According to Dr. Edward J. Weiler, Director of the Goddard Space Flight Center, "Exploration without science is tourism". At the American Astronautical Society's 43rd Annual Robert H. Goddard Memorial Symposium it was quite apparent to all that NASA's current Exploration Initiative is tightly coupled to multiple scientific initiatives: exploration will enable new science and science will enable exploration. NASA's Science Mission Directorate plans to develop priority science missions that deliver science that is vital, compelling and urgent. This paper will discuss the theme of the Goddard Memorial Symposium that science plays a key role in exploration. It will summarize the key scientific questions and some of the space and Earth science m...