A chart taken from Briefing Charts: NASA Associate Administrator Craig Steidle, Office of Exploration Systems, 3 March 2004.
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2004-03-03
<a rel="nofollow" class="external free" href="http://www.spaceref.com/news/viewsr.html?pid=12052">http://www.spaceref.com/news/viewsr.html?pid=12052</a> (<a rel="nofollow" class="external text" href="https://www.nasa.gov/pdf/56249main_codeT.pdf">PDF file</a>)