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Image of plumes erupting from Io’s surface taken by NASA’s Galileo spacecraft in June 1997. (Credit: NASA/JPL/University of Arizona)
What can a sample return mission from Jupiter’s volcanic moon, Io, teach scientists about planetary and satellite (moon) formation and evolution? This is what a recent study presented at the 56th Lunar and Planetary Science Conference hopes to address as an international team of more than two dozen scientists discussed the benefits and challenges of a mission to Io with the goal of sampling its volcanic plumes that eject from its surface on a regular basis.
Here, Universe Today discusses this incredible research with Aanu Adeloye, who is a PhD Candidate in Aerospace, Aeronautical, and Astronautical Engineering at the University of Texas at Austin and lead author of the study, regarding the motivation behind the study, significant takeaways, next steps for making a sample return a reality, and the importance of returning Io samples to Earth. Therefore, what was the motivation behind the study?
“This study was sponsored by the Keck Institute for Space Studies (KISS) at the California Institute of Technology as part of a two-part workshop series titled ‘Sample Return from All across the Solar System’,” Adeloye tells Universe Today. “The primary objective was to evaluate both the scientific case for and the feasibility of returning samples from the surface, atmosphere, or plumes of diverse planetary bodies—from Mercury to Kuiper Belt Objects beyond Pluto’s orbit. Through this workshop, we developed a prioritized list of solar system targets for sample return missions over the coming decades, based on expected scientific yield and technological readiness. Io emerged as one of the key targets on this list.”
Image of Io’s nightside and dayside taken by NASA’s Juno spacecraft. (Credit: NASA/JPL-Caltech/SwRI/MSSS Image processing by Emma Wälimäki © CC BY)
For the study, the researchers discussed the reasons behind choosing Io for their sample return mission, vital questions that returned samples could answer about volcanism and Io’s formation and evolution, the mission design, and the scientific impact on the planetary science community. The researchers emphasized how a sample return mission to Io could build off previous spacecraft missions to the Jovian (Jupiter) system, including Galileo, New Horizons (flyby en route to Pluto), and Juno (currently active).
Potential questions a sample return mission could address include Io’s geologic and isotopic composition, plume source and composition, geologic similarities to Europa, and Io’s interaction with Jupiter’s massive magnetic field. For mission design, the researchers propose a fast-moving spacecraft that would travel through the plumes while collecting samples, highlighting the importance of not needing to land on the surface. They estimate the total mission length from launch to return would be approximately 9.4 years based on proposed propulsion technologies. Finally, the researchers emphasized how a sample return mission could help planetary scientists gain greater insight into planetary formation and evolution, specifically Jupiter and its moons. Therefore, what were the most significant takeaways from the study?
“Io stands out as the most volcanically active body in our solar system, boasting hundreds of active volcanoes that emit plumes of gas and dust reaching heights of up to 400 km [250 miles] and spanning widths as large as 1500 km [930 miles],” Adeloye tells Universe Today. “Positioned at the boundary between the outer and inner Solar System, Io occupies a unique location that makes it an ideal target for sample return missions. Analyzing samples from Io promises to shed light on many enduring questions about the origins and evolution of the Solar System.”
NASA missions typically take years, and sometimes decades, to go from a concept to returning relevant scientific data. They are typically designated specific mission types based on budget and scope of the mission, including Discovery, New Frontiers, Solar System Exploration, and large strategic missions (formerly called Flagship). This also includes whether the mission will be a flyby, orbiter, lander, or rover. For this Io sample return mission, the researchers have designated it as a flyby since it will fly through Io’s plumes without stopping and returning to Earth with the collected samples.
Image of plumes erupting from Io’s surface taken by NASA’s Galileo spacecraft in June 1997. (Credit: NASA/JPL/University of Arizona)
The NASA selection process for each mission typically consists of several phases involving concept, designs, testing hardware in a laboratory or ground setting, re-designs, more tests for specific systems, integrating all systems together, more tests, launch, cruise, arrival, and finally data collection. Therefore, what are the next steps for making an Io plume sample return mission a reality?
“The Io sample return study evaluated both the scientific rationale and the technological requirements needed for such a mission,” Adeloye tells Universe Today. “We concluded that, with current technology, a ‘New-Frontiers-style’ mission could feasibly perform a fly-through of one of Io’s volcanic plumes to collect gas and dust ejected from its crust. This concept is achievable using today’s propulsion and sample collection systems.”
Adeloye continues, “Furthermore, our ability to develop sophisticated simulations of Io’s plumes will greatly aid in mission planning and execution. Although further improvements in laboratory techniques are needed to optimize the analysis and yield of returned samples, we expect these challenges to be addressed over time. The next step is to assemble a team of leading scientists and engineers to develop and present detailed concept missions to the scientific community.”
As noted, Io is the most volcanically active planetary body in the solar system, boasting hundreds of volcanoes that eject magma and other materials hundreds of kilometers into space. This volcanic activity results from a phenomenon known as tidal heating, which occurs when the gravity of a much larger body tugs on a smaller body, causing it to stretch and compress during the latter’s orbit. In Io’s case, Jupiter’s intense gravity tugs on the much smaller moon as the latter orbits in an elliptical (oval-shaped) pattern, meaning Io is closer to Jupiter at some points during its orbit and farther away at other points.
Io’s volcanic activity was first discovered by Voyager 1 when it and its sister spacecraft, Voyager 2, conducted flybys of Jupiter and its moons in 1979. This was the first time that active volcanism was observed on another planetary body aside from Earth, opening new understandings into the complex and unique nature of the solar system. Therefore, what is the importance of returning Io plume samples to Earth for further analysis?
“Io occupies a unique position within both the Jovian system and the broader Solar System,” Adeloye tells Universe Today. “Its dynamic, transient atmosphere and vigorous volcanic activity continually renew its surface, effectively mitigating the space-weathering effects seen on more geologically inactive bodies. Consequently, Io's distinctive properties have preserved its surface materials in a relatively pristine state. Collecting samples from Io thus offers an unparalleled opportunity to probe early Solar System materials in a way that samples from more weathered bodies cannot.”
What will sampling Io’s volcanic plumes teach scientists about planetary formation and evolution in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Laurence Tognetti, MSc
Laurence Tognetti is a six-year USAF Veteran with extensive journalism, science communication, and planetary science research experience for various outlets. He specializes in space and astronomy and is the author of “Outer Solar System Moons: Your Personal 3D Journey”. Follow him on X (Twitter) and Instagram @ET_Exists.
You can email Laurence for article inquiries or if you're interested in showcasing your research to a global audience.