In November 2013, astronomers estimated, based on Kepler space mission data, that there could be as many as 40 billion rocky Earth-size exoplanets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. Four planets have been confirmed through Kepler's K2 mission. īy January 2015, Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 star systems, along with a further 3,199 unconfirmed planet candidates. On May 16, 2014, NASA announced the approval of the K2 extension. This would include utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs.
On November 18, 2013, the K2 "Second Light" proposal was reported. NASA had asked the space science community to propose alternative mission plans "potentially including an exoplanet search, using the remaining two good reaction wheels and thrusters". This meant the current mission needed to be modified, but it did not necessarily mean the end of planet hunting. On August 15, 2013, NASA announced that they had given up trying to fix the two failed reaction wheels. Then, on May 11, 2013, a second reaction wheel failed, disabling the collection of science data and threatening the continuation of the mission. Initially, in 2012, the mission was expected to be extended until 2016, but on July 14, 2012, one of the spacecraft's four reaction wheels used for pointing the spacecraft stopped turning, and completing the mission would only be possible if all other reaction wheels remained reliable. The initial planned lifetime was 3.5 years, but greater-than-expected noise in the data, from both the stars and the spacecraft, meant additional time was needed to fulfill all mission goals. The Ames Research Center was responsible for the ground system development, mission operations since December 2009, and scientific data analysis. At this time, the high-gain antenna was changed from a gimbal-led design to one fixed to the frame of the spacecraft to reduce cost and complexity, at the cost of one observation day per month. It was delayed again by four months in March 2006 due to fiscal problems. In January 2006, the project's launch was delayed eight months because of budget cuts and consolidation at NASA. The telescope's construction and initial operation were managed by NASA's Jet Propulsion Laboratory, with Ball Aerospace responsible for developing the Kepler flight system. The Kepler space telescope was part of NASA's Discovery Program of relatively low-cost science missions. Kepler observed 530,506 stars and detected 2,662 planets.
Only planets whose orbits are seen edge-on from Earth could be detected. These data were transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. ĭesigned to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approximately 150,000 main sequence stars in a fixed field of view. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018. The principal investigator was William J. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. The Kepler space telescope is a retired space telescope launched by NASA in 2009 to discover Earth-size planets orbiting other stars. Artist's impression of the Kepler telescope