This marks the third complete book I have edited into hypertext for the NASA history website. I would like to thank Steve Garber NASA History Web Curator for the raw materials and opportunity to do this work.

The content of this book is the responsibility of the individual authors. As such, it is not my right to change or edit subject matter.

In the course of editing this book I took occasional liberties with formatting. Where a page ended in a hyphenated word I combined it onto a single page. I also changed several spelling, capitilizatation, and italic errors within the text. Most notably the images on pages 166 and 170 in chapter seven are both identified as NASA photo no. M-278, ASTRO 17. The number for hypertext version of page 166 was corrected to S61-01250. The nice thing about web documents is errors can be corrected after press. If you find such an error, broken link, or missing image within this document contact me at the following addresses and I will fix them.

henryjjjr@ornl.gov
or
electroglyph@yahoo.com

In doing this text I had to make the decision as to create a text document or hypertext document. I decided to duplicate the book as close to the original as possible. Although the book is divided into chapters, I maintained page divisions and numbers. I also kept footnotes at the end of each page instead of the end of the chapter.

John Stack's Report no. 646 is available as a PDF from the NASA CASI server. In fact, there are many source documents available on the web. I could have kept going forever in editing this work and including hyperlinks. For those of you interested in related source documents here are some places to look:

NASA home page http://www.nasa.gov/

History Office http://history.nasa.gov/

NASA Projects Home Page http://www.nasa.gov/projects.html

 NASA Center for Aerospace Information (CASI) Technical Report Server.  http://www.sti.nasa.gov/RECONselect.html
 

Sincerely
 

John Henry