According to the Japan Aerospace Exploration Agency (JAXA), the 5 year old ALOS satellite abruptly lost power on 22nd April 2011. Launched in January 2006, the the design life of the satellite was only 3 years and has performed into it’s firth year as hoped. It’s replacement, ALOS-3, is not expected to be in operation until 2014.
From the JAXA website:
The Japan Aerospace Exploration Agency (JAXA) has been operating the Advanced Land Observing Satellite ‘DAICHI” (ALOS), which has exceeded its design life of three years and its target life of five years. However, at around 7:30 a.m. on April 22, we found that the satellite had shifted its operation mode to the low load mode (*1) and all the onboard observation devices were turned off due to power generation reduction. The anomaly was detected through relayed data via the Data Relay Test Satellite “KODAMA.”
Since then, the power generation has been rapidly deteriorating, and we currently cannot confirm power generation. The DAICHI was launched on January 24, 2006.
JAXA is investigating the cause of this problem while taking necessary measures.
*1: Low generation mode: the mode to save power consumption to maintain the minimum function of the satellite.