NASA’S Kepler probe has confirmed the existence of more than 2600 exoplanets in the course of nine years. Kepler targets Earth lookalikes meaning planes that have the same size and their atmosphere, composition and climate can be studied.
On the forefront of this kind of expeditions is the TESS (Transiting Exoplanet Survey Satellite) a mission of NASA that is scheduled to launch on 16 April. The cost of the mission reaches the $340 million mark and it will try to identify at least 50 exoplanets that look like Earth or even bigger.
TESS like Kepler finds planets by looking at stars and waiting for a dip in brightness as a planet passes in front, blocking the light in a so called transit. The difference between the two is that whereas Kepler had a fixed view of just 0.25% of the sky out to a distance of 3.000 light-years, TESS will observe 85% of the sky, out to about 300 light-years.
The spacecraft will carry four telescopes and will cover a strip of sky extending from the solar’s system pole to its equator, also known as the ecliptic. This will take about 27 days and then it will shift sideways and repeat the process. After having observed 13 such strips over a year, covering almost an entire hemisphere it will flip and observe the other hemisphere. In about two years it will have surveyed close to 2 million stars. The primary target will be red-dwarves as they are the most commonly found in our proximity.
Of course the are other programs underway in Chile the program SPECULOOS will be launched and it will try and find life, meaning habitable planets. Also ESA the European Space Agency will launch another probe for the monitoring of exoplanets, with a main goal of figuring out the densities of various planets.