HOUSTON -- Paint primer leaching off the shuttle launch towers may have eaten tiny holes in the leading edge of Columbia's left wing, weakening it enough to break when struck by a chunk of foam during liftoff, accident investigators said Tuesday.
Air Force Maj. Gen. John Barry said pinholes in the quarter-inch-thick protective carbon lining the leading edge of the wing may have allowed air pockets to form in the material. The air could have gnawed away at the carbon, a process called oxidation.
The holes have appeared on all four space shuttles. NASA patched the larger holes, but did not check for underlying air pockets, investigators said.
The accident investigation board is trying to determine what caused Columbia's destruction. Barry and other members have focused on the left wing, which was hit by debris barely a minute after liftoff.
Pinholes were found on Columbia in 1992, after 12 flights, and later appeared on the other shuttles, Barry said. As many as 40 pinholes formed on each carbon panel, quite possibly the result of zinc leaching out of the paint primer on the metal tower that swings around the shuttle and protects it on each of the two seaside launch pads.
At their weekly news conference, the investigators also said they had found additional defects in a spare shuttle fuel tank, including a bonding problem with the insulating foam. In addition, they said the mystery object that floated away from Columbia while it was in orbit was almost certainly a metal support panel from the underside of the wing's leading edge.
SPACE STATION REPLACEMENTS: American and Russian astronauts who performed a spacewalk together three years ago will make a return trip to the international space station this month to replace its current crew, NASA said Tuesday.
Edward Lu, a physicist, and Yuri Malenchenko, a pilot and engineer, will travel aboard the Russian Space Agency's Soyuz capsule for a space station stay of about six months. The Soyuz is scheduled to lift off from Kazakhstan on April 26.
Senator says pension program in danger
WASHINGTON -- The federal agency that pays retirement benefits of workers enrolled in bankrupt plans is spending increasingly more on administration and operations beyond limits set by Congress, prompting one senator's concern that those rising costs are depleting funds needed for pensions.
The skyrocketing expenses at the Pension Benefit Guaranty Corp. are occurring as an increasing number of employer-provided pensions go broke, according to a report by the General Accounting Office.
"The pension trust funds should be protected for the benefit of the millions of retirees that PBGC is, by law, expected to protect," said Sen. John Breaux of Louisiana, the top Democrat on the Senate Special Committee on Aging.
"The trust fund is not for unnecessary or inappropriate administrative operating expenses that have no relation to termination of pension plans," he said.
But PBGC spokesman Randy Clerihue said the GAO study did not find "unnecessary or inappropriate" expenses and made no conclusions about those costs. Also, such costs have increased with the PBGC's obligation to more underfunded pension plans and their beneficiaries.
Diocese files to block records release
LOS ANGELES -- As sexual abuse scandals engulfed the Roman Catholic Church nationwide last year, Cardinal Roger M. Mahony of Los Angeles won praise for his promise to be an advocate for victims and to provide a full and open accounting of what happened here in the country's largest archdiocese of 5-million Catholics.
On Tuesday, advocates and lawyers for people who say they had been abused by priests labeled Mahony a backbiter and a traitor, after the Archdiocese of Los Angeles went to court to avoid turning over internal church documents about priests being investigated for sexual abuse.
At a hearing in Los Angeles County Superior Court, lawyers for the archdiocese said it has a constitutional right to hold onto church documents, which they said contained privileged information exchanged by Mahony and priests accused of sexual assault. Confidentiality between a bishop and a priest is a central tenet of Catholicism and if violated would infringe on the church's First Amendment right to free practice of religion, the lawyers argued.
William Hodgman, head deputy for the sex crimes division of the Los Angeles County district attorney's office, said the archdiocese's effort was a "stalling tactic that although disappointing was not entirely unanticipated."
He said he believed the court would reject the archdiocese's argument, citing unsuccessful efforts to block the release of files by other archdioceses.
FUNDRAISING REPORTS: North Carolina Sen. John Edwards said Tuesday his campaign for the Democratic presidential nomination raised at least $7.4-million in the first three months of this year. Former Vermont Gov. Howard Dean has said he expected to raise at least $1.5-million from January through March. Massachusetts Sen. John Kerry and Missouri Rep. Dick Gephardt were expected to exceed $4-million each in the first quarter.
POST OFFICE UPBEAT: The Postal Service finished the first half of its fiscal year -- its highest revenue period -- $1.65-billion in the black, the agency reported Tuesday. For the fiscal year that started in September, revenue is $32.8-billion and expenses are $31.1-billion.