In July 2023, planetary scientists from across disciplines and around the world joined representatives of NASA, the European Space Agency, and the Italian Space Agency at the California Institute of Technology. Researchers filled the conference space to capacity, requiring overflow rooms to accommodate the crowd of attendees.
The workshop that sparked this intense interest was “Uranus Flagship 2023: Investigations and Instruments for Cross-Discipline Science.” Although the Uranus system has long been a source of intrigue to planetary scientists, the only spacecraft to actually visit the system was Voyager 2 back in January 1986. Now, almost 40 years later, scientists and engineers are making plans to go back and take another look at the ice giant.
When Voyager 2 performed its flyby of the Uranian system, it returned data on the planet and its rings, major moons, and magnetosphere [Stone and Miner, 1986]. The data painted a picture that was complex, dynamic, and mysterious. This one-time flyby provided a greater understanding of how our solar system formed and evolved and has helped us understand exoplanetary systems as well [Cartier, 2023].
Over the past several decades, an increasing number of planetary scientists have been advocating for a flagship-class mission to explore the Uranian system [Mandt, 2023]. In fact, the latest Planetary Science and Astrobiology Decadal Survey ranked a Uranus Orbiter and Probe (UOP) mission the highest-priority new flagship mission for NASA in this decade [National Academies of Sciences, Engineering, and Medicine, 2022].
Scientists at the Uranus Flagship 2023 workshop took the opportunity to discuss the science opportunities of such a mission, identify potential gaps in the UOP concept, and, perhaps most importantly, identify critical topics for the community and for NASA to address to facilitate a productive, effective, and engaging mission.
A Holistic Look at the Uranian System
Different elements of the Uranian system are intricately linked in predictable and unpredictable ways and require a suite of interdisciplinary measurements to study in depth.
The Uranus Orbiter and Probe concept would investigate all aspects of the Uranus system. Different elements of the system, including the planet’s interior, magnetosphere, atmosphere, rings, and moons, are intricately linked in predictable and unpredictable ways and require a suite of interdisciplinary measurements to study in depth.
At the Uranus Flagship workshop, participants frequently cited the planet’s magnetosphere as an example of the interdisciplinary planetary science required to study the Uranian system. Scientists presented how the magnetosphere provides constraints on the interior structure and composition of Uranus, the surface composition and interior structure of its moons, the potential heating in the Uranian ionosphere, and the transport of mass and energy within the entire system.
Also discussed were specific scientific questions that require an array of interdisciplinary measurements to answer. When thinking about the major moons of Uranus, for instance, a question of interest to the scientific community is whether these bodies may contain subsurface oceans. To answer this, measurements could include induction using magnetometry, static gravity, surface morphology, and libration.
![Montage of the six largest moons of Uranus: Titania, Oberon, Miranda, Puck, Umbriel, and Ariel.](https://i0.wp.com/eos.org/wp-content/uploads/2024/07/uranus-moons.jpg?resize=780%2C694&ssl=1)
In addition to better understanding planetary phenomena, a flagship mission to the Uranian system would contribute to fields including astrophysics, heliophysics, and exoplanet astronomy. For example, most exoplanets known today—mini-Neptunes, sub-Neptunes, and hot Neptunes—are approximately the size of Uranus and Neptune, so understanding Uranus is critical to our understanding of exoplanetary systems.
Present Considerations for Future Science
Although the UOP mission is still in the early phases of planning, it is critical for the community to think about what current activities would benefit the future science of the mission.
To identify the most important measurements and instrumentation for the spacecraft, workshop attendees stressed that telescopic observations and laboratory measurements can be undertaken now, during mission development. Telescopic observations, including those by the James Webb Space Telescope (JWST), Hubble Space Telescope, and Keck Observatory, can be used to help formulate scientific questions and influence instrument design before instruments are selected.
Observations could also reduce risk to the UOP spacecraft. For example, JWST can help identify potential hazards posed by material between the innermost currently known ring of Uranus and the planet itself, an area the spacecraft is currently proposed to fly through.
Additionally, although the UOP mission is still in development, critical laboratory measurements could be made that would improve instrument design and increase scientific understanding. Such measurements include the behavior of cryogens associated with the major moons; spectroscopy of materials expected to be present on the planet, moons, and rings; and the behavior of high-temperature, high-pressure materials that would be relevant to the interior of Uranus.
![A cutaway drawing of the interior of the planet Uranus](https://i0.wp.com/eos.org/wp-content/uploads/2024/07/uranus-interior.jpg?resize=780%2C546&ssl=1)
Theoretical studies are also needed to help plan for the UOP mission. Improvements to our understanding of many processes such as planetary formation, the planetary dynamo, atmospheric dynamics, ring and embedded moon dynamics, and magnetospheric reconnection events could be used to guide science prioritizations, measurement requirements, and mission design.
Although making payload recommendations was beyond the scope of the Uranus Flagship 2023 workshop, we note that three orbiter instruments were presented for discussion that were not previously studied for UOP: a dust composition analyzer, a mass spectrometer, and an X-ray detector.
Attendees noted that the dust analyzer and mass spectrometer could benefit interdisciplinary science by providing insight into the composition of rings and moon surfaces, increasing our understanding of material produced through magnetospheric weathering, and measuring mass exchange between different components of the Uranian system. Additional instrumentation to the UOP concept, however, would need further, more comprehensive study, for example, from premission observations, to better evaluate the benefits to science versus increased cost to the mission.
An Opportunity to Diversify the Scientific Community
Participants at the Uranus Flagship 2023 workshop recognized the mission’s unique opportunity to grow the diversity of the scientific community.
