ÌÇÐÄÊÓƵ

Exploring Titan's icy hydrocarbon cycle

Though wildly different in so many ways, Earth and Saturn's moon Titan have something important in common. Among all the objects in the solar system, they're the only two with liquids on their surfaces. There are parallels in how the liquids move in cycles on both worlds and a new mission proposal outlines how we can understand Titan better by studying these parallel processes.

Scientists are proposing a new mission to Titan called LOOKING GLASS, which is inspired by a recent decadal survey. The is called "Mission Concept LOOKING GLASS: Exploring Titan as Earth's Dark Mirror," and it was presented at the recent 2025 Lunar and Planetary Science Conference. The lead author is Dr. Rutu Parekh from NASA's Jet Propulsion Laboratory.

"Saturn's largest moon, Titan, stands out as a dynamic, icy oceanic world featuring Earthlike hydrocarbon reservoirs that cycle through its atmosphere, surface, and interior," the authors write. Titan's atmosphere also creates complex organic molecules that could sink into the moon's subsurface oceans and form prebiotic chemistry. While previous research has uncovered all of this, what's missing is an understanding of how all of this is connected, just like the understanding of Earth's systems that science has uncovered. LOOKING GLASS is designed to do just that.

"The expected results from our proposed mission will also raise additional questions about the relationships between these processes, in turn providing the central focus of our proposed mission concept," the researchers explain.

In LOOKING GLASS, a spacecraft would follow a low-altitude circular orbit around Titan and study the moon's subsurface, surface, and atmospheric processes in detail. Scientists want to find out if its hydrocarbon lakes are connected underground, allowing materials to be transported between them, or if they're fed by precipitation. They want to know how fluvial channels and dunes form. They want to understand how short-term and long-term climatic factors affect the moon's aeolian processes.

There are other questions in need of answers, too. What drives the changes in Titan's stratospheric ice clouds? Which surface flow features are fluvial, and which are cryovolcanic? Previous research shows that Titan's possible cryovolcanic activity shapes the moon's surface and could help replenish the methane in the atmosphere. How does that work? Models show that the moon may harbor a layer of high-pressure ice at the bottom of its subsurface ocean. Is it really there?

Proponents suggest three instruments for LOOKING GLASS:

• An infrared spectrometer to analyze surface composition and distinguish between materials like water ice and hydrocarbons to determine if surface and subsurface methane reservoirs are interconnected, to detect cryovolcanism, and to study the nature of fluvial erosion.
• A synthetic aperture radar (SAR) to provide high-resolution images of the moon's surface, identify and characterize subsurface hydrocarbon reservoirs, and study fluvial and cryovolcanic features and aeolian dunes.
• A radar altimeter to measure Titan's surface topography and build our understanding of lake elevations, fluvial channel slopes, and Titan's ice shell thickness and convective state.
• X and Ka-band transponders that serve two purposes. They allow communication with Earth from such a great distance. They also allow gravity science, which can help scientists understand the thickness of the subsurface ocean.

These instruments will work together to paint a much clearer picture of Titan's intricate methane cycle, atmospheric dynamics, complex surface processes, and internal structure.

Titan is a fascinating world that's unique in the solar system. Scientists have wondered if some strange type of life could exist there that uses liquid hydrocarbons rather than water. The idea hasn't gained much traction, but it illustrates how complex and interesting the moon is.

A better understanding of this complicated world will help us understand what's possible and what kind of worlds Nature can generate. "Data from the proposed mission could revolutionize our understanding of the methane cycle, cryovolcanic activity, organic chemistry, and the potential for life beyond Earth," the authors write.

"A New Frontiers-class Titan remote sensing mission has the capability to unlock some of the most profound mysteries of our solar system. Mysteries with implications regarding the provenance of volatile compounds and even life on our own planet," the authors conclude.