The HORIZON 2020 project BADGER (Robot for Autonomous underground trenchless operations, mapping and navigation) is one of the few funded projects in the last LEIT ICT 25 2016 Call (7,4% of success). The RoboticsLab of the University Carlos III of Madrid (ES) leads the project with the following partners: University of Glasgow (UK), CERTH (GR), IDS Geo (I), SingularLogic (GR), Tracto Technik (D), ROBOTNIK (ES). The main objective of the project is the design and development of the autonomous underground robotic system that can drill, manoeuvre, localise, map and navigate in the underground space, and which will be equipped with tools for constructing horizontal and vertical networks stable bores and pipelines. The proposed robotic system will enable the execution of tasks that cut across different application domains of high societal and economic impact including trenchless constructions, cabling and pipe installations, geotechnical investigations, large-scale irrigation installations, search and rescue operations, remote science and exploration, and defence applications. For this purpose, BADGER will deliver a highly innovative robotic system by integrating research into all required novel technical advances. BADGER will integrate innovative mechatronic concepts with robust industrial drilling tools to yield advanced manoeuvrability and motion capability; will integrate perception, localisation and mapping techniques in order to sense map and interpret the surrounding underground environment; the system will merge collected underground data with legacy digital maps to plan and track the motion of the robot with respect to physical landmarks. The robotic system actions and reactions will be governed by the cognition component which makes decisions on task execution, path planning and motion planning. Its main applications are for trenchless construction of subterranean small-diameter and highly curved tunnels for water & gas pipes, telecoms cables, etc.