External Tank
Links
External Tank Manual
http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/et.html
Features extract from the shuttle reference manual.
Orbit 6 - Space Technology and Fiction
Includes links regarding the proposed usage of ET, and technical papers.
PERUN - Space Shuttle External Tank Used as a Space Station
http://staff.infima.cz/svoboda/perun.htm
Paper written in 1979 deals with the possibility of converting an expended Space Shuttle External Tank into a Space Station.
Re-using today's rockets spent fuel tanks in orbit
http://www.permanent.com/ext-tank.htm
Technical website
Space Island Group Project
http://www.spaceislandgroup.com/
Features a project descriptions for building a space station devoted to tourism and 0-G experiments, based on the tanks of the space shuttle. Regularly updated.
Space Shuttle External Tank Applications
http://www.space-frontier.org/Projects/ExternalTanks/
Overview of possible applications of Space Shuttle External Tank
Studies
http://www.freemars.org/studies/index.html
Studies by L5 Minnesota (MN Space Frontier Society)- Uses for Shuttle External Tank in orbit