Which innovative sustainability initiative was implemented at the European Southern Observatory (ESO) in Chile to significantly reduce its environmental impact?

The astronomy industry faces unique environmental challenges - from light pollution affecting observations to the carbon footprint of massive observatories and space launches. In recent years, major observatories and space agencies have launched various sustainability initiatives to address these concerns. Test your knowledge about how astronomy is becoming more environmentally responsible while still reaching for the stars.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

Installation of a solar farm that provides over 50% of the observatory's daytime energy needs
Development of biodegradable telescope mirror coatings that don't require toxic chemicals
Implementation of water-free cleaning systems for telescope optics
Creation of a carbon-neutral shuttle service using hydrogen-powered vehicles