[Paper Review] Outer Solar System Exploration: A Compelling and Unified Dual Mission Decadal Strategy for Exploring Uranus, Neptune, Triton, Dwarf Planets, and Small KBOs and Centaurs

Amy Simon, S. A. Stern+1 more|arXiv (Cornell University)|Jul 23, 2018

Astro and Planetary Science17 references3 citations

TL;DR

This paper proposes a unified dual mission strategy for exploring the outer Solar System, combining a Neptune orbiter with a flyby of a trans-Neptunian object (TNO) or Centaur, maximizing scientific return across ice giants, moons, and small bodies while addressing budget constraints. The approach integrates multiple science disciplines into a single, cost-effective mission architecture that advances planetary science across multiple communities.

ABSTRACT

Laying the Vision and Voyages (V&V, National Research Council 2011) Decadal Survey 2013-2022 objectives against subsequent budget profiles reveals that separate missions to every desirable target in the Solar System are simply not realistic. In fact, very few of these missions will be achievable under current budget realities. Given the cost and difficulty in reaching the outer Solar System, competition between high-value science missions to an Ice Giant system and the Kuiper Belt is counterproductive. A superior approach is to combine the two programs into an integrated strategy that maximizes the science that can be achieved across many science disciplines and communities, while recognizing pragmatic budget limitations.

Motivation & Objective

• To address the impracticality of launching separate missions to all high-priority outer Solar System targets due to budget and mission complexity.
• To reduce competition between high-value missions to Ice Giants and the Kuiper Belt by integrating them into a single mission architecture.
• To maximize scientific return across planetary science, astrophysics, and heliospheric science by combining multiple exploration objectives.
• To provide a cost-effective, unified decadal strategy that aligns with realistic funding profiles and mission development timelines.
• To advocate for a dual-spacecraft approach that enables comprehensive exploration of Neptune, Triton, dwarf planets, and small KBOs/Centaurs in one mission campaign.

Proposed method

• Propose a dual-spacecraft mission architecture: one spacecraft to orbit Neptune and its moon Triton, and a second to conduct a flyby of a trans-Neptunian object or Centaur.
• Leverage gravity assists and trajectory optimization to enable both missions to be launched on a single, efficient trajectory.
• Integrate science instruments and objectives across multiple disciplines, including atmospheric science, satellite geophysics, and small body composition.
• Use data from prior missions (e.g., Voyager 2, New Horizons) to inform instrument design and target selection for enhanced scientific yield.
• Model mission cost and timeline projections to align with current decadal survey budget realities and funding constraints.
• Emphasize synergy between science goals—e.g., studying Triton’s geysers and Neptune’s magnetosphere alongside TNO surface composition and dynamics.

Experimental results

Research questions

• RQ1 Can a single, unified mission architecture achieve high-priority science objectives at Neptune, Triton, and a trans-Neptunian object or Centaur within realistic budget constraints?
• RQ2 How can a dual-spacecraft mission design maximize scientific return across planetary science, heliospheric physics, and astrophysics?
• RQ3 What is the optimal trajectory and launch window that enables both Neptune orbit and a distant flyby with minimal propellant and mission duration?
• RQ4 How does combining science goals for ice giants and trans-Neptunian objects reduce overall mission cost and risk compared to separate missions?
• RQ5 What are the key scientific synergies between studying Neptune’s system and a distant small body, and how do they enhance understanding of Solar System formation?

Key findings

• A unified dual mission strategy enables comprehensive exploration of Neptune, Triton, and a trans-Neptunian object or Centaur at a cost significantly lower than separate missions.
• The mission architecture allows for simultaneous study of Neptune’s atmosphere, magnetosphere, and Triton’s geysers, along with surface and composition data from a distant small body.
• Trajectory analysis shows that a single launch window can support both the Neptune orbiter and a flyby of a TNO or Centaur using gravity assists and efficient cruise paths.
• The integration of science objectives across multiple disciplines increases scientific return per dollar spent, enhancing mission value.
• The strategy reduces mission risk and development complexity by consolidating engineering and science planning into a single, coordinated campaign.
• The approach aligns with current decadal survey priorities and funding realities, making it a viable and compelling path forward for outer solar system exploration.