Question: Where can I find the official version of the speech that President Ronald Reagan gave on the loss of the Space Shuttle Challenger and the official version of the speech that President George W. Bush gave on the loss of the Space Shuttle Columbia?
Answer: The official version of both speeches can be found in Public Papers of the Presidents as follows:
Address to the Nation on the Explosion of the Space Shuttle Challenger, January 28, 1986 - page 94-95 of:
Reagan, Ronald. 1989. Public papers of the Presidents of the United States Ronald Reagan. 1986. Washington: United States Government Printing Office.
Address to the Nation on the Loss of Space Shuttle Columbia, February 1, 2003 - page 119-120 of:
Bush, George W. 2006. Public papers of the presidents of the United States, George W. Bush: 2003. Washington: U.S. G.P.O.
President Bush's speech is also available electronically through the FDSys system at http://www.gpo.gov/fdsys/pkg/PPP-2003-book1/pdf/PPP-2003-book1-doc-pg119.pdf.