He managed to discover thousands of planets around other stars, which scientists have dubbed "Earth 2.0". TESS's observing pattern, rather than staring at a single part of the sky, will scan almost the entire sky with overlapping fields of view (much like the petals on a flower).Duration of TESS's observations on the celestial sphere, taking into account the overlap between sectors.(Graphic: Nasa) Given what we learned from Kepler, astronomers expect TESS to find thousands more planetary systems.
A recent analysis of Kepler's discoveries suggested that 20 to 50 per cent of the stars visible in the night sky were likely to have small, possibly rocky, planets similar in size to Earth, and located within the habitable zone of their parent stars, which means they're located at distances from their parent stars where liquid water, a vital ingredient to life as we know it, might pool on the planet surface.
But the mission was not without its hiccups - in 2013, mechanical failures stopped Kepler's observations. After completing its primary mission within four years, the spacecraft was repurposed to look at other stars near the zodiacal constellations. By surveying the whole sky, we will find systems that orbit stars 10 times closer and 100 times brighter than those found by Kepler-opening up new possibilities for measuring planet masses and densities, studying their atmospheres, characterizing their host stars, and establishing the full nature of the systems in which the planets reside.
"The Kepler mission was based on a very innovative design". Now, however, Kepler's fantastic journey came to an end, many upcoming missions are waiting in the wings and will take over the exoplanet search. "It was an extremely clever approach to doing this kind of science", said Leslie Livesay, director for astronomy and physics at NASA's Jet Propulsion Laboratory, who served as Kepler project manager during mission development. The mission was re-christened as K2 and continued finding planets for another half decade.
The observation of so many stars has allowed scientists to better understand stellar behaviors and properties, which is critical information in studying the planets that orbit them. In addition to the Kepler data, the archive also offers community-provided data sets for further scientific discoveries. While spacecraft operations have ceased, its data will continue to be publicly available through the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute. Now, however, the spacecraft has run out of its hydrazine fuel and officially entered retirement.
Kepler was replaced by the Transiting Exoplanet Survey Satellite (TESS), which was launched in April.
And those high-profile finales come in the midst of a spree of other spacecraft troubles: the Opportunity rover on Mars remains silent almost five months after a planet-engulfing dust storm, and the Hubble Space Telescope and Chandra X-Ray Observatory were both briefly offline in October.