TOKYO--Worldwide studies of climate and oceans took a heavy blow when Japan lost contact with its sensor-laden Advanced Earth Observing Satellite (ADEOS). "It's extremely disappointing," says Akimasa Sumi, a climate modeler who heads the University of Tokyo's Center for Climate System Research. "There's nothing to do except work to minimize the effect on research."
The $1 billion ADEOS, the first of several new Japanese remote-sensing satellites, was launched last August to gather data on greenhouse gases, the ozone layer, and ocean temperatures and winds. In addition to five instruments from Japan, the satellite, nicknamed "Midori" (Green), carried two sensors provided by NASA and one developed by CNES, the French national space research center.
The first sign of trouble, according to the National Space Development Agency of Japan, was a loss of observation data transmission yesterday morning. Other data indicated the satellite was slightly out of its planned position and unable to draw power from its solar-cell panel. Later in the day, all contact was lost. Officials initially thought the solar panel had been hit by space junk, but later realized ADEOS had been losing solar power for several days. That raises the possibility of an internal failure, says Arlin Krueger of NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Yasuhiro Sasano, an atmospheric physicist at Japan's National Institute for Environmental Studies and project leader for Japan's ADEOS ozone monitoring, says the loss of its sensor is particularly painful because it was the only instrument providing detailed vertical data on the condition of the ozone layer in both polar regions. He notes, however, that the team has 8 months of data and is developing a second-generation ozone monitor for ADEOS II, set for launch in 1999. "It's not like we'll have nothing to do for 2 years," he says. In addition, Krueger, principal investigator for a U.S. sensor that mapped ozone worldwide, says NASA expects to change the orbit of one of its ozone-mapping satellites so it can "take over the role of global [ozone] monitoring."