wo or three days after the space shuttle Columbia's liftoff, a group of NASA engineers asked the shuttle program manager to request the aid of United States spy satellites in determining the extent of debris damage to the shuttle's left wing, but the manager declined to do so, a senior NASA official said yesterday.

Advertisement

The official said the satellites would "absolutely" have helped the engineers measure any damage to the wing's protective heat tiles from debris slamming into them about 81 seconds after liftoff on Jan. 16.

He said Lambert Austin, an engineer at Johnson Space Center in Houston, had asked Ron D. Dittemore, the shuttle program manager, in a group meeting to obtain satellite images to help gauge the damage. Mr. Dittemore turned down the request, even though Mr. Austin was also speaking for several other engineers, the official said.

Mr. Austin and his colleagues were disappointed, the official said, especially because they believed Mr. Dittemore did not have the technical knowledge of imagery to determine whether the images would have been helpful.

Mr. Austin declined yesterday to comment.

Mr. Dittemore also would not comment, but a NASA spokesman said yesterday that Mr. Dittemore and other officials had decided that satellite images would not necessarily help determine damage.

It is unclear how Mr. Austin's request was related to another NASA request for imagery made around the same time to Defense Department officials, and later withdrawn via an e-mail message, which NASA publicly released last month.

The senior official also said some NASA engineers were now questioning whether the debris actually came from the large external fuel tank. The engineers are scrutinizing the solid rocket boosters to see whether the debris could have originated there, he said.

While the shuttle was in orbit, five Boeing engineers concluded in a report to NASA that the debris impact had not caused serious damage based on the assumption, now perhaps faulty, that the debris was a chunk of foam insulation from the external tank.

A central question in the investigation of the Columbia's break-up on Feb. 1 is whether the National Aeronautics and Space Agency and its contractors had enough information to accurately assess the tile damage. Many experts say damage from the debris may have weakened the wing and is the most obvious possible root cause of the accident, though there are many suspects.

A reconnaissance satellite could have been used to capture images of the tiles. Shortly after the Columbia accident, when aerospace experts outside NASA asked why the agency had not sought satellite assistance, Mr. Dittemore said such images might not have been sharp enough.

But the senior NASA official, who agreed to talk on the condition that his name not be used, said: "When a group of engineers puts forward a request, they're not doing it for grins and giggles. Within their minds, they thought that was a path that would resolve some final concerns. I don't know if it was a cost issue, a timing issue. I don't know if assets could not be arranged."

The official added, "If they had done that, we might know something."

It is unclear whether even a better determination of the tile damage would have helped NASA bring the astronauts home safely.

James Hartsfield, a NASA spokesman, said yesterday that there were discussions in the days after liftoff on whether to obtain satellite imagery. Officials decided not to, he said, because they were satisfied with the Boeing analysis and, as Mr. Dittemore indicated, they questioned the usefulness of the images that satellites would provide.

Mr. Hartsfield said someone at NASA did make an early request for imagery to the Defense Department. But he said that request, which "was not coordinated with the rest of the flight operations world," was withdrawn by another NASA official, Roger D. Simpson.

Mr. Hartsfield said he did not know who had made the request to the Defense Department. The National Reconnaissance Office, the government's main operator of spy satellites, is chartered under the Defense Department. The senior NASA official familiar with Mr. Austin's request said that as far as he knew, Mr. Austin did not contact a department official directly and dropped his request after Mr. Dittemore denied it.