Introduction: A New Path to Io’s Surface
A recent study presented at the AIAA 2025 Regional Student Conference by Spartan Space Systems at San Jose State University proposes a bold idea for landing on Io, Jupiter’s highly active volcanic moon. The team introduces UNAGI, a lander concept designed to use Jupiter’s magnetic field as a form of propulsion during descent. In doing so, UNAGI aims to reduce onboard propellant needs while still achieving a controlled touchdown on Io’s rugged, volcanically dynamic surface.
UNAGI embodies a deliberate blend of heritage from ongoing Jupiter-system missions and innovative propulsion theory. The concept draws inspiration from NASA’s Juno, and to a broader extent, the Europa Clipper and ESA’s JUICE spacecraft. Among these missions, Juno is actively studying Jupiter, while Europa Clipper and JUICE are on trajectories destined for the Jovian system. The UNAGI researchers argue that combining time-tested mission insight with propellantless techniques could unlock new possibilities for exploring the Galilean moons and other volatile worlds.
UNAGI and the Electrodynamic Tether (EDT) Propulsion
The core of UNAGI is an electrodynamic tether (EDT) propulsion system that interacts with Jupiter’s powerful magnetic field to facilitate descent. The lander uses a 50-kilometer tether to generate Lorentz forces, enabling corrections during the descent without relying on large quantities of traditional propellant. The approach is designed to be complemented by airbags deployed at touchdown, allowing a gentler surface encounter on Io’s uneven terrain. In theory, this propellantless method could free mass for science payloads, extend mission lifetimes, and reduce overall costs, which is a compelling proposition for future deep-space exploration.
As described by the team, EDT works by exploiting the planet-moon environment: the lander’s tether interacts with Jupiter’s magnetic field to produce thrust-like effects or drag, depending on the vehicle’s trajectory and current flow. This enables precise course corrections as the craft nears Io’s surface while minimizing the need for stored chemical or electrical propellants. The payload would then deploy and begin its scientific mission—collecting data on Io’s interior structure, surface changes from volcanic activity, plume activity and outgassing, tectonics, and the moon’s interaction with Jupiter’s magnetosphere. The plan also envisions comparative analyses with Europa, Ganymede, and Callisto to illuminate the broader history of the Jovian system.
Why Io Demands a New Landing Approach
Io’s orbit and its intense volcanism present engineering challenges that differ radically from more quiescent worlds. Tidal forces from Jupiter stretch Io as it orbits in an eccentric path, generating heat and driving hundreds of active volcanoes and lava flows. A landing system must cope with high surface variability, dynamic plumes, and evolving topography. In this context, a propulsion strategy that minimizes propellant while leveraging the surrounding environment becomes particularly attractive. The UNAGI concept argues that an EDT-based descent could make ambitious Io science missions more feasible, potentially enabling longer-term presence and more capable payloads than traditional propellant-dependent landers.
Lessons from Juno, Europa Clipper, and JUICE
The study emphasizes that future Io missions will be informed by the collective experience of Juno, Europa Clipper, and JUICE. Juno’s ongoing observations of Jupiter provide critical context about the planet’s magnetosphere and radiation environment, while Europa Clipper and JUICE offer pathfinding in terms of ice-shell measurements, plume analysis, and dual-mission architectures around Jovian moons. UNAGI leverages these mission learnings by adapting their engineering heritage to a propulsion approach that could reduce mass and simplify descent operations, albeit with new risk considerations tied to high-radiation environments, tether reliability, and the integration of airbags with a magnetically influenced landing sequence.
What Comes Next for UNAGI and Io Exploration?
As a concept presented by students, UNAGI is a starting point for broader dialogue about feasible, cost-efficient approaches to exploring volcanic worlds. The paper invites collaboration across academia and industry to validate EDT physics in relevant space environments, test tether management strategies, and develop robust systems for landing in high-risk terrains. While significant engineering validation remains, the UNAGI idea demonstrates how propellantless propulsion could shape the next generation of Io mission concepts and, more broadly, deep-space exploration strategies.
Conclusion: A Step Toward the Future of Volcanic World Exploration
UNAGI represents more than a single lander concept; it is a catalyst for rethinking how we approach descent, science returns, and mission economics for volatile worlds. The study underlines a central theme in space exploration: the most promising advances often come from blending proven scientific visions with innovative propulsion and systems engineering. As the researchers put it, propellantless propulsion shaped by EDT could be a practical path to enable more science with less fuel, inviting the global community to imagine the possibilities beyond Io and into the broader, dynamic frontier of the solar system.
As always, keep doing science and keep looking up!
