<Li> 2014: Ceres was found to have an atmosphere with water vapor, confirmed by the Herschel space telescope . </Li> <Li> 2015: The NASA Dawn spacecraft approached and orbited Ceres, sending detailed images and scientific data back to Earth . </Li> <P> In 1981, a proposal for an asteroid mission was submitted to the European Space Agency (ESA). Named the Asteroidal Gravity Optical and Radar Analysis (AGORA), this spacecraft was to launch some time in 1990--1994 and perform two flybys of large asteroids . The preferred target for this mission was Vesta . AGORA would reach the asteroid belt either by a gravitational slingshot trajectory past Mars or by means of a small ion engine . However, the proposal was refused by ESA . A joint NASA--ESA asteroid mission was then drawn up for a Multiple Asteroid Orbiter with Solar Electric Propulsion (MAOSEP), with one of the mission profiles including an orbit of Vesta . NASA indicated they were not interested in an asteroid mission . Instead, ESA set up a technological study of a spacecraft with an ion drive . Other missions to the asteroid belt were proposed in the 1980s by France, Germany, Italy, and the United States, but none were approved . Exploration of Ceres by fly - by and impacting penetrator was the second main target of the second plan of the multiaimed Soviet Vesta mission, developed in cooperation with European countries for realisation in 1991--1994 but canceled due to the Soviet Union disbanding . </P> <P> In the early 1990s, NASA initiated the Discovery Program, which was intended to be a series of low - cost scientific missions . In 1996, the program's study team recommended as a high priority a mission to explore the asteroid belt using a spacecraft with an ion engine . Funding for this program remained problematic for several years, but by 2004 the Dawn vehicle had passed its critical design review . </P>

Where can dwarf planets be found in the solar system