National Space Society

The National Space Society (NSS) is a Washington DC-area nonprofit founded in 1974 (through the eventual 1987 merger of the L5 Society and the National Space Institute) that advocates for space exploration, development, and permanent human settlement beyond Earth. The L5 Society was founded by Carolyn and Keith Henson, inspired by physicist Gerard K. O'Neill's vision of large human settlements at Earth-Moon L4/L5 Lagrange points detailed in The High Frontier (1977); the National Space Institute was co-founded by Wernher von Braun.

NSS publishes Ad Astra magazine and hosts the annual International Space Development Conference (ISDC), one of the longest-running space advocacy gatherings in the world. NSS members and alumni have played founding roles in numerous space organizations including the International Space University (ISU). Policy priorities include expanding commercial space, establishing property rights frameworks for space resources, development of space solar power as a clean energy source, and increasing NASA's human spaceflight budget.

NSS chapters operate globally with thousands of members, making it the largest citizen-led space advocacy organization by membership. Its vision: a spacefaring civilization with humanity living and working throughout the solar system.