I was looking at the Consolidated Appropriations Act, 2008 for NASA and saw this:

That none of the funds under this heading shall be used for any research, development, or demonstration activities related exclusively to the human exploration of Mars.

http://frwebgate.access.gpo.gov/cgi-...d=f:39564b.pdf

The information for NASA starts on page 39 and spells out their appropriations pretty clearly. I guess I thought that NASA was doing some amount of research to get to Mars. I guess I was wrong.