Science objectives of ESA's Genesis mission: a flying geodetic observatory to improve ITRF accuracy and stability 

Genesis is an ESA mission in preparation within the Navigation Directorate under the FutureNAV Programme, dedicated to advancing space geodetic science and the International Terrestrial Reference Frame (ITRF). It co-locates GNSS, SLR, DORIS, and a pioneering VLBI transmitter on a single satellite in near-polar orbit (~6000 km), creating a dynamic space geodetic observatory that delivers well-calibrated space ties between all techniques.These co-located measurements enable rigorous integration of space-geodetic techniques, revealing and mitigating inter-technique biases that currently limit ITRF scale, origin, and orientation. The Genesis objectives demand a stable and well-characterised platform as well as rigorous calibration of instruments and antennas, including phase/group delays and phase center offsets. The mission's novelty and methodology at mm-level demand also the careful preparation of observation strategies and adoption of data analysis and combination techniques for Genesis data exploitation.Here, we present an overview of the ongoing activities relevant to the science community and ITRF realisation, including the scientific objectives and the status and plans of science instruments and calibrations. The scientific datasets and expected data products, along with their planned availability to the scientific community, will also be discussed.