The Columbia Accident Investigation Board has received solid data about an "object" seen drifting away from the shuttle the day after launch that, officials believe, may allow investigators to determine the object's size, shape and density as well as whether it was a piece of the shuttle.

The data are part of a growing body of evidence being amassed as the investigation of the Feb. 1 disaster picks up speed, including some "interesting pieces" of wreckage now in a hangar at the Kennedy Space Center in Florida. Among those objects are a landing gear strut and a piece of the left wing that has emerged as an "important piece," an official said.

A senior official of the board, who did not want to be named, said that with the mass of evidence now coming in, he is confident that the board can determine exactly what happened to the shuttle and what actions to take to prevent a recurrence. Investigators may even be able to determine the "initiating event" that led to a breach in the left wing that allowed superheated plasma to enter, causing the wing to disintegrate.

"I would be disappointed if we had to deduce this [the initiating event], but we might," the official said.

During the first week after the crash, NASA officials confirmed that Defense Department radar had seen an object floating away from the shuttle one day after its Jan. 16 launch. At the time, officials said they were reviewing shuttle records to determine if the object could be something as routine as a dump of wastewater or supplies.

There was speculation at the time, however, that the object could be some piece of space junk that hit the shuttle or a piece of the shuttle that was knocked off by a meteoroid.

An official said that investigators now know a lot more about the object, although the analysis continues. Analysts are not yet certain that it was a piece of the shuttle, although the official said that was an "active possibility."

The object was observed on numerous occasions between the time it was first seen Jan. 17 and the time its orbit decayed and it fell into the atmosphere several days later.

The official said analysts believe they can determine the size, shape and density of the object.

A piece of the leading edge of the left wing found early in the search for wreckage has also emerged as an "important piece," the official said. Asked what part of the wing the piece came from, the official said only that "it was not from the outside."

A landing strut also has been found, the official said, but investigators do not yet know if it was from the left or right landing gear. Determining which gear it was from may require testing that will damage the piece, so analysts are going slow in making an assessment, the official said.

The official said the board will have its own experts analyze the importance of insulating foam that broke off the shuttle's auxiliary fuel tank. He said NASA's failure to mention that three pieces of foam, not one, hit the shuttle was reason enough to do an independent analysis. He stressed that he was not accusing NASA of deliberately withholding information.

The official also said he is skeptical of some of the "numbers" that have been reported in the analysis of the foam impact, including the speed at which it hit the wing. The official said the foam, which has received a lot of attention in the news media, remains an important avenue of investigation, but it is only one of many promising areas of inquiry.

"We're not falling in love with any theory," he said.

In Lufkin, Tex., astronaut Dom Gorie, with U.S. Attorney Matthew D. Orwig, left, thanks residents for cooperating in the ongoing search for debris from the shuttle Columbia.