After months of deliberation, a panel of outside experts has recommended that the National Aeronautics and Space Administration scrap plans to put six huge scientific platforms in space to gather information for studies of global warming.
Instead of flying the huge observatories--equipped with multiple instruments trained on polar ice caps, ocean currents and cloud formations--NASA should use smaller satellites that can provide the critical information more quickly and less expensively, the panel concluded.
The expert panel, headed by Edward A. Frieman of Scripps Institution of Oceanography, recommended the more modest approach to data gathering in a draft report prepared at the request of Vice President Dan Quayle and the National Space Council. A copy of the confidential document was released by the Federation of American Scientists.
As initially planned, the Earth Observation System would be the most expensive science project in NASA's history. With projected outlays of $30 billion, of which $17 billion would be spent by the end of the decade, it would rival the cost of landing astronauts on the moon.
The enormous expenditures associated with EOS have produced "sticker shock" on Capitol Hill, where lawmakers already had taken aim on NASA's plans to place a manned space station in orbit at an estimated cost of $30 billion to $40 billion.
EOS was conceived as a primary source of data to be fed into mathematical models with which scientists hope to one day predict climatic changes associated with global warming, the possible rise in the Earth's temperature caused by an accumulation of "greenhouse gases."
The chief argument for launching the huge orbiting observatories was that the climate models required simultaneous observations of atmospheric phenomena by an array of scientific instruments.
But, in its draft report, the expert panel concluded that the requirement for simultaneous observations could be carried out just as effectively by "packages of sensors" placed aboard smaller satellites orbiting the Earth in clusters.
Both NASA and the National Space Council refused to comment on the recommendations. A NASA spokesman said agency officials have not yet received a copy of the draft report. In recent months, however, Lennard Fisk, the chief of NASA's Office of Space Science and Applications, has indicated that he would approve a shift away from the original EOS concept.
White House sources said the recommendations are likely to get a favorable reception because they hold out the likelihood of getting important data much sooner as well as cheaper. NASA had planned to launch a total of six of the 15-ton observatories, each equipped with more than a dozen instruments, from Vandenberg Air Force Base beginning in 1997.
The EOS plan has been controversial not only because of the huge cost and the time required to develop the platforms and massive information processing systems, but because circumstances now make it impossible for the space shuttle to make service calls as initially contemplated.
Because the platforms would have to fly in polar orbit to provide full coverage of the Earth's surface, they would have had to be launched from Vandenberg. But, in the wake of the 1986 Challenger accident, plans to launch the shuttle from Vandenberg were scrapped, meaning the orbits could not be matched.