Fundamentals

Overview of key issues:

http://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/main.html

Regarding the dangers of spaceflight. There are 10s of thousands of reports, books, articles, conference papers, meeting themes etc on the issue of the dangers of space travel. To develop an understanding of this issue area, you can start harvesting key words for your searches by going to:

http://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/dangers/index.html

Natural history

http://www.amnh.org/ology/?channel=astronomy