Conceptual design of an ice giant orbital exploration mission

Uranus and Neptune are key targets for investigating the origins of the solar system and planets. Moreover, due to the subsurface ocean on Triton, the Neptune system is also regarded as a breakthrough avenue for the search for extraterrestrial life and the origins of life, offering rich scientific value. Currently, only the Voyager program has conducted short-duration flyby observations of the ice giants, yielding limited scientific results. Implementing higher-level missions, such as orbital exploration of the ice giants and long-term observations, to study the morphology of target celestial bodies, planetary rings, atmospheric structure and composition, atmospheric dynamics, magnetospheres, ionospheres, and subsurface oceans can fill many gaps across space physics, space astronomy, and planetary science. With China’s enhanced deep-space exploration capabilities and major progress in space nuclear power technology, the technical foundation is now in place to carry out orbital exploration of the ice giants. However, ice giant missions face enormous challenges, including long travel distances, extended mission durations, multiple targets, and unknown environments. There is an urgent need to develop spacecraft technologies capable of reaching 30 astronomical units and conducting long-term observations, driving advances in areas such as trajectory design, power systems, TT&C and data transmission, autonomous navigation, and spacecraft autonomous management. The characteristics of ice giant exploration targets and the international progress in ice giant missions are analyzed in this paper. Considering Neptune and Triton’s unique value for studies of extraterrestrial habitability, Neptune is identified as the preferred target for the ice giant orbital exploration mission. This paper defines three main scientific objectives for ice giant orbital exploration: studies of atmospheric and geological activity in ice giant systems; investigations of the space environment of ice giant systems; and exploration of Triton’s subsurface ocean. Centered on these scientific goals, this paper specifies that the mission will carry 11 scientific instruments across four categories: fields and waves measurements, particle detection, optical remote sensing, and gas composition analysis. In terms of mission design, it proposes a concept to achieve Neptune orbital exploration, atmospheric entry, and close flybys of Triton within a single mission, and presents a preliminary spacecraft design. The probe will use two RTGs with 300 We electrical output each (initial total power consumption of 600 We), enabling it to reach 30 astronomical units and operate the long-term scientific exploration. Launch is planned around 2033, with arrival at Neptune after 15 years to conduct scientific observations, and with opportunities for Triton flybys and remote sensing. Based on the mission profile and technical challenges, this paper provides a detailed analysis of technology pathway choices in space nuclear power, ultra-long-distance communications, high-precision autonomous navigation, autonomous mission planning, and atmospheric entry, and offers implementation recommendations for China’s ice giant orbital exploration, providing valuable reference for subsequent mission formulation.