EnVision Science Operations Activities: Targeted observation scenario

EnVision's scientific goal is to study Venus from its core to its atmosphere, focusing on the planet's history, activities, and climate [EPSC2026-XXX]. The mission seeks to understand Venus' geological evolution, current geodynamic state, and interactions with its atmosphere. Additionally, EnVision will search for signs of past liquid water on Venus' surface.

EnVision will orbit Venus at a low-altitude on a quasi polar orbit for 6 Venus years or cycles (~ 4 Earth years). Through this nominal science phase, the mission will create comprehensive global maps of the surface [EPSC2026-XXX] but a crucial part of addressing the science objectives will be to observe high value targets from diverse types of terrains to help piece together its history. To that end, the EnVision science team has been working on a list of regions of interest to be observed with EnVision’s Synthetic Aperture Radar instrument and the Subsurface Radar Sounder.

The data generation is relatively high for a planetary mission, varying between 70 and 350 Gbit/day and the data downlink rates vary by a factor of 10 during a synodic period. Full SAR coverage cannot be achieved within the 6 Venus cycles, and coverage distribution will be dependent on the arrival date. The observing plan and hence location of observations must be adapted to the allowed data rates; observations with higher data rates such as SAR polarimetry or high resolution observations, can only be planned at certain times.

At this point in the mission development, a lot of uncertainties remain which is why we are working on reference Science Operations Scenarios to ensure the mission science objectives can be met.

The challenge of balancing the data generation, storage and downlink, means that not all potential targets can be observed and selection and prioritization is required [EPSC2026-XXX]. The SAR observations have requirements on viewing angle and overlap for repeat observations (stereo), and change detection measurements (requiring three observations), thus further limiting the opportunities to observe targets. This has been a particular focus of the EnVision science team as well as the ESA science planning team, who aim to demonstrate that the coverage in area and target type meet the mission’s objective.  In this presentation, we want to break down the different operational challenges we are facing for planning targeted observations with EnVision and how our Reference Scenario addresses them to ensure mission success.

References:

[1] ESA BR-247, Cosmic Vision, Space Science for Europe 2015-2025, [2] Straume-Lindner et al. (EPSC2026-XXX), [3] Eckstein et al. (EPSC-DPS2025-1637), [4] ESA (2021), “EnVision, Understanding why Earth’s closest neighbour is so different”, Definition Study Report for the mission adoption ( Red Book), [5] Maiheux et al. (EPSC2026-507), [6] Mason et al. (EPSC2026-XXX).