Live coverage of the launch of shuttle Discovery. The spacecraft is expected to take off on a mission twice delayed by weather concerns, amid concern over a crack in the insulating foam on an external fuel tank.
Richard Harris, NPR science correspondent
David Kestenbaum, NPR science correspondent
Carl Walz, (Colonel, USAF, Ret.); NASA astronaut, currently assigned to the Exploration Systems Mission Directorate at NASA Headquarters in Washington, D.C.