Pollution Satellite Still Grounded

The launch of NASA's Aura satellite was put off again Tuesday because of an unknown problem with the craft's recorder, officials said.

It was the third delay in less than a week for launch of the six-year, $785 million mission, which is to study pollution and the health of Earth's atmosphere.

The launch was pushed back to Wednesday morning to give scientists time to figure out the problem in the solid-state recorder, which will store the scientific information Aura collects and then beam it back to Earth, said Mike Tanner, Aura program executive for the National Aeronautics and Space Administration.

Aura was designed to determine the composition of Earth's atmosphere in unprecedented detail. Carried by a two-stage Boeing Delta II rocket, it was scheduled to be launched into orbit 438 miles above the Earth shortly after 3 a.m. Tuesday EDT.

But 20 minutes before liftoff, a problem was detected that may involve the recorder's random-access memory, which stores data short-term, Tanner said.

"We really believe that we don't have a hardware issue or anything like that," Tanner said. But he said scientists want to be cautious because "we can fix (problems) on the ground but we can't fix them up there."

The Aura campaign has seen four launch dates come and go — June 19, July 10, 11 and Tuesday — because of a combination of technical problems and a records check to make sure suspect components had not been used aboard the spacecraft, reports CBS News Space Consultant Bill Harwood.

The launch was initially set for Saturday. It was delayed a day to check whether a transistor problem on an unrelated mission would affect Aura, and then put back two days more to fix a misalignment in a structure that encloses the satellite and second-stage booster.

The 6,542-pound satellite was built by Great Britain, the United States, the Netherlands and Finland.

Aura is the latest in a series of Earth Observation System satellites designed to monitor the health and behavior of the planet's atmosphere, reports Harwood. Once in polar orbit, Aura's four sophisticated instruments will:

• Determine the amount of ultraviolet radiation reaching Earth from the sun and whether a global halt in production of chlorofluorocarbons, or CFCs, is helping the planet's protective ozone layer recover from earlier damage.
• Measure ozone levels in the lower atmosphere and map the sources and movement of aerosols and chemical pollution.
• Study how Earth's climate is changing by monitoring how water vapor and ozone absorb or reflect solar radiation, affecting global temperature.