Measuring the Cosmic Redshift Drift with the VLT: A Long-Term ESPRESSO Program into the ELT Era

The arrival of the ELT in the coming decade will reshape the scientific landscape, but it will also open unique opportunities for the VLT. With the gradual decommissioning of current instruments, we expect that significant observing time will become available for ambitious, time-intensive experiments that are difficult to accommodate today. I will present our vision for exploiting this opportunity by dedicating all dark time of a single VLT Unit Telescope (∼1000 h/yr) to a focused, long-term ESPRESSO program targeting a small set of seven bright quasars. Such a program, started with a limited integration time in 2022 (∼22h) to test systematics and scaling predictions, has the potential to deliver the first direct detection of the cosmological redshift drift by 2080, probing the expansion history of the Universe in a model-independent way. The impact of this project can be accelerated by exploiting synergies with ANDES at the ELT through coordinated parallel observations. These complementarities would not only enhance the sensitivity of the drift measurement but also provide as a legacy a powerful framework for addressing instrumental systematics, data reduction strategies, and cross-facility data combination as well as unique high quality QSO spectra. In this talk, I will outline the scientific rationale, observational requirements, and instrumental opportunities, highlighting how the VLT can remain at the forefront of fundamental cosmology well into the ELT era and beyond.