NASA's Kepler space telescope to retire
Recently, the Kepler Space telescope has run out of fuel for further Science operations and retired nearly after 9-year mission by NASA. It is the first telescope to find the Earth size habitable planet named Kepler - 60c.
It is an observatory in space dedicated in finding planets outside our solar system which was initially launched in 2009 as a part of the Discorvery Programe by NASA.
The telescope was working well beyond its time limit untill its reaction wheels or gyroscopes failed in may 2018. The telescope targeted the other suspected "habitable" planets and their parent star which are likely to be of Earth size. Since, 2009, the telescope has also discovered extra solar planets in the range of the sizes between the Earth and Neptune.
Since 2009, it has discovered extra-solar planets in the range between the size of Earth and Neptune.
It examined the TRAPPIST-1 system which likely has multiple Earth-sized planets in it between December 2016 and March 2017.