This is part of the series of 30 exercises developed during the 3D4KIDS program. One of the aims of this Erasmus+ program is to improve the knowledge of teachers regarding the 3d printing technology by developing some specific training materials. More info in the website: https://www.3d4kids.eu/ The lesson is about designing and printing the Solar system in order to understand and identify the different planets that are part of it, to study their origin and evolution and to explore the space through the planets structure, features and size. It will also serve to learn and to understand the 3D printing technics.