Abstract Uranus and Neptune, and their diverse satellite and ring systems, represent the least explored environments of our Solar System, and yet may provide the archetype for the most common outcome of planetary formation throughout our galaxy. Ice Giants will be the last remaining class of Solar System planet to have a dedicated orbital explorer, and international efforts are under way to realise such an ambitious mission in the coming decades. In 2019, the European Space Agency released a call for scientific themes for its strategic science planning process for the 2030s and 2040s, known as Voyage 2050. We used this opportunity to review our present-day knowledge of the Uranus and Neptune systems, producing a revised and updated set of scientific questions and motivations for their exploration. This review article describes how such a mission could explore their origins, ice-rich interiors, dynamic atmospheres, unique magnetospheres, and myriad icy satellites, to address questions at the heart of modern planetary science. These two worlds are superb examples of how planets with shared origins can exhibit remarkably different evolutionary paths: Neptune as the archetype for Ice Giants, whereas Uranus may be atypical. Exploring Uranus’ natural satellites and Neptune’s captured moon Triton could reveal how Ocean Worlds form and remain active, redefining the extent of the habitable zone in our Solar System. For these reasons and more, we advocate that an Ice Giant System explorer should become a strategic cornerstone mission within ESA’s Voyage 2050 programme, in partnership with international collaborators, and targeting launch opportunities in the early 2030s.

中文翻译：

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冰巨人系统：天王星和海王星轨道任务的科学潜力

摘要 天王星和海王星，以及它们多样化的卫星和环系统，代表了我们太阳系中探索最少的环境，但可能为整个银河系中行星形成的最常见结果提供原型。冰巨人将是太阳系中最后一颗拥有专用轨道探测器的行星，国际社会正在努力在未来几十年内实现这一雄心勃勃的任务。2019 年，欧洲航天局发布了其 2030 年代和 2040 年代战略科学规划过程（称为航程 2050）的科学主题呼吁。我们利用这个机会回顾了我们目前对天王星和海王星系统的了解，产生了一个修订和更新了一套科学问题和探索动机。这篇评论文章描述了这样的任务如何探索它们的起源、富含冰的内部、动态大气、独特的磁层和无数冰冷的卫星，以解决现代行星科学的核心问题。这两个世界是具有共同起源的行星如何表现出截然不同的进化路径的极好例子：海王星是冰巨人的原型，而天王星可能是非典型的。探索天王星的天然卫星和海王星捕获的卫星海卫一可以揭示海洋世界如何形成和保持活跃，重新定义我们太阳系中宜居带的范围。出于这些以及更多原因，我们主张与国际合作者合作，冰巨人系统探索者应该成为欧空局 2050 年航程计划中的战略基石任务，