital debris which will allow trouble-free communication with the team members on Earth. Another advantage is that the satellite will not have to perform a lot of altitude corrections in the orbit and if by chance the spacecraft moves off course too much, it will be pulled back in line by the moon’s gravity. The spacecraft is expected to reach its operating orbit only by mid-June.
TESS can be said as a more advanced version of the Kepler telescope and is expected to beat the Kepler in terms of the number of exoplanets detected. The small-sized telescope packs a huge science push in it. The mission duration of TESS is for 2 years and in this time it will monitor the light of more than 200,000 stars to observe the occurrence of transits (minute dips in starlight). A tiny portion of the starlight will be blocked by its host star when it orbits in front of it. These dips will be observed and recorded by the ultrasensitive cameras of TESS. The same strategy has been used by the Kepler and has successfully confirmed more than 2,600 alien worlds.
The mission will make use of the combined data from TESS as well as other telescopes on both Earth and space to confirm which of the detected ones the real planets are. But some of these planets must be close to Earth to be detected by other telescopes. TESS is expected to cover about 85 percent of the sky over its mission duration and to discover thousands of planets as well as galaxies.