Satellite Industry Association
Science, Technology, Space, Organizations and Associations - Satellite Industry Association. Contains overview and membership forum of a communications satellite industry trade organization in USA.
https://sia.org/
Space Access Society
Science, Technology, Space, Organizations and Associations - Space Access Society. Newsletters and event listings of an organization that promotes cheaper access to space.
https://www.space-access.org/
National Space Society
Science, Technology, Space, Organizations and Associations - National Space Society. Comprehensive overview with newsletters, member forum and activities of an US association to advance the day when people will live and work in space.
https://www.nss.org/
Australia Chapter
Science, Technology, Space, Organizations and Associations - The Mars Society. Australia Chapter.
https://www.marssociety.org.au/
The Mars Society: Illinois, Chicago North Shore Chapter
Science, Technology, Space, Organizations and Associations - North Shore Mars Society. Welcome to the North Shore Chicago chapter of the Mars Society, whose purpose is to further the goal of the exploration and settlement of Mars.
http://nsms.iwarp.com
The Mars Society
Science, Technology, Space, Organizations and Associations - The Mars Society. Provides a variety of resources related to the exploration of Mars.
https://www.marssociety.org/
NASA Institute for Advanced Concepts -- Home
Science, Technology, Space, Organizations and Associations - NASA Institute for Advanced Concepts. Overview of organization and projects by an association of universities.
http://www.niac.usra.edu/
Spacefleet
Science, Technology, Space, Organizations and Associations - Spacefleet. Offers forum and news by a group of space flight enthusiasts.
http://www.spacefleet.org.uk