Challenger disaster: Ronald Reagan's tribute to crew
27 January 2011 Last updated at 17:16 GMT
President Ronald Reagan was due to give his State of the Union address the night of the Challenger disaster in 1986.
Instead he postponed the speech for a week, and appeared on national television to pay tribute to the crew.
He said they were "pioneers", before ending his address with two lines from the John Magee poem High Flight:
"We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and 'slipped the surly bonds of earth' to 'touch the face of God'."