Pascal Ballester is Head of the Science Operations Software Department at the European Southern Observatory. He joined ESO in 1990, to integrate the Image Processing Group for the development of instrument-related software in MIDAS. He coordinated several projects for the Very Large Telescope, including data reduction software for the high-resolution spectrograph UVES of the Very Large Telescope, the ESO Exposure Time Calculators, and Data Flow System for the VLT Interferometer. As of 2007, he led the ESO Pipeline Systems Department, responsible for the development of data reduction software and observation preparation models for the VLT and ALMA facilities. Since 2014, he is Head of the Science Operations Software Department, providing software development and engineering support to the ESO Programmes, mainly Paranal Instrumentatioon, VLT and ALMA science operations, and ELT programme.