Sixth International Planetary Dunes Workshop

The 6th International Planetary Dunes Workshop (#planetarydunes2020) was held virtually on May 12–13, 2020. The workshop provided a forum to discuss the current state of planetary aeolian science and the needs for the next decade. Contributions were on such topics as remote sensing, analog studies, laboratory experiments, and computer modeling results.

The workshop was originally planned to be a physical workshop to be held in Alamosa, Colorado, on May 12–15, 2020. Due to travel restrictions and the need for social distancing resulting from the COVID-19 pandemic, the organizers decided to postpone the physical meeting by one year. However, one objective of the meeting, which was to support and facilitate planetary aeolian community input into the forthcoming Planetary Science and Astrobiology Decadal Survey, could not be delayed. With this consideration in mind, the organizers decided to move forward with a shorter virtual version of the workshop. The focus of the first day was the current state of planetary aeolian science and the second day’s focus was identifying knowledge and capability gaps. Both days were limited to 4.5 hours of presentations interspersed with several discussion periods and breaks.

The first day was broken up into three mini-sessions: (1) Dynamics, (2) Bedforms, and (3) Geological Record. The second day was also broken up into three mini-sessions: (1) Analog and In Situ Studies, (2) Mission, Models, and Technology, and (3) Facilities and Data Archival. Following the presentations on day 2, workshop attendees divided into three small group discussions, with each group focusing on one of the mini-session topics. At the end of day 2, key messages from these small group discussions were shared with the full group. Each group was specifically asked to address three questions: (1) What are the strategic knowledge gaps? (2) What are the strategic technology/capability gaps? (3) What are the mission/spacecraft gaps?

A workshop highlight was the discussion of analog sites and the expansion of what is considered a planetary analog site. For example, terrestrial subaqueous processes and bedforms are thought to be possible analogs for planetary bodies with thick, dense atmospheres (e.g., Venus, Titan), and the processes and bedforms within Mars’ low-density atmosphere may serve as better analogs for features on some planetary bodies (e.g., on small bodies or icy worlds) than terrestrial examples.

Additionally, it seems feasible for in situ studies on Mars to be sufficiently comprehensive to serve as “natural laboratory” studies for understanding the fundamental physics of aeolian processes throughout the solar system by providing controlled non-terrestrial conditions. A crucial complement to such studies are experiments run within planetary aeolian facilities, which provide validation for planetary aeolian models and constrain input parameters. The need for continued support and possible expansion of existing planetary aeolian facilities was deeply discussed.

The spacecraft mission presentations focused on the use of drones on other planetary bodies, starting with the Mars Helicopter and the Titan Dragonfly spacecraft. The participants agreed that the use of drones is potentially a game-changing technology for understanding surface-atmospheric interactions as recorded by aeolian bedforms and erosional landscapes. Drones have the potential to provide in situ analysis at larger ranges than traditional rovers. Drones could also sample the interior of dune fields without the trafficability issues (e.g., getting stuck in the sand).

For Mars, a greater understanding of the dust cycle is needed as current models are unable to accurately predict when global dust events will occur. Dust lofting and how that dust affects surface and atmospheric dynamics are also poorly understood. An improved understanding of these processes would improve models, which currently are often empirically parameterized and carefully “tuned” to match observations of a particular year. Without improved theoretical knowledge and a more rigorous grounding of the model, it is difficult to properly “tune” the model for forecasts for spacecraft safety or to predict what changes would occur under different Mars obliquities.

Finally, several attendees agreed that a Planetary Aeolian Processes Goals document was needed. Such a document could be modeled after the NASA Analysis and Assessment Groups’ goals documents.

For more information about the 6th International Planetary Dunes Workshop, including links to the program and abstracts, visit the meeting website at https://www.hou.usra.edu/meetings/dunes2020/.

— Text provided by T. Titus (USGS) and S. Diniega (JPL/Caltech)