Carl Sagan's rationale for human spaceflight - Plus he would have been 70 on Nov. 9
Sagan's rationale for human spaceflight
Carl Sagan was not an advocate for human spaceflight for most of his
career, but late in life changed mind. Michael Huang believes that the
reasons Sagan adopted for supporting humans in space may be the most
compelling of all.
http://www.thespacereview.com/article/261/1