Credit: Saturn Ring Skimmer Mission Concept team

A possible next step to explore Saturn’s rings, atmosphere, interior, and inner magnetosphere is the Saturn Ring Skimmer mission concept.

The mission would be a ballistic tour that passes repeatedly at low altitude over Saturn’s main rings. In the span of only 162 days, and without using any propellant, one possible tour covers the main ring regions in 13 low-altitude passes. But nothing prevents a much longer ring-skimming tour from being designed.

Artistic view of Cassini exploring Saturn.
Credit: NASA/JPL-Caltech

A spacecraft following this trajectory would get roughly 100 times closer to the rings than NASA’s Cassini mission when its best ring images were taken. Cassini was launched in 1997, ending its 13-year tour of the ringed planet in mid-September 2017.

Proximity to the rings

The promise of the Skimmer would be obtaining images with far better spatial resolution. In addition, the spacecraft’s proximity to the rings allows for on-the-spot measurements of the material surrounding the rings, including the ring’s tenuous atmosphere, dust released by collisions into the ring particles or levitated by electromagnetic forces, and material flowing along magnetic field lines from the rings into the planet.

Cassini spacecraft obtained the images that comprise this mosaic. The Cassini mission was a cooperative project of NASA, the European Space Agency and the Italian Space Agency.
Credit: NASA/JPL-Caltech/Space Science Institute

In addition, the spacecraft will be close enough to the rings for it to feel their gravity, enabling the mass density to be mapped at higher fidelity than previously possible. At the same time, the spacecraft gets close to Saturn itself many times, allowing for repeated measurements of the planet’s asymmetric gravitational field, high-resolution images of its atmospheric clouds, and in-situ observations of the inner magnetosphere.

High-level science

Advocates of a Ring-Skimmer mission suggest it is able to address a wide range of high-level science goals that are relevant not only to Saturn and its rings, but also to giant planets and astrophysical disks in general. Supporters of the idea see it as a potential option for NASA’s New Frontiers program.

A white paper on the concept is to be submitted to the 2023 Planetary Science Decadal Survey.

As for the idea moving from white paper to reality…well, it’s a ring toss.

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