Including the non-governmental organisation of experts committed to expanding the frontiers of space, what were the other two societies Loeb was elected fellow of?
Avi Loeb:  Loeb is an elected fellow of the American Academy of Arts and Sciences, the American Physical Society, and the International Academy of Astronautics, as well as Vice Chair of the Board on Physics and Astronomy of the National Academies. International Academy of Astronautics: The International Academy of Astronautics (IAA) is a non-governmental organisation of experts committed to expanding the frontiers of space.
American Academy of Arts and Sciences, the American Physical Society