What is Transiting Exoplanet Survey Satellite (TESS)?

About Transiting Exoplanet Survey Satellite (TESS):

• It is a NASA mission that's searching for planets orbiting the brightest stars in Earth's sky. 
• The satellite is a follow-up to NASA's highly successful Kepler space telescope, which found thousands of exoplanets during a decade of work after its launch in 2009.
• Launch: It was launched on April 18, 2018, aboard a SpaceX Falcon 9 rocket out of Cape Canaveral.
• Orbit: TESS circles Earth in a unique high Earth orbit of 12 to 15 days, which is inclined in such a way that the telescope’s sky view islargely free from obstructionsby our bright planet and the Moon.
• Over the course of its two-year primary mission, TESS’ four sensitive cameras systematicallyscanned over 200,000 of the nearest and brightest stars, imaging 75% of the sky. It found 2,100 planetary candidates and 66 confirmed exoplanets.
• The prime mission ended on July 4, 2020, and TESS is now on an extended mission.
• TESS is finding planets ranging from small, rocky worlds to giant planets, showcasing the diversity of planets in the galaxy. 

How does TESS find exoplanets?

• It uses the transit method to detect planets.
• It looks for periodic dips in stars' brightness as planets cross in front of them along our sightline.
• The larger the planet, the greater the drop in brightness during the transit. 
• How long it takes a planet to pass in front of the star and come back tells us the shape of its orbit.
• This method reveals the diameter of the planet and the size of its orbit.
• Orbits within a certain range lie in the “habitable zone”, where liquid water can exist on the surface of an Earth-like world. 

Q1: What is the Kepler space telescope?

It was NASA’s first planet-hunting mission, assigned to search a portion of the Milky Way galaxy for Earth-sized planets orbiting stars outside our solar system. It was launched on March 6, 2009.In December 2011, NASA announced that Kepler had found its first planet, Kepler-22b, in the habitable zone of a star. On October 30, 2018, after nine years in deep space collecting data, NASA announced that Kepler had run out of fuel. The spacecraft was retired in its current, safe orbit, away from Earth.

Source:Astronomers Find Super-Earth Exoplanet in Habitable Zone of TOI-715