ADEOS-2, one of the world's biggest earth observation satellites, has lost contact with the earth since last Saturday due to a possible glitch in its electrical system, a spokesman for the Japan Aerospace Exploration Agency said.

The communications satellite Kodama has stopped relaying data after its sensor developed trouble early Wednesday after the massive flare, Junichi Moriuma added.

ADEOS-2, known as Kodama-2 in Japanese, is "in a serious situation as it may never be switched on again," Moriuma said. "We are trying to determine whether the problem has been a simple hitch or something caused by a flare."

"Even before the massive flare on Tuesday, there have been activities which are also presumed to be flares in smaller scale," he said.

ADEOS, an acronym for advanced earth observation satellite, was launched last December by Japan's state-of-the-art H-2A rocket along with three other satellites including the Australian FedSat which is geared to conduct various experiments.

The spokesman said that abnormal signals were detected on Wednesday in Kodama's sensor which allows it to keep its position in relation to the earth.

Reacting to the signals, the satellite's computer automatically shifted into a safe mode with Kodama's solar panel oriented to the sun to draw power, not to the earth as in its normal mode, he said.

"The problem is presumed to have resulted from the massive solar flare," he said.

Kodama was put into orbit in September last year, moving into a geo-stationary position over the Indian Ocean.

SPACE.WIRE