Comets have been studied from a long time and are believed to preserve pristine materials, so they are fundamental to understand the origin of the solar system and life. Starting in the early 1990s, ESA decided to have a more risky and fantastic mission to a comet. As Planetary Cornerstone mission of the ESA Horizon 2000 program, the Rosetta mission was selected with the aim of realizing two asteroid fly-bys, a rendezvous with a comet to deliver a surface science package and to hover around the comet from 4 AU inbound up to perihelion and outbound back to 3.7 AU. The mission was successfully launched on March 2, 2004 with Ariane V that started its 10-year journey toward comet 67P/Churyumov–Gerasimenko. After several planetary gravity assists, Rosetta flew by two asteroids—on September 5, 2008 (Steins) and on July 10, 2010 (Lutetia), respectively, and performed the comet orbit insertion maneuver on August 6, 2014. The onboard instruments characterized the nucleus orbiting the comet at altitudes down to few kilometers. On November 12, 2014, the lander Philae was delivered realizing the first landing ever on a comet surface. Although the exploration of the comet was planned up to the end of 2015, the mission duration was extended for nine more months than the nominal one, to follow the comet on its outbound orbit. To terminate the mission, following a series of very low orbits, a controlled impact of Rosetta spacecraft with the comet was realized on September 30, 2016. The scientific objectives of the mission have been largely achieved. The challenging mission provided the science community with an enormous quantity of data of extraordinary scientific value. In this paper, a detailed description of the mission and the highlights of the obtained scientific results on the exploration of an extraordinary world are presented. The paper also includes lessons learned and directions for the future.

人们对彗星的研究由来已久，人们相信彗星保存着原始物质，因此它们对于了解太阳系和生命的起源至关重要。从 20 世纪 90 年代初开始，欧空局决定对彗星执行一项更具风险、更奇妙的任务。作为欧空局地平线 2000 计划的行星基石任务，罗塞塔任务被选中的目的是实现两次小行星飞越、与彗星交会以提供表面科学包并在彗星周围盘旋，从 4 个天文单位入站到近日点和出站回到 3.7 天文单位。该任务于 2004 年 3 月 2 日成功发射，阿丽亚娜五号开始了为期 10 年的彗星 67P/Churyumov-Gerasimenko 之旅。经过几次行星重力协助后，罗塞塔分别于2008年9月5日（斯坦因）和2010年7月10日（卢泰西亚）飞越了两颗小行星，并于2014年8月6日进行了彗星轨道插入机动。机载仪器表征了彗核以低至几公里的高度绕彗星运行。 2014年11月12日，菲莱号着陆器交付，实现了彗星表面的首次着陆。尽管对这颗彗星的探索计划持续到 2015 年底，但任务持续时间比名义上延长了 9 个月，以便在其出站轨道上跟踪彗星。为了结束这次任务，经过一系列极低轨道飞行，罗塞塔号航天器于2016年9月30日实现了对彗星的受控撞击。任务的科学目标已基本实现。这项具有挑战性的任务为科学界提供了大量具有非凡科学价值的数据。 本文详细介绍了此次任务以及在探索非凡世界方面所取得的科学成果的亮点。该文件还包括经验教训和未来方向。