The objective is to develop a multi-model informed predictive tool of atmospheric parameter variability for mission design and operation.Targeted Improvements:- Enabling a new European tool allowing prediction of atmospheric conditions (e.g., density, composition, radiation) over time, including local state and total dose.- To reduce initial mission design margins hence avoiding overdesign.Description: The recent loss of several communication satellites in low Earth orbit has been linked to an increased atmospheric drag at low altitude, seemingly caused by a minor geomagnetic storm on 3-4 February 2022. The increase in upper atmosphere density during geomagnetically active periods is a well know phenomenon, however it is particularly troublesome for the early phases of spacecraft commissioning that rely on a very low altitude (e.g., 210 km) initial orbit. To date, for general design purposes, the ESA Space Environment Information System (SPENVIS) includes various Earth atmosphere and wind models (NRLMSISE-00, MET-V2.0, DTM78, HW93), some of which also consider geomagnetic activity. While several upper-atmosphere models (above cited plus e.g., DTM2013, JB2008, DFP-ATM, TIE-GCM etc.) co-exist based empirical/physical approaches, there is to date no comprehensive database of atmospheric and thermospheric parameters allowing capture of intra- (local time, seasonal, solar and magnetospheric inputs-driven) and inter-model variabilities, in order to derive better informed engineering margins.This activity will review the existing state of the art models of the upper atmosphere, including preferably coupling effects between the thermosphere, the ionosphere and magnetosphere (heating due to energetic particles, solar flux, ions/neutrals coupling processes), and derive a method to build model-based, time-dependent, 3D atmospheric parameter snapshots in order to establish a database of relevant parameters (at least species densities, temperatures asa function of altitude), as well as their variabilities over different timescales relevant to mission design and planning (e.g. daily to seasonal) as a function of local time and latitude. A user interface will be developed to allow interrogation of the database and to facilitate its use for mission design and planning. The new database shall be tested and validated against existing satcom mission scenarios and data, including observed atmospheric parameter averages and variations over the mission lifetime. Resulting recommendations for the design of satcom mission as well as recommendations for the design at satellite level shall be identified The new database and user interface shall be a prototype of a forecasting tool for identifying relevant inputs and data for future real time applications. The feasibility of developing a modular open-source software based on community input data to improve the accuracy of the predictions shall be studied and guidance for further developments shall be provided. The end database and user interface shall be delivered under an ESA Software Community Licence, so that any individuals or entities within the ESA Member States can accessit and can provide updates to the community of users.

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