Search for answers begins

NASA: Evidence hasn't revealed cause of disaster

Youngsters pray at The Baha'i Center of Los Angeles for the astronauts who died aboard Columbia.

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ON CNN TV The Shuttle Tragedy: Watch continuing coverage of the investigation, debris recovery and hometown reactions beginning Monday at 6 a.m. EST. SPECIAL REPORT •  Official accident report (PDF) •  NASA aims higher | Slide Show •  Audio Slide Show: Shuttle lost •  Timeline: Investigation •  Gallery: New safety guidelines •  Gallery: Columbia crew •  Report: Findings, counsel •  Special Report VIDEO The manager of the U.S. shuttle program gives a timeline of events leading up to the loss of space shuttle Columbia (February 2) PLAY VIDEO NASA says it is fully supporting the astronauts on the international space station and will continue to fly missions (February 2) PLAY VIDEO Cindy Garza of KPRC reports on the large amount of debris found around Nacogdoches County, Texas (February 2) PLAY VIDEO TO REPORT DEBRIS NASA urges people not to go near debris from Columbia because it could contain toxic substances. People who find debris are asked to call (281) 483-3388. NASA has also set up a Web site  to collect information that may be helpful in the investigation of the shuttle disaster.

JOHNSON SPACE CENTER, Texas (CNN) -- A massive investigation effort shifted into high gear Sunday night as teams sought clues to unlock the mysteries surrounding the final moments of the space shuttle Columbia.

Federal, state and local officials are working to recover the thousands of pieces of debris spread across Texas and Louisiana, and NASA engineers are poring over mounds of data, trying to understand what happened in the moments before Columbia disintegrated in the skies above Texas on Saturday morning. (More on the investigation)

Remains of some of the astronauts began arriving at Barksdale Air Force Base in Louisiana late Sunday. (Full story) There, they will be examined by pathologists from the Armed Forces Institute, NASA spokeswoman Melissa Motichek told CNN.

Director of flight crew operations Bob Cabana said the remains were being treated with the greatest respect.

"We are honoring our fellow crew mates," Cabana said.

Becoming visibly emotional, Cabana said, "Yesterday was probably the hardest day of my life -- to have to sit down with the families and close friends and tell them that their husbands, wives, moms and dads aren't going to be coming home. If you've never had to do that, I hope you never have to."

An astronaut has been assigned to each of the grieving families "to support them and provide what they need," Cabana said.

He said he had talked to the astronauts aboard the international space station and promised to keep them informed of the investigation.

"They're grieving up there, also," Cabana said. "And they feel a little isolated."

Bush to attend memorial

Meanwhile, the White House said President Bush and first lady Laura Bush will attend a memorial service Tuesday in Houston.

The shuttle crew was remembered during worship services across the country Sunday. (More on memorials)

In Racine, Wisconsin, friends and family members mourned mission specialist Laurel Clark at Olympia Brown Unitarian Universalist Church.

"Laurel was a very intense person who would set goals and would go for them," Clark's brother, Daniel Salton, said Sunday. "And I think that's a great role model for kids today. ... You can do great things for humanity if you just set some small goals and always go for the next thing and set your sights higher." (CNN Access)

In addition to NASA's internal probe, an independent investigation will be led by retired Navy Adm. Harold Gehman, who headed the probe of the attack on the USS Cole in Yemen. (More on Gehman)

The seven astronauts killed in the disaster were Rick Husband, Clark, pilot William McCool, payload commander Michael Anderson, mission specialists David Brown and Kalpana Chawla, and Israel's first astronaut, Ilan Ramon.

Space shuttle flights have been put on hold until NASA can learn what caused the disaster. NASA said the international space station, where two astronauts and a cosmonaut remain, has enough supplies to last the crew until June. An unmanned Russian supply ship was launched to the space station Sunday. (Full story)

Authorities again warned the public not to touch any pieces of the spacecraft because they could be contaminated with toxic residue from the shuttle's fuel system and could be crucial to determining what happened to Columbia. (Debris dangers)

Columbia was lost less than a week after the anniversaries of two other deadly space program disasters -- the 17th anniversary of the explosion of the shuttle Challenger on January 28, 1986, and the 36th anniversary of a launch pad fire that killed three Apollo astronauts on January 27, 1967. (Challenger disaster)

Of the five shuttles that have gone into orbit, three remain in the fleet: Endeavour, Discovery and Atlantis.

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