Authorities used horses and satellite gear Sunday to search for more scorched pieces of space shuttle Columbia across the Texas and Louisiana countryside, as NASA moved ahead with its investigation and the seven astronauts were mourned at church services around the nation.
The shuttle tore to pieces Saturday 39 miles above Texas, in the last 16 minutes of a 16-day mission, as the spaceship re-entered Earth's atmosphere. The tragedy occurred almost exactly 17 years after the Challenger exploded.
NASA chief Sean O'Keefe announced Sunday that Harold W. Gehman Jr., the retired Navy admiral who helped lead the Pentagon's inquiry into the USS Cole bombing, will head a special government commission investigating the Columbia disaster.
The commission will not emphasize ``any pet theory or other approach'' but will look into every aspect of the doomed flight, O'Keefe said on ``Fox News Sunday.''
At Titusville, Fla., where many Kennedy Space Center workers live, the Rev. David Waller of the First United Methodist Church called the trail of smoke from the disintegrating shuttle a ``glistening tear across the face of the heavens.''
The Rev. Mike Weaver of the All Saints Evangelical Lutheran Church in Columbus, Ohio, said the crew had touched ``the face of God.''
The debris being collected from far-flung areas of Texas and Louisiana is being trucked under high security to Barksdale Air Force Base in Louisiana for analysis. A team of 20 engineering experts from the United Space Alliance, a key contractor for NASA's shuttle program, is being sent to examine the debris.
``We're securing all the debris and assuring that we look at every possible angle of what could have caused this horrible accident,'' O'Keefe said.
Authorities in Nacogdoches County, Texas, used everything from horses and four-wheel-drive vehicles to GPS satellite locator devices to track down shuttle debris. But Sheriff Thomas Kerss said the area ``cannot muster enough manpower'' to guard the hundreds of wreckage sites. At least 125 debris sites had been reported in Sabine County, east of Nacogdoches.
Seventy people went to hospitals in Nacogdoches County because they had touched debris and were worried about toxic shuttle chemicals, said Sue Kennedy, the county's emergency management coordinator.
Authorities said divers might be sent into of the Toledo Bend Reservoir, along the Louisiana-Texas line, where a chunk of debris the size of a compact car was seen splashing down. Sabine County Sheriff Tom Maddox said there was no reason to worry about the water supply.
An immediate focus of the investigation was possible damage to the protective thermal tiles on Columbia's left wing from a flying piece of debris during liftoff on Jan. 16. The space agency said the first indication of trouble Saturday was the loss of temperature sensors in the left wing's hydraulic system.
The day before the disaster, NASA officials said that they suspected the wing was damaged during liftoff, but that there was no reason for concern.
``As we look at that now in hindsight ... we can't discount that there might be a connection,'' shuttle program manager Ron Dittemore said Saturday. ``But we have to caution you and ourselves that we can't rush to judgment on it because there are a lot of things in this business that look like the smoking gun but turn out not even to be close.''
The loss of shuttle commander Rick Husband, Michael Anderson, David Brown, Kalpana Chawla, Laurel Clark, William McCool and Ilan Ramon brought a new round of grief to a nation still in mourning after the terrorist attacks of Sept. 11.
``The same creator who names the stars also knows the names of the seven souls we mourn today,'' President Bush said Saturday.
Authorities said there was no indication of terrorism; the shuttle was out of range of any surface-to-air missile, one senior government official said. Security was extraordinarily tight on this mission because Ramon, Israel's first astronaut, was among the crew members.