Japan Aerospace Exploration Agency (JAXA)
The Japan Aerospace Exploration Agency (JAXA) has been operating the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) for over nine years (despite a design life of three years) as an onboard device installed in the American earth observation satellite Aqua, after its launch on May 4, 2002. Since the end of August, 2011, however, the continuous increase of relatively large antenna rotation friction was detected twice, thus JAXA has been monitoring the condition. At 3:58 p.m. on October 4, 2011 (Japan Standard Time,) the AMSR-E reached its limit(*1) to maintain the rotation speed necessary for regular observations (40 rotations per minute), and the radiometer automatically halted its observations and rotation.
JAXA will continue to analyze this problem, and take necessary measures to correct the situation. We will also launch the successor to the AMSR-E, the Global Change Observation Mission 1st- Water "SHIZUKU" (GCOM-W1.)
*1) When rotation friction occurs, it is necessary to produce a turning force (torque) to offset the friction in order to maintain the rotation speed. The limit in this context means the maximum value of the torque (4.5 Nm,) which the AMSR-E's motor can produce.
(Reference) AMSR-E achievements
The AMSR-E is a microwave scanning radiometer with the world's highest performance. It can observe global-scale water, including ocean ice, surface temperatures, vapors, precipitation and soil water, regardless of weather conditions or if it is day or night by measuring faint radio waves emitted from the Earth.
(1) Contributing to practical areas