NASA decided Sunday not to delay launching the space shuttle Endeavour because of a faulty engine part discovered in a sister craft, but bad weather could still postpone the mission.
After the shuttle Discovery was used in repairing the Hubble Space Telescope in December, it was found to have a turbine seal that should have been discarded as defective.
Engineers spent three days reviewing service records of Endeavour's three main engines before deciding that the risk of a similar mistake was negligible and giving the go-ahead for a launch today.
But the weather forecast did not look good. A cold front that was expected to move across the Florida peninsula had stalled and might reach Cape Canaveral too close to the planned start of Endeavour's earth-mapping mission.
"The closer the front is to us, the better the chance for precipitation and thick clouds," shuttle weather officer Ed Priselac said. The space agency will not launch in rain or hail, and thick clouds can hamper its ability to track a shuttle visually.
Priselac said that there was only a 40 percent chance of good weather for a liftoff today but that by Tuesday the chance of good weather would increase to 80 percent.
Bad weather was also predicted at two of the shuttle's emergency landing strips, in California and New Mexico.
If Endeavour does not launch today or Tuesday, the next available opportunity would come Feb. 9.
On the eve of the 11-day mission, the agency that supplies classified images to U.S. defense and intelligence agencies said there still was no final agreement with NASA on how the highly detailed topographic maps it will produce might be distributed to scientists.
The six-astronaut crew, once in orbit, is to use sophisticated radar equipment to make a classified, high-resolution map. Later, a less detailed version will be generated for the world scientific community.
But for scientists and engineers, the question remains: How do they get access to the best images, the classified stuff, which could be used to improve agriculture, water management and urban planning?
The head of the U.S. National Imagery and Mapping Agency, speaking to reporters, said his agency, in meetings with NASA officials, had not arrived at a protocol that would allow the more detailed map to be distributed on a case-by-case basis. The mapping agency is paying the space agency $200 million for the mission.
"We're still discussing the details of how it will be handled," Air Force Lt. Gen. James C. King said. "(The two agencies) will continue to cooperate on facilitating the scientific access to the data that is currently being withheld."
King said any final agreement would probably exclude commercial use of the digital maps, the most accurate and high-resolution images ever collected on a global scale, but data almost certainly would be released on humanitarian grounds when "the health, welfare and safety of people around the world" were threatened.