The evolution of SAR has shown a clear trend towards higher performance at lower cost, less mass, size and power consumption imposing strong requirements in the today’s antenna technology since larger antennas means complex, bulky, difficult to route RF harness, and strong mechanical and thermal requirements for in-orbit deployable antennas. Larger bandwidths associated with larger antennas and scanning angles requires True-Time-Delay (TTD) beamforming, resulting in bulky and complex solutions.The use of photonic integrated circuits (PIC) technology in the beamforming is a clear key enabling technology due to TTD can be implemented by using integrated photonics achieving order-of-magnitude improvements in size and mass, antenna system integration and reduction of the risks associated to the in-orbit antenna deployment. The aim of GAIA is the development of the photonic technology required in future array antenna systems for SAR applications, covering from the optical signal distribution to the antenna, the true-time-delay control of the signal for each antenna element by using integrated photonics (PICs) both in transmission and reception, the design of the optical harness suitable for large, deployable antennas and the development of an antenna array module in X band.GAIA goals establish a significant progress beyond the State-of-the-Art in antenna technology for SAR applications, improving the figures of size-mass-cost and achieving the call objective of compact RADAR / SAR technology for future Earth observation missions and strengthening the European leading in GMES.The consortium has been specifically designed for maximizing the project success since all the actors of the value chain, from photonic technology design and fabrication, institutions with capabilities in technology development and packaging, a subsystem integrator, a system integrator to a final user, most of them with demonstrated experience in space.