SPACE CENTER, Houston (AP) _ Even though some NASA engineers were worried, Columbia's top mission manager says no one expressed any foam-strike fears to her during the flight and so she did not seek satellite pictures of the damaged spaceship.

NASA's Linda Ham stood by those decisions Tuesday in her first public appearance since the shuttle shattered in the Texas sky almost six months ago.

With tears in her eyes, Ham said ``we all take some responsibility for this and I certainly feel accountable'' as the leader of Columbia's mission management team. But no one person is to blame for the tragedy, she and other managers noted.

``We were all trying to do the right thing. All along, we were basing our decisions on the best information that we had at the time,'' she said.

``Nobody wanted to do any harm to anyone. Obviously, nobody wants to hurt the crew. These people are our friends. They're our neighbors. We run with them, work out in the gym with them. My husband is an astronaut. I don't believe anyone is at fault for this.''

Ham acknowledged that with 20-20 hindsight, there are things the mission management team and all of NASA could have done better.

She said she did not seek spy satellite pictures of the orbiting spaceship because even though engineers wanted pictures, none of them approached her about it during the 16-day flight and she could not ascertain who was making the request.

She talked to a Kennedy Space Center official who was aware of a possible request for spy satellite imagery and told him: ``I really can't find the source, so I don't think we need to pursue this.''

``It ended that day,'' she said. ``It never came up again. Never. Not in a hallway, not in the mission management team.''

It wasn't until after the accident that she learned some of the engineers who wanted the spy satellite pictures had taken part in her meetings, but never spoke up.

Ham, who has since been removed as shuttle program integration manager, had to stop talking at one point in the news briefing. She struggled to hold back tears and bit her lips, but the tears came anyway and she wiped them away with a borrowed handkerchief.

She and two other top NASA officials at Johnson Space Center met with reporters on Tuesday several hours after NASA released the full transcripts of all five mission management meetings held during Columbia's flight.

During the second meeting, on Jan. 21, five days after Columbia's launch, Ham received a short briefing on the 1 1/2-pound chunk of fuel-tank foam insulation that slammed into Columbia's left wing during liftoff.

``Really, I don't think there is much we can do,'' she told her colleagues. ``It's not really a factor during the flight because there isn't much we can do about it.''

Referring to a foam strike two flights earlier, during Atlantis' launch in October, Ham said at the management team meeting, ``I'm not sure if the area is exactly the same where the foam came from that, but the material properties and density of the foam wouldn't do any damage.''

The independent Columbia Accident Investigation Board has since ascertained that the foam almost certainly created a 6- to 10-inch hole in the vulnerable leading edge of Columbia's left wing, allowing hot gases to enter the spaceship during re-entry on Feb. 1. All seven astronauts on board were killed.

Unknown to the mission management team at the time, it was the largest piece of foam insulation to ever strike a shuttle. The estimated impact speed was more than 500 mph.

The chairman of the investigation board, retired Navy Adm. Harold Gehman Jr., said in May that NASA could have launched Atlantis to rescue the Columbia astronauts if the space agency had known early in the flight about the severity of the wing damage. He has faulted space agency management, right alongside the foam strike.

Phil Engelauf, the mission operations representative on the management team, said he probably would not have notified the crew about the foam impact if reporters had not asked NASA about it. One week into the flight, Mission Control sent up a 16-second video clip of the debris strike ``just so they are armed if they get any questions in the press conferences,'' he told the mission management team on Jan. 24.

Engelauf said he did not want the astronauts worrying about what he and other managers considered ``a non-issue.''

``We just did not believe that there was anything that we could tell the crew that they could do anything with,'' he said. ``At the time, we had no indication or belief that there was anything here that was going to affect the crew, even in the long run.''

___

On the Net:

Columbia Accident Investigation Board: www.caib.us