Objective:The objective of the activity is to design, manufacture and test integrated entangled photon source and faint pulse source for space Quantum Key Distribution. The high level integration combines low mass, volume, and higher reliability and is therefore ideally suited for space applications. The expected output of the activity is an engineering model of an entangled photon source and a prototype faint pulse source, which have been evaluated for their application in space environment.Targeted Improvements:90%reduction in mass and volume. Improved resistance to mechanical stresses. Potential mass production techniques leading to high reproducibility, lower costDescription:Current developments of photon sources for QKD in space are based on the translation of laboratory breadboards into bulk-element space compatible systems. Following the trends from the ground based developments large scale integration is pursued for improved performance, miniaturisation, mass production and integration. Previous ESA sponsored activities demonstrated the viability of these technologies, but the required performance could not be achieved in terms of brightness and quality of entanglement. In recent years and especially with the ongoing developments in the field, those limitations have been overcome. A complete European ecosystem of developers is now well established and supported by National and European technology programs. This successful development needs to be implemented at space segment level where space compatibility of the materials, integration and packaging processes shall be investigated. In the proposed activity the current push towards performance, integration and reliability driven by the ground applications will be harnessed to shoehorn these techniques in a space-minded design and demonstrate its space worthiness and technological readiness. The activity comprises an initial design of a faint pulse and an entangled photon sources, 2 foundry rounds and testing in a relevant environment.