: 30http://astraiosdb.utwente.nl/data/continuing_education_course/ Create a prefix for http://astraiosdb.utwente.nl/data/continuing_education_course/ Hit Enter to save Double click to create a prefix | : addresshttp://schema.org/ Create a prefix for http://schema.org/ Hit Enter to save Double click to create a prefix | The Conquest of Space: Space Exploration and Rocket Science | edX @en |