At this early stage in the process, it is of critical importance to address the human challenges posed by a flagship mission to Uranus. By discussing the diversity, equity, inclusion, and accessibility (DEIA) of a mission that will span decades, participants at the Uranus Flagship 2023 workshop recognized the mission’s unique opportunity to grow the diversity of the scientific community as a whole.
Two focus areas for the development of a UOP mission addressed at the Uranus Flagship 2023 workshop were therefore DEIA and advocacy for early-career scientists.
Updating the traditional science team model presents a prime opportunity to expand access to science team roles and enhance inclusion efforts. At present, early-career scientists who do not work either at a NASA center or with a limited number of senior Uranus researchers do not have a clear path to becoming involved with a Uranus mission. This lack of access should be addressed now because it can take years to make any notable progress in mission infrastructure processes.
The Dragonfly Student and Early Career Investigator Program is setting a precedent. The initial phase of the program, affiliated with the NASA mission to send a spacecraft to Saturn’s moon Titan, began in 2020. It targets potential new investigators who are not affiliated with Dragonfly or other spacecraft missions [Quick et al., 2020] and has been highly successful in achieving participation from people who would not have been involved otherwise. A Uranus mission could learn from this program and should start actively recruiting a diverse set of scientists and students as soon as possible.
Highly active and influential affinity groups like Black in Astro [Walker et al., 2023] present another huge and largely untapped potential for collaboration in a UOP mission. Not only do these groups include highly skilled individuals who may not otherwise get involved in a mission, but they also offer varied models of communities that practice inclusion and access as a matter of course.
Mentorship programs also provide a way to increase inclusion and will be vital in fostering the intergenerational work [Rathbun et al., 2020] necessary for a successful UOP mission. Pairing early-career individuals with more senior researchers or engineers can help knowledge exchange and transfer across generations, preventing the loss of skills over the mission lifetime.
NASA and other large organizations need to develop practices that create opportunities for early-career scientists and engineers from underrepresented communities to get involved in the mission from the start, expanding beyond current programs, such as NASA’s Here to Observe, that target only undergraduate students. As part of this effort, it is critical to fund the professional organization of, and participation in, DEIA activities. A lack of inclusion practices in early-career organizations ultimately affects retention in the field and, over time, creates a loss of expertise that is needed for a mission with a long lifetime.
Organizations need to implement practices to ensure that the best people work and continue working on long-scale projects [e.g., Clancy et al., 2017; Richey et al., 2019]. Such practices include implicit bias training and bystander intervention training for mission teams. Written resources and education on policies must be in place to prevent harassment; such proactive measures will, in turn, support retention and inclusion by creating and maintaining a safe work environment. Trained social scientists should collect demographic data and workplace climate surveys to consistently monitor inclusion and accessibility throughout the entire mission lifetime.
Building a Community to Build a Mission
The Uranus Flagship 2023 workshop was an important start for bringing the scientific community together to work toward the most successful implementation of a future Uranus mission. There is a long road to travel, and the community should continue to meet every 1 to 2 years. The community is already embracing this cadence with the 2024 Uranus Flagship workshop held at NASA Goddard.
The potential for interdisciplinary science was one of the reasons a spacecraft to the Uranus system was ranked as a high priority by the Planetary Science and Astrobiology Decadal Survey.
The workshop was effective for community discussion and collecting input, but ultimately, a workshop cannot replace a dedicated UOP Science Definition Team (SDT) to determine priorities, objectives, mission architecture, science investigations, and instrument payload. It is important to the scientific community that NASA utilize an SDT or SDT-like process, with potential modification to maximize the inclusion of diverse groups, including early-career scientists and those with minoritized identities [Rivera-Valentín et al., 2021].
The potential for interdisciplinary science was one of the reasons a spacecraft to the Uranus system was ranked as a high priority by the Planetary Science and Astrobiology Decadal Survey. The Uranus Flagship 2023 workshop started engaging researchers to discuss the science, as well as investigate critical topics for the community and NASA to focus on in the coming years. The enthusiasm of workshop participants similarly extended to both the transdisciplinary nature of the mission and establishing DEIA strategies and support for early-career scientists as integral to its long-term success.
Acknowledgments
We thank the members of our DEIA panel, Ashley Walker (Howard University), Christina Richey (Jet Propulsion Laboratory), and Elizabeth Turtle (Johns Hopkins Applied Physics Laboratory), for their invaluable insight. We thank the Local Organizing Committee, Paul Schenk (Lunar and Planetary Institute) and Katherine de Kleer (California Institute of Technology), and the Science Organizing Committee, Athena Coustenis (Centre National de la Recherche Scientifique), Richard Dissly (Ball Aerospace), Catherine Elder (Jet Propulsion Laboratory), Leigh Fletcher (University of Leicester), Matthew Hedman (University of Idaho), Jonathan Lunine (Cornell University), Kathleen Mandt (NASA Goddard Space Flight Center), Olivier Mousis (Laboratory for Astrophysics in Marseille), Francis Nimmo (University of California, Santa Cruz), Carol Paty (University of Oregon), Naomi Rowe-Gurney (NASA Goddard Space Flight Center), Amy Simon (NASA Goddard Space Flight Center), Krista Soderlund (University of Texas Institute for Geophysics), and Paolo Tortora (University of Bologna). We thank the California Institute of Technology for hosting and the Lunar and Planetary Institute for organizational support. We thank the Jet Propulsion Laboratory, California Institute of Technology, for supporting the workshop. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA (80NM0018D0004).
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Author Information
Erin J. Leonard (Erin.J.Leonard@jpl.nasa.gov) and Mark Hofstadter, Jet Propulsion Laboratory, California Institute of Technology, Pasadena; Naomi Rowe-Gurney, Royal Astronomical Society, Wallingford, U.K.; and Jamie M. Jasinski and David Atkinson, Jet Propulsion Laboratory, California Institute of Technology, Pasadena