Io is the most volcanically-active object in the solar system. The moon ejects a tonne per second of sulphur-rich gases that fill the vast magnetosphere of Jupiter and drives million-amp electrical currents that excite strong auroral emissions. We present the case for including a detailed study of Io within Voyage 2050 either as a standalone mission or as a contribution to a NASA New Frontiers mission, possibly within a Solar System theme centred around current evolutionary or dynamical processes. A comprehensive investigation will provide answers to many outstanding questions and will simultaneously provide information on processes that have formed the landscapes of several other objects in the past. A mission investigating Io will also study processes that have shaped the Earth, Moon, terrestrial planets, outer planet moons, and potentially extrasolar planets. The aim would be simple – tracing the mass and energy flows in the Io-Jupiter system.

木卫一是太阳系中火山活动最活跃的天体。月球每秒喷出一吨富含硫的气体，这些气体充满木星广阔的磁层，并驱动百万安培的电流，激发强烈的极光辐射。我们提出了在 Voyage 2050 中包括对 Io 的详细研究的案例，无论是作为独立任务还是作为对 NASA New Frontiers 任务的贡献，可能在以当前进化或动力学过程为中心的太阳系主题内。一项全面的调查将为许多悬而未决的问题提供答案，同时提供有关过去形成其他几个物体景观的过程的信息。调查木卫一的任务还将研究塑造地球、月球、类地行星、外行星卫星的过程，和潜在的太阳系外行星。目标很简单——追踪 Io-Jupiter 系统中的质量和能量流。