Below are links to national policies and legislation that form the basis for public policy.
This is the founding legislation for NASA. It is actually a really interesting read. Whenever an Authorization Act is passed, it is actually an amendment to this original Act.
National Aeronautics and Space Act of 1958
The Obama Administration's Space Policy was signed by the President in 2010. It outlines the civil, commercial, and security space policies of this Administration.
The National Space Policy of the United States of America
Signed by President Obama in 2013, it outlines the main principles and goals for our Nation's space transportation efforts in civil, commercial, and security space...
National Space Transportation Policy of the United States of America
This is the NASA Authorization Act that is currently in force. It outlines the direction for NASA and is an amendment to the original National Aeronautics and Space Act. Congress is working on a 2014 Authorization Act but it has not yet passed.
NASA Authorization Act of 2010
This Act distributed specific amounts of funding to NASA in particular programmatic areas. Congress is working on the 2015 Appropriations Act. If it is not passed by September 30, 2014, a Continuing Resolution will need to be passed to keep NASA funded.