Bush: Journey to Space Will Continue

After returning to a White House with its flag at half-staff, President Bush said despite the tragic loss of the space shuttle Columbia, which disintegrated as it was returning to Earth on Saturday morning, space exploration will go on.

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"This day has brought terrible news and great sadness to our country, the Columbia has been lost. There are no survivors," Bush said from the White House Cabinet room.

"In the age when space flight has come to seem almost routine, it is easy to overlook the dangers of travel by rocket and the difficulties of navigating the fierce outer atmosphere of Earth. These astronauts knew the dangers and they faced them willingly knowing they had a high and noble purpose in life. Because of their courage and daring and idealism, we will miss them all the more," the president, speaking softly and looking grim, said.

"The cause in which they died will continue. Mankind has led in the darkness beyond our world by the inspiration of discovery and the longing to understand. Our journey to space will go on," Bush promised.

Taking on the role of healer-in-chief, the president then ordered all U.S. flags on official buildings at home and abroad to stand at half-staff until Wednesday. Earlier, he called the families of the astronauts to express his condolences.

Bush did not say anything about the investigation that would begin, but White House officials have said that all resources necessary would be committed to learning the cause of the accident.

An independent board made of Transportation Department, Army and Navy officials was formed to investigate all the evidence, including communications, shuttle sensor readings before break up, data from satellites and the debris on the ground.

Bush came back to Washington from Camp David Saturday shortly after he was informed by White House Chief of Staff Andrew Card of the accident within minutes of the 9:00 a.m. EST loss of contact. Bush then called NASA Director Sean O'Keefe.

Earlier in the day, NASA would not officially confirm the loss of the shuttle astronauts, even as debris from the shuttle began raining down on counties in Texas. However, in what was apparent to everyone, a NASA official said, "It's gone."

• Map: Witness/Debris Sightings

Bush returned to Washington by motorcade from Maryland's Catoctin Mountains. He immediately went to the Situation Room to meet with advisers.

National Security Adviser Condoleezza Rice was at Camp David with the president at the time the news was delivered. Vice President Cheney, chairman of the Joint Chiefs of Staff Gen. Richard Myers, Secretary of State Colin Powell and Secretary of Defense Donald Rumsfeld were also all informed of the tragedy.

Rumsfeld is at the Pentagon meeting with advisers there. Strategic Command and Northern Command have been working closely to monitor the situation. Northern Command was set up after the Sept. 11, 2001 terror attacks to defend the U.S.

The FBI is also participating in the recovery of evidence, although FBI spokeswoman Angela Bell said the role was tangential and the bureau was not called in because of any indication of terrorism.

More than one Bush administration official has said there is no indication that terrorism was behind the loss of the shuttle that was 203,000 feet in the air and traveling at 12,500 miles per hour when it apparently split apart.

"There is no information at this time that this was a terrorist incident," said Gordon Johndroe, spokesman for the Homeland Security Department. "Obviously the investigation is just beginning, but that is the information we have now."

"We are awaiting more information from NASA at this point," spokesman Scott McClellan said.

Sen. Kay Bailey Hutchison, R-Texas, who is chairwoman of the Science, Technology and Space Subcommittee of the Senate Commerce, Science and Transportation Committee, said she will call hearings almost immediately to discuss whether budget cuts had caused sacrifices in safety measures. Hutchison told Fox News that O'Keefe had assured her in earlier briefings that safety was always paramount despite budget struggles.

Upon his return, Bush called Israeli Prime Minister Ariel Sharon to express his condolences at the loss of Col. Ilan Ramon, the first Israeli astronaut in space.

Sharon said in a statement issued from his office that "the state of Israel and its citizens stand at this difficult hour alongside the families of the astronauts, the family of Ilan Ramon, and the American people and government."

Ramon's wife, Rona, and their four small children, who have been living in Texas for the past several years as Ramon prepared for the flight, were at Cape Canaveral for the landing. NASA took the astronauts' families to a secluded place.

Bush also spoke with Mexican President Vicente Fox, French President Jacques Chirac, Canadian Prime Minister Jean Chretien and Russian President Vladimir Putin. Bush and Putin have previously expressed their commitment to space exploration. Two Americans and one Russian are currently residing in the International Space Station.

Earlier intelligence on a previously scheduled Columbia flight that was to carry the same crew had raised some concerns but was considered not credible, said a senior law enforcement official, also speaking on condition of anonymity.

The intelligence, however, related to Ramon and not the flight itself. Columbia had been postponed for reasons other than terrorism concerns.

The vice president was hunting in Texas on Saturday morning, but was not in the east Texas area where debris has been falling from the sky, spokeswoman Jennifer Millerwise said. Debris has already been found in three counties.

Homeland Security Secretary Tom Ridge has been calling officials in Texas, Louisiana, Oklahoma, New Mexico and Arizona from the White House to discuss clean-up matters. He also spoke with Mike Brown, acting undersecretary of emergency preparedness and response for the Homeland Security Department, who will activate the Federal Emergency Management Agency to lead the "search, find and secure" mission.

FEMA, which joins the Homeland Security Department on March 1, is activating an emergency support team in Washington, D.C., and a regional operations center in Denton, Texas. FEMA has 10 regional centers.

Fox News' Andy Schwartz and Catherine Herridge and The Associated Press contributed to this report.