A $587 million environmental research satellite launched 10 months ago stopped communicating Saturday and is feared dead in space.

The Advanced Earth Observing Satellite 2, nicknamed Midori 2, is a joint mission between the Japanese and U.S. space programs to monitor our planet's health from orbit.

An illustration of Midori 2 in orbit. Credit: JAXA

Mission controllers did not receive Earth observation data from the satellite at 7:28 a.m. Japan Standard Time on Saturday when the craft flew over a ground station, officials with the Japan Aerospace Exploration Agency said.

At 8:49 a.m., engineers checked the operational status of Midori 2 and found it was switched into a safe mode -- a condition in which all observation equipment is automatically turned off to minimize power consumption. This switch into the safing mode occurred due to an unknown anomaly.

Around 8:55 a.m., communications between the satellite and the ground stations became unstable and telemetry was not received, officials said.

A tracking station also failed to establish contact with the satellite during later passes at 9:23 and 11:05 a.m. JST.

"JAXA is currently analyzing already acquired telemetry data. The analysis result of power generation data by the solar array paddle revealed that generated power has decreased from 6kW to 1kW," the Japanese space agency said in a statement.

"JAXA makes our best efforts to have Midori 2 back to its normal operation by continuing to analyze the telemetry data and working on to understand the current condition of the satellite at our domestic and overseas tracking stations.

"For anomaly cause investigation, JAXA formed the 'Midori 2 anomaly investigation team' led by the president of JAXA."

The satellite was launched aboard an H-2A rocket on December 14, 2002. Its mission was to replace the Midori 1 satellite lost in 1997 by a solar array malfunction that left the spacecraft with no power supply.

Midori 2 was expected to last at least three years, using its suite of five scientific payloads for global environmental research. Studies included the distribution of water vapor in the atmosphere, along with ocean winds, sea surface temperatures, and sea ice, monitoring plant life and vegetation in marine areas and keeping tabs on the Earth's ozone layer.

Spaceflight Now writer Stephen Clark contributed to this report.