Astronaut Paolo Nespoli joins Space Boffins Sue Nelson and Richard Hollingham for a podcast special recorded at the European Space Agency's ESTEC facility in The Netherlands during their Open Day. Thousands of people travel from across Europe and beyond to see where the European Space Agency tests its spacecraft before launch and the birthplace of many of its science missions. Joining the ever entertaining Nespoli on the Space Rocks stage is space debris expert Luisa Innocenti, head of ESA's Clean Space Office, on better alternatives for spacecraft materials plus trainee aerospace engineer Marta de Oliveira, who is working on a proposed future mission to Venus called EnVision.