Humanity will soon have an extra eye in the search for a distant cousin of our Earth. Waiting for the Webb space telescope, which is scheduled to launch in 2020, will be TESS (Transiting Exoplanet Survey Satellite) to search for stars in search of extrasolar planet.
The launch of TESS
The telescope will be launched from a SpaceX Falcon 9 rocket on April 18, 2018 and the first stage will perform a controlled landing and will be re-used. It will be a first time, in fact it will be the first scientific mission of NASA whose launch is entrusted to the company of Musk. The launch was delayed due to a technical problem with the navigation system, essential for the correct positioning of the telescope in orbit.
What is TESS and how it will help us discover new exoplanets
Thanks to a particular system of large-field lenses, TESS will be able to observe about 85% of the sky in the two planned years, looking for extrasolar planets with the transit method around stars within 200 parsecs from the Earth, about 600 light years. Of all the stars in this range, TESS will focus its attention on the stars of class G and K with an apparent magnitude of 5 to 12. According to the simulations, the new telescope should allow us to discover thousands of new exoplanets.
The orbit will be very special. In fact, if Kepler, the predecessor of TESS, had observed a single portion of the sky equal to 0.28% of the total surface, the new space telescope was designed to observe almost the entire celestial sphere. In particular, the celestial vault has been divided into 26 sectors each large 24° x 96°. Each sector will be observed for two orbits, each of which is about 13.7 days long. The exploration of TESS will last two years, the first one dedicated to the southern hemisphere and the second one dedicated to the northern hemisphere. This particular orbit system has also been studied to aim the telescope always in the opposite direction to the Sun, away from solar radiation.
From a technical point of view, the telescope will consist of four CCD cameras, each of which will be able to set a field equal to 24° x 24° and will be equipped with a seven-element optical scheme and a band-pass filter between 600 and 1000 nm.
The data collected by TESS will be very many and very important: think that every day about 27 GB of information will be sent to the Earth! The space telescope will allow you to build a list of candidates, which will then be skimmed using telescopes on Earth and other tools that will be implemented and put into operation in the near future. Knowing the parameters of the planets, scientists can also determine their composition, thus determining whether they are rocky or gaseous planets.
The TESS space telescope, highlighting the four CCD cameras and solar panels.