ABSTRACT
National Aeronautics and Space Administration's (NASA) 2015 Astrobiology Strategy, the European Space Agency's 2016 Astrobiology Roadmap, and NASA’s 2008 Astrobiology Roadmap articulated Themes, Research Topics, and Goals, respectively. Each of the documents delineated a sequence of investigations that addresses the progression of developments leading to the origins of life and its subsequent evolution. This chapter provides a concise yet moderately detailed guide to the National Academy of Science (NAS) and European Astrobiology Roadmap (EAR). It summarizes principally the research objectives recommended by the NAS and EAR. In order to understand how life can begin, it is essential to know what organic compounds might have been available and how they interacted within planetary environments. Interesting organic compounds also occur in interstellar clouds, which are birthplaces of planetary systems. A planet or planetary satellite is habitable if it sustains life that originates there or if it sustains life that is carried to it.
