The EarthCARE satellite

The three-axis stabilised satellite platform was designed to accommodate the four instruments, which need to provide accurately collocated views of Earth, as well as unobstructed views for solar calibration of the passive instruments.

The satellite design meets these challenges by employing a fully customised carbon fibre-based platform with the radar, lidar and startrackers (used for determining the satellite’s attitude) positioned as close together as possible, thereby minimising alignment errors.

The satellite is dominated by the large Cloud Profiling Radar antenna, which is 2.5 m across.

The solar panel is made up of five sections and covers an area of 21 sq m. Its long trailing configuration behind the platform gives the satellite and overall length of over 17 m and, at the satellite’s low orbital altitude, helps minimise atmospheric drag.

EarthCARE orbits Earth at an altitude of around 393 km. The altitude needs to be as low as possible to optimise the use of the lidar and radar, but not too low where atmospheric drag would impact fuel consumption and the life of the mission.

Since global coverage is required, EarthCARE’s orbit is near-polar. It crosses the equator in the early afternoon, providing optimal illumination and minimal sun glint for the passive instruments.

With two active instruments on board, the radar and the lidar, the system’s power demand is significant. The average power consumption of the satellite is around 1500 W.

The satellite weighs 2200 kg including fuel.

EarthCARE is a joint venture between ESA and JAXA, the Japan Aerospace Exploration Agency.

The EarthCARE satellite was designed and built by a consortium of more than 75 companies under Airbus as the prime contractor.