The Space Frontier Foundation  
   Articles, discussion sites, meetings, and government advocacy dedicated to opening the space frontier as rapidly as possible.
   http://www.space-frontier.org

Space Studies Institute  
   The organization founded by Gerard O'Neill, with detailed information about his space settlement proposals.
   http://www.ssi.org

International Space Settlement Design Competition  
   An annual event in which teams of high school students prepare designs for cities in space.
   http://space.bsdi.com

Island One Society  
   Propulsion systems, business ideas, archives of space meetings and journals, and political advocacy for the space frontier.
   http://www.islandone.org

Artificial Gravity  
   Articles on rotating structures by Ted Hall, with links to dissertation, conference papers, and software.
   http://www0.arch.cuhk.edu.hk/~hall/ag/

Space Colonies  
   Full text of the 1977 CoEvolution book _Space Colonies_, which is now out of print.
   http://lifesci3.arc.nasa.gov/SpaceSettlement/CoEvolutionBook/

Living on Green Islands in Space  
   Information about O'Neill-type orbiting habitats and why we may want to built them.
   http://www.dse.nl/~hkl/e_space.htm

Galleria 2433  
   Ideas for colonizing the moon, Mars, the asteroid belt and the galaxy.
   http://interzone.com/~cheung/Gallery.dir/pg.gallery3.html

URANOS: Club for Expansion of Civilization into Space  
   A group of people, mainly Poles or of Polish origin, who believe that expansion into space is a prerequisite for further development of our civilization. An English version of the site is maintained.
   http://www.uranos.eu.org/uranose.html

Space Settlement Initiative  
   A proposal to grant ownership of land on the moon and Mars to companies that establish settlements and agree to sell passage to anyone willing to pay a fair price.
   http://SpaceSettlement.org

The Interstellar Society  
   Newsletters, discussions and design concepts for interstellar exploration of space offered by a non-profit organization.
   http://www.interstellarsociety.org/

Office of Space Commercialization  
   US Government office - studies on market for space tourism, satellite industry, and other aspects of space development.
   http://www.technology.gov/space/

Space Solar Power at NASA  
   design and development of solar power satellites and solar power systems for use in space.
   http://spacesolarpower.nasa.gov/

Laying the Foundation for Space Solar Power: (2001)  
   National Research Council study of NASA's late 1990's space solar power efforts.
   http://www.nap.edu/books/0309075971/html/

Oregon L5 Society  
   Oregon chapter of the National Space Society; many studies and reports on in-situ resource utilization and related aspects of space development.
   http://www.oregonl5.org/

The Space Settlers' Society  
   contacts and articles on European space advocacy, ramjets, and space tourism.
   http://homepage.ntlworld.com/andy-nimmo/Webpage2a.htm

Space Settlement  
   NASA research office offering introduction to the subject with studies, on-line books, links and a student contest.
   http://lifesci3.arc.nasa.gov/SpaceSettlement/

National Space Society Roadmap for the Settlement of Space  
   List of Milestones and Barriers to Space Settlement
   http://www.nss.org/community/roadmap/

Critical Path Roadmap  
   NASA analysis of critical research and development needs for human exploration and settlement of space.
   http://criticalpath.jsc.nasa.gov/

SpaceArchitect.org  
   official website of an American Institute of Aeronautics and Astronautics subcommittee on aerospace architecture comprising architects and associated professionals who organize conference papers, develop educational tools, collaborate on design projects a
   http://www.spacearchitect.org/

Totipotent.org  
   How and why planet Earth is in position to "give birth" and spread life to the rest of the universe.
   http://www.totipotent.org/

Beanstalk elevator  
   "Virtual beanstalk" amateur design group for a (small scale) space elevator.
   http://members.aol.com/beanstalkr/project/

Notable Nearby Stars  
   Information about nearby star systems out to 65 light years.
   http://solstation.com/stars.htm

Space Elevator Reference  
   Scientific, engineering, economic and policy challenges inherent in constructing the solar systems first space elevator.
   http://www.spaceelevator.com/

NASA Ames - Space Settlement Contests  
   Annual design contest for school-age kids, grades 6-12. Links to winning designs.
   http://www.belmont.k12.ca.us/ralston/programs/itech/SpaceSettlement/Contest/

DaedalusaL4 Guide  
   Detailed design study for a 10,000 person space settlement in Earth orbit, using current technology. 2000 Grand Prize Winner in Space Settlement Design Contest.
   http://www.daedalusal4.utvinternet.co.uk/

Space Solar Power Monitor  
   News, discussion, links to latest information on SSP.
   http://www.wronkiewicz.net/ssp/

The Case for Space  
   Articles and short stories by Robert Weidner, on various roads to space colonization.
   http://www.geocities.com/weidner0304/

The Preparation  
   Links between nanotechnology and space colonization; essays on the transhuman future.
   http://thepreparation.com/

The Space Settlement Institute  
   A non-profit association founded to help promote space colonization; emphasis on property rights law.
   http://www.space-settlement-institute.org

Foundation Future 25  
   Emerging platform for long-term thinking, acting and growth. Supporting space colonization and the development of life and humanity on earth earth, the planets and in the universe.
   http://future25.org

Space Solar Power Workshop  
   Discussion of the energy path for space development.
   http://www.sspi.gatech.edu/

Centripetal Vivarium Space Habitats  
   Advocates, as preferable to lunar colonisation or terraforming, the construction of huge manufactured living spaces that can be spun to create gravitational effects.
   http://www.1point1c.org/tech/colony.jsp