The Extremely Large Telescope (ELT), developed by the European Southern Observatory (ESO), will be the largest optical and infrared telescope ever built, with a 39-meter segmented mirror. This groundbreaking facility aims to transform our understanding of the Universe and offers significant opportunities for Spanish science and industry in advanced technological and engineering fields. 

The High Angular Resolution Monolithic Optical and Near-infrared Integral Field Spectrograph (HARMONI), a first-generation integral field spectrograph (IFS) for the ELT, is designed to deliver diffraction-limited imaging and spectroscopy, enabling unprecedented insights into e.g. the formation and evolution of galaxies, stars, and planetary systems. HARMONI presents strong synergies with other observatories like ALMA and the JWST. 

HARMONI is being developed by an international consortium formed by the University of Oxford, the Astronomical Technology Centre (UK), the University of Durham (UK), the Centre de Recherche Astrophysique de Lyon (France), the Laboratoire d'Astrophysique de Marseille (France), the Instituto de Astrofísica de Canarias (IAC, Spain), the Centro de Astrobiología (CAB/CSIC, Spain), and the University of Michigan (USA). This collaboration combines expertise in astrophysics, engineering, and instrumentation to create one of the most advanced tools for ground-based astronomy. 

Spanish participation, through the IAC and the CAB/CSIC, is pivotal to the development of this complex instrument. The Spanish teams are responsible for essential subsystems, such as the pre-optics, the control electronics, and the calibration systems, which are vital to achieving the instruments scientific objectives. This participation secures Guaranteed Observing Time (GTO) on the ELT, providing valuable opportunities for the Spanish scientific community. In recent years, the HARMONI consortium has faced delays in advancing the final design and increasing resource demands, prompting the HARMONI Executive Board to initiate a comprehensive project scope review. 

This coordinated proposal aims to support the IAC and CAB teams during this critical rescoping phase, addressing technical and organizational challenges while ensuring progress toward HARMONI's successful development. The project also emphasizes scientific preparation, including mock observations, calibration plans, and simulations to refine operational strategies. These efforts ensure access to the guaranteed observing time granted by ESO as compensation for the Consortium's contributions. 

Aligned with national and international strategies for advancing astrophysics and technology, this proposal reinforces Spanish leadership in astronomical instrumentation and strengthens Spains position within the ESO framework.