Across the Nation NASA declares shuttle safe for launch CAPE CANAVERAL, Fla. - With only hours remaining before liftoff, NASA yesterday declared space shuttle Endeavour's engines safe to fly despite lingering uncertainty over two fuel pump seals. The announcement kept Endeavour on track for a launch this afternoon on an Earth-mapping mission. Thick clouds, however, could still force a delay. Shuttle managers ordered an exhaustive review of seals in Endeavour's fuel turbopumps late last week after a defective seal turned up in one of Discovery's main engines. The bad seal should have been thrown away as a factory reject, but instead was installed in a fuel pump that flew on Discovery six weeks ago. It also flew on Discovery in October 1998 - the flight that returned John Glenn to orbit - and on Endeavour earlier that year. NASA was able to determine, through documents, that 16 of 18 seal segments on Endeavour's fuel pumps are certified and good. The paperwork on the two remaining seals is missing. Even though shuttle managers cannot prove the two seals are certified for flight, shuttle managers concluded yesterday afternoon that Endeavour's engines are safe and voted unanimously to proceed with the launch as planned. Shuttle program manager Ron Dittemore said the likelihood of another defective seal turning up on one of Endeavour's three engines is "very, very, very low." '"It goes back to, how likely is it that you'll have a defect? Very low. And what is your test experience? Overwhelmingly positive," Dittemore said yesterday. "Then you look at your design, and your design is to be very safe. And you look at those, and it's a compelling story." Dittemore said NASA will continue to search for the paperwork detailing the history of the two seals. NASA also will review the paperwork for seals in all its other fuel pumps before clearing any more shuttle engines to fly, he said. The nickel-plated seals, each made of six segments, help direct hot gas into the turbine blades to increase engine performance. If a seal should fail, an engine could shut down during launch and force an emergency landing. Dittemore said the defective seal worked fine, but during the last launch, the nickel plating came loose in one spot and the turbine blades gouged a groove into it. He said the odds that it ended up in an engine, rather than in the garbage, are extremely small. On Saturday, Dittemore said the defective seal had flown on six space shuttle launches. He corrected himself yesterday, saying it flew on three launches and was test-fired three times at Stennis Space Center in Mississippi. Endeavour's radar-mapping mission originally was scheduled for September, but was held up by damaged wiring found throughout the shuttle fleet. Six astronauts from three countries are assigned to the mission, which is expected to generate the most accurate topographic map of Earth. Study names best managed U.S. cities WASHINGTON - With robust finances and well-trained public work forces, Austin, Tex., and Phoenix are the best-managed major American cities, according to a Syracuse University analysis that lists Detroit's ''reasonably good grades'' among the ''biggest surprises.'' The study rated the municipal governments of the nation's 35 largest cities in terms of revenues, assigning grades from A to F on five management criterion: Finances, human resources, capital, information technology and results. Phoenix was the only one with an A or A- in all five categories. Austin finished with an A- average because of a B grade on its use of information technology. Indianapolis, Minneapolis and Virginia Beach, Va., averaged B+. New York, Philadelphia, Honolulu, Milwaukee, San Diego, San Antonio, Seattle and Long Beach, Calif., all had Bs. Patricia Ingraham, director of the Government Performance Project at Syracuse's Maxwell School of Citizenship and Public Affairs said the most-improved cities are those that were in the worst shape five to eight years ago - Detroit, Philadelphia, New York and Washington, D.C. Report: Lower AIDS levels decrease spread SAN FRANCISCO - An encouraging study suggests that people with very low levels of the AIDS virus in their blood are unlikely to spread HIV to others. The new study looked at sexual transmission of HIV in rural Uganda. The doctors followed 415 heterosexual couples in which one partner was infected with HIV and one was not. The study found that the higher the level of HIV in the infected person's blood, the higher the risk of passing on the virus through sex. But, for several reasons, the conditions studied in Africa do not precisely mirror the U.S. AIDS situation. Unprotected sex with an HIV-infected person probably always carries some risk, no matter how low their virus level. Originally on page 1A in the 1-31-2000 issue of the Daily.