Now it is President Bush's turn to present to the American people the case to move beyond the Columbia tragedy and hold the lead in aerospace discovery.

Discovery is completing only the second shuttle flight since the Columbia tragedy three years ago.

Our guess is that with NASA on high alert after the Columbia tragedy, the next shuttle flights will be the safest ever.

After the heartbreaking Columbia tragedy, it's easy to question whether our space program justifies its risks.

It will be only the second flight since the Columbia tragedy.

In any event, Mr. Rohrabacher said the Columbia tragedy had thrown some old assumptions out the window.

In light of the Columbia tragedy, NASA and the United States government should consider what an accident involving nuclear materials in space would be like.

The Columbia tragedy is a reminder of how hazardous the exploration of space is.

"In the aftermath of the Columbia tragedy, we saw our nation's space program reinvent itself," the statement said.

That the Columbia tragedy happened less than a year after my testimony was an unfortunate coincidence.