Neptune Odyssey: A Flagship Concept for the Exploration of the Neptune–Triton System

Abstract

The Neptune Odyssey mission concept is a Flagship-class orbiter and atmospheric probe to the Neptune–Triton system. This bold mission of exploration would orbit an ice-giant planet to study the planet, its rings, small satellites, space environment, and the planet-sized moon Triton. Triton is a captured dwarf planet from the Kuiper Belt, twin of Pluto, and likely ocean world. Odyssey addresses Neptune system-level science, with equal priorities placed on Neptune, its rings, moons, space environment, and Triton. Between Uranus and Neptune, the latter is unique in providing simultaneous access to both an ice giant and a Kuiper Belt dwarf planet. The spacecraft—in a class equivalent to the NASA/ESA/ASI Cassini spacecraft—would launch by 2031 on a Space Launch System or equivalent launch vehicle and utilize a Jupiter gravity assist for a 12 yr cruise to Neptune and a 4 yr prime orbital mission; alternatively a launch after 2031 would have a 16 yr direct-to-Neptune cruise phase. Our solution provides annual launch opportunities and allows for an easy upgrade to the shorter (12 yr) cruise. Odyssey would orbit Neptune retrograde (prograde with respect to Triton), using the moon's gravity to shape the orbital tour and allow coverage of Triton, Neptune, and the space environment. The atmospheric entry probe would descend in ∼37 minutes to the 10 bar pressure level in Neptune's atmosphere just before Odyssey's orbit-insertion engine burn. Odyssey's mission would end by conducting a Cassini-like “Grand Finale,” passing inside the rings and ultimately taking a final great plunge into Neptune's atmosphere.

The Geophysical Environment of (486958) Arrokoth—A Small Kuiper Belt Object Explored by New Horizons

“…Similar investigations of the small irregular satellites of the gas giants may also be informative, since these populations are likely captured KBOs. Proposed missions to Uranus and Neptune, including Neptune Odyssey (Rymer et al., 2020), could support these investigations.…”

“…Similar investigations of the small irregular satellites of the gas giants may also be informative, since these populations are likely captured KBOs. Proposed missions to Uranus and Neptune, including Neptune Odyssey (Rymer et al., 2020), could support these investigations. What are the densities of comets? Our expectations for Arrokoth were heavily based on intuition gained from exploration of comets, which were likely formed in the same regions of the Solar System (Moore et al., 2018).…”

The Case for a New Frontiers–Class Uranus Orbiter: System Science at an Underexplored and Unique World with a Mid-scale Mission

“…Another primary design driver for a New Frontiers-class Uranus orbiter mission will be limitations on the total mission duration resulting from the nominal 14 yr flight design life of currently available RPSs (Lee & Bairstow 2015); however, future RPS designs are targeting on longer lifetimes, which have been used as baselines for recent predecadal mission studies designs (e.g., Howett et al 2021;Rymer et al 2021). The preliminary design is a 2 yr baseline mission in orbit at Uranus with a system tour that enables sufficient surface mapping of the large satellites, as well as imaging coverage of the planet, its rings, and the small moons.…”

Operations for Autonomous Spacecraft

“…The notional mission concept was informed by several prior mission concept studies including the Neptune Odyssey mission concept [8], Trident Mission concept [9] and Ice Giants Study [10]. We selected a subset of tour orbits, including several close flybys of Triton, and a subset of representative instruments, specifically, a wide-angle camera, narrow-angle camera, sub-millimeter spectrometer, and plasma and particles instrument.…”