Space

Johns Hopkins University - Developer of a range of spacecraft and scientific payloads providing project overviews, scientific and engineering articles.
http://sd-www.jhuapl.edu/

Russian Space Web - News and history of the Russian space program by Anatoly Zak, a journalist.
http://www.russianspaceweb.com/

Usenet space archive - Large collection of google group postings on all aspects of space exploration and development.
http://yarchive.net/space/index.html

European Space Industry Directory - ESID is an ESA database of more than 400 space companies and 1000 products.
http://www.esidirectory.org

Jump from Space. - Features a Russian project to sky-jump from space (over 40km altitude). Includes background of the project initiator, Mogamed Tolboev.
http://www.tolboev.ru/

Heavens Above - Real-time satellite, ISS, and Space Shuttle orbital pass information, maps, and star charts.
http://www.heavens-above.com/

Launchdate - Offers an updated list of coming launches, information about ionizing radiation and related resource links.
http://www.launchdate.com/

Encyclopedia Astronautica - Comprehensive resource providing articles on most space technology subjects and space flight history.
http://www.astronautix.com

Space Travel and Exploration - News, information, and resources about space exploration for the armchair space traveler.
http://www.spacehike.com/

Space and Astronomy Reference Links - Provides a space and astronomy related directory.
http://www.refdesk.com/space.html

Space Projects and Info - Offers a collection of popularized material on space projects and astronomy. Includes forums and merchandising.
http://www.aerospaceguide.net/

NASA Skywatch Sightings Calculator - A Java applet that will calculate when spacecraft will be visible in the night sky over the viewer's own location.
http://spaceflight.nasa.gov/realdata/sightings/