Goals and Structure of Envision’s VenSpec Ground-Based Observations Working Group

EnVision is an ESA mission to Venus that will orbit Venus in 2034 and aims to provide a holistic view of Earth’s sister planet from its inner core to its upper atmosphere [1]. The mission is developed in partnership with NASA and has science goals that address the study of the planet’s geologic history, its current geologic and atmospheric active processes and the evolution of its interior, surface and climate as a coupled system. To address these goals, EnVision will be placed in a low altitude polar orbit that will allow the mission instruments to acquire data of the planet, its surface and atmosphere at exquisite spatial and spectral resolution. EnVision’s instruments include a suite of three spectrometers grouped together in the VenSpec suite [2]: VenSpec-U (190-380 nm) [3], VenSpec-H (1.16-2.48 µm) [4] and VenSpec-M (0.79-1.51 µm) [2]. The VenSpec suite will map trace gases and atmospheric chemistry, search for volcanic gas plumes above and below the clouds, map surface emissivity and composition and will investigate Venus atmosphere and surface emissivity and composition.

The Venus Ground-Based Observations Working Group has been established in support of EnVision and its VenSpec instrument with the objective of enhancing the scientific return of the mission through coordinated Earth-based observations. The goals of the Working Group are: (1) To provide spectroscopic data that will be useful to test observation strategies and retrieval pipelines with the VenSpec instrument, across the whole range of available wavelengths that can be used to characterize Venus atmosphere and it surface. (2) To coordinate the monitoring of Venus atmosphere, its dynamics and its variability providing knowledge about the evolution of atmospheric features and the global characterization of the atmosphere in the decade since Akatsuki to EnVision. (3) To support and prepare for Venus observations during Envision’s science phase in 2035 and onwards, providing context to the observations that will be acquired by Envision and its VenSpec instrument. 

Examples of current and planned Venus observations and monitoring include observing campaigns with ground-based telescopes such as the Canadian France Hawaiian Telescope (CFHT), NASA’s IRTF or ALMA among others. Members of the WG also run frequent observing campaigns at Calar Alto Observatory and plans for long-term monitoring of Venus with Earth-Orbit CubeSats [5]; and contributions from amateur astronomers providing spatially resolved observations of Venus clouds and surface.

We here explain the structure of the working group, the open channels for information sharing, and the potential time lines for observing campaigns. This presentation is an open call to the community to provide Venus observational data and to join the Working Group.

References: [1] Widemann, T., Straume Lidner, A. G., Schulte, M., and Pacros, A.: Science objective and status of the EnVision Mission to Venus, EGU General Assembly 2025, EGU25-21105, https://doi.org/10.5194/egusphere-egu25-21105, 2025. [2] Alemmanno et al. Synergistic Observations of Venus’ Surface and Atmosphere: The Role of VenSpec on the ESA EnVision Mission (2025, this meeting). [3] Marcq et al. (2025, this meeting). [4] Robert et al. (2025, this meeting). [5] Lee, Y. J.: Long-term Monitoring Plan of Venus using Earth-orbiting CubeSats.Europlanet Science Congress 2024, id. EPSC2024-158, 2024