JFK's Second State of the Union Speech May 25, 1961

"..this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth."-http://www.luminet.net/~tgort/moon.htm
Audio

"We propose additional funds for other engine development and for unmanned explorations"

"Secondly, an additional 23 million dollars, together with 7 million dollars already available, will accelerate development of the Rover nuclear rocket. This gives promise of some day providing a means for even more exciting and ambitious exploration of space, perhaps beyond the Moon, perhaps to the very end of the solar system itself."

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This set the spending priorities for the decade, huge funding for Saturn (ISP 3-400), medium for Rover(ISP 800), small for Orion(ISP 4-12,000).