Platform
EnMAP SATELLITE The EnMAP satellite comprises a platform - the satellite bus - for accurate, high resolution Earth observation purposes and provides a very suitable and cost effective solution for the EnMAP mission. Its key advantages are the modular and flexible configuration, a highly accurate attitude control concept and a high rate payload data processing chain including broad storage and downlink capacity.
The EnMAP payload, the Hyper Spectral Imager (HSI), is accommodated on top of the spacecraft bus on a most separated intent to account for the demanding stability and thermal requirements of the optical system. Furthermore, this accommodation enables a maximum independency for easy assembly of both, the payload and the bus subsystems.
The satellite dimensions are compatible with the fairing of the PSLV (Polar Satellite Launch Vehicle) launcher, which is able to lift the satellite into the required orbit. Alternative launchers are VEGA, DNEPR and EUROCKOT.
EnMAP Satellite Design Features
| Mass at launch fuel budget | 810 kg (incl. 80 kg margin) |
| Satellite Dimension Structure | 46 kg hydrazine 1.50 m X 1.80 mX 3.00 m Al-sandwich panel concept with internal shear frame |
| Operational lifetime | 5 years |
| Post Operational lifetime | 25 years after lowering the perigee to 500 km |
| Pointing accuracy | 500m nadir |
| Pointing knowledge | 100m nadir |
| Pointing stability | 1.5m/4ms (bus only 0.3/4ms) |
| Pointimg agility | 5 min for +30° (incl. high accuracy pointing stabilization) |
| Power System | 31V nominal solar panels (4.6 sqm) 800 W (EOL) battery supply: Li-Ion cells, 2 modules 132 Ah |
| Attitude control system ACS | 3-axis stabilised sensors: startracker, sun-sensor, magnetometer, gyroscope navigation: GPS actuators: reaction wheels, magnetique torquers< |
| Orbit control system OCS | hydrazine blow-down system thrust: 2 thrusters with 1 N each propellant capacity: 46 kg hydrazine |
