A novel radiometer for clouds investigations in future Venus aerobot missions

The history of in-situ Venus exploration has been limited to a few opportunities with different probes that were capable to operate, for short periods of time, under the extreme atmospheric conditions of the planet. Among these missions, the VeGa balloons deployed in the Venus atmosphere in the mid-eighties of previous century revealed the advantages of using this concept for investigating the atmosphere of Venus. In this regard, the recent studies for the 2023-2030 Planetary Decadal Survey [1-3] have pointed the potential of using balloon platforms for planetary science exploration, considering that the different technologies required for these missions are currently mature enough to develop long-lived and possibly even altitude-varying probes or more specifically, aerobots.
In this work, we present an early concept of a lightweight radiometer for future balloon missions to Venus. Its primary scientific objectives are: i) to measure solar and ii)thermal infrared fluxes and their deposition in the cloud layer, iii) to characterize the variability of the cloud structure and its constituents, and iv) to detect and characterize atmospheric lightning events. Those investigations will allow us to understand the role of each objective in determining the atmospheric structure and the driving circulation of the planet.
Due to the limitations on resources for this kind of platforms, the key characteristics of the proposed instrument are its high scientific performance and the scarce resources needs: low accommodation volume, size, and mass; low power and data volume consumption. The radiometer combines different spectral bandpass channels (from UVA to IR) with particular orientations and field of view (FoV) selected to meet the scientific objectives. The instrument also incorporates a visible camera to provide context images for cloud investigations.
The Spanish National Institute of Aerospace Technology (INTA) has established a long-term strategy in the last decade with the program InMARS [4] that is devoted to developing high-performance, low-power, miniature sensors designed for in-situ planetary missions [5-10]. Within this program, we have developed an intensive selection, qualification, and screening activity in our particular technological roadmap called CERES (Compact Electronic Resources for the Exploration of Space), which allowed INTA to acquire critical technologies, components (including mixed ASICs [11-12]), materials and procedures for such instrumentation developments.

[1] K.H. Baines et al, 2020. White Pape. [2] Martha S. Gilmore et al, 2020. Venus Flagship Mission Decadal Study Final Report [3] Joseph O’Rourke, ADVENTS misión concept study. [4] I.Arruego et al. IPPW 2018. Boulder. Colorado. USA. [5] H. Guerrero et al. EGU 2010. Geophysical Research Abstracts Vol. 12, EGU2010-13330, 2010. [6] I. Arruego et al. DREAMS-SIS. ASR 2017. 60 (1): 103-120. [7] V. Apéstigue et al. Sensors.2022. [8] D. Rodionov et al. Sixth International Workshop on the Mars Atmosphere: Modelling and Observations. 2017. Granada. Spain. [9] D. Scaccabarozzi et al. IEEE MetroAeroSpace proccedings. 2019. Torino.Italy. [10] A. Russu et al. Proc. SPIE 11129. [11] S. Sordo-Ibáñez et al. IEEE Transactions on Nuclear Science, vol. 63, pp. 2379-2389, 2016. [12] S. Sordo-Ibáñez et al. IEEE Transactions on Magnetics, vol. 51, pp. 1-4, 2015