AllianceforSpaceDevelopment.org The Alliance for Space Development advocates settlements in space.
AmazingSpace.org The best astronomy site on the Web. If you’re interested in the Hubble or James Webb Telescopes, here is where you’ll find the latest data and images.
ESA.int ESA is the European Space Agency. The site contains the latest news from across the pond.
Lunar.xprize.org Google’s $30 million X Prize spurs innovation in low-cost robotic commercial space exploration. As you might expect from Google, this site is very, very cool, including a documentary series produced by J.J. Abrams of Star Wars and Star Trek fame.
NASA.gov One of the least stuffy government websites, packed with multimedia. This is the place to learn how to participate directly with space, from getting your Scout troop’s experiment onto the International Space Station to visiting the Johnson Space Center.
NSS.org The site of the National Space Society, which advocates human colonization of space.
Planetary.org The site for the Planetary Society, Mars Society, SETI Institute, Commercial Spaceflight Federation, and the Coalition for Deep Space Exploration.
Space.com A great source of information, gathered by a commercial online publisher—news of the latest commercial and government launches, astronomy facts, and even an area where you can shop for a telescope.
SpaceDaily.com The go-to site for space news. While geared toward the true space fan, space works on the brain a lot the way baseball does. Follow the players and the games (or, in this case, missions) for a while, and you will find yourself becoming a true fanatic.
SpaceFoundation.org The Space Foundation leads educational programs and holds an annual symposium of space stakeholders.
SpacePlace.nasa.gov A fun site for kids, with everything space and NASA.
SpaceWeather.com Space weather affects telecommunications on Earth, and it can affect the timing of launches. For you and me, it’s a cool way to see how the Sun is impacting (literally) Earth with its cosmic rays. A typical “weather conditions” announcement reads: “Solar wind speed 492.0 km/sec, three sunspots, none of them threatening.”
SpaceX.com Keep up with Elon Musk’s ventures in space.
Stsci.edu Site of the Space Telescope Science Institute, located within Johns Hopkins University. Get a close look at missions run by this inside player.