I got this from Bob Sawyer’s Blog (very much worth reading once in a while).
The Rand Corporation is a think tank. They produce high quality analysis on different problems and corporations and governments spend quite a bit of money for these reports. They have made some of their older documents available as downloads.
This PDF file for Habitable Planets for Man is an very good introduction into what it would take for man to survive on another planet or artificial environment. Sawyer claims that this is his main text book for world building. I have gone through about 30 pages so far and I believe him. There is a wealth of very technical information presented with good explanations. If you ever write a story where men will drop down onto a planet then you need this book.
The book is a scan of the original document and there are many minor problems with it, including, what looks like a lost page. It is about 40 or more years out of date on some things. It was written in 1948 and it was updated, but not recently. It is still a very good read. Scan through it now so when you write that space adventure and come up with a question, you will know exactly where to go to find the answer.