America grieves for the families of the seven astronauts killed aboard the space shuttle Columbia, a sombre U.S. President said Saturday.
"These men and women assumed great risk in the service to all humanity," George W. Bush said at a news conference in Washington, D.C.
In an age where space travel has become almost routine, it is easy to overlook the difficulties that astronauts face when travelling by rocket into outer space, he said.
The space shuttle Columbia broke apart in flames over Texas on Saturday, shortly before it was supposed to land in Florida.
Columbia had been expected to land in Florida at 9:16 a.m.
Lloyd Robertson with news of the space shuttle's disappearance (1:22 min)
Ivan Semeniuk of the Discovery Channel (3:37 min)
Former CSA astronaut Major Mike J. McKay (9:42 min)
CTV News: Lloyd Robertson talks with Mark Garneau (8:53 min)
It was the 113th flight in the shuttle program's 22 years and the 28th flight for Columbia, NASA oldest shuttle.
In 42 years of U.S. human space flight, there had never been an accident during the descent to Earth or landing. On Jan. 28, 1986, space shuttle Challenger exploded shortly after liftoff.
"These astronauts knew the dangers, and they faced them willingly, knowing they had a high and noble purpose in life," Mr. Bush said.
To the families of the astronauts, Mr. Bush said: "Our entire nation grieves with you."
The President assured the families that the astronauts will not be forgotten and will always have the respect and gratitude of the nation.
"The cause in which they died will continue. Mankind is led into the darkness beyond our world by the inspiration of discovery and the longing to understand.
"Our journey into space will go on," Mr. Bush said.
Mr. Bush quoted the Prophet Isaiah, then ended his brief statement by saying: "The crew of the shuttle Columbia did not return safety to Earth, yet we can pray that all are safely home."