End-to-end mission performance simulators for Earth Observation missions are one of the prominent tools for system design and scientific validation in early mission phases. The European Space Agency (ESA)has promoted efforts to exploit synergies between activities and reduce engineering costs. Some of these activities are the ARCHEO study, the BIBLOS project, the OpenSF frameworkandthe EO CFI library, the. The main goal of BIBLOS is to provide a library of software units called “Building Blocks”, or simply “Blocks”,that can be used to build an end-to-end simulator. Many Blocks are common across simulators, for example the geometry-related ones. Some Blocks are common for a certain type of instrument, like the Radiative Transfer Model, or parts of theInstrument model. BIBLOS targets the Blocks mostfrequently used by the engineering and scientific community. The user can access the library through the BIBLOS website, download the Blocks and use them directly, in combination with their own developments, or modify them. All of the Blocks are provided with the source code, and are under ESA Software Community License. The first stage of this activity focused on Passive Optical instruments, mainly imagers, which are one of the most frequent types of instrument on Earth Observation satellites. The models already developedinclude the geometry, scene generation and instrument modelling of an optical imager. These Blocks can be combined into a full chain that produces raw data. ESA is currently developing the Level-1 processing, which may be includedinto BIBLOS in the future. Themodels, documentation and demos can be downloaded from the BIBLOS website: https://gmv-biblos.gmv.com/.A second stage of the activity is currently ongoing with the purpose of expanding this library to include Passive Microwave instruments and Active Microwave instruments. Severalsimulators for Passive and Active Microwave payloads are currently being developed for ESA missions and it is foreseen that more will follow in the near future. Therefore, BIBLOS has the potential of supporting these developments.Additionally, as part of a continuous improvement process, this second stage of BIBLOS will also update some of the most computationalperformance intensive blocks for Passive Optical instruments with parallel implementation for Graphic Processing Units.This paper presents the work carried out for the second stage of the BIBLOSactivity

Peer Reviewed