The objective of FUEGO programme is the design and development of a space-based system for the early detection and monitoring of forest fires. The studies carried out lead to a LEO constellation of small satellites as the best solution to fulfil the user requirements. This solution allows the utilisation of small service buses as the ones like INTA MINISAT series, reducing the mission complexity and costs. The system consists on a Walker constellation 12/3/2 at 700 km altitude and 47.5 deg inclination orbit, which optimise parameters such as the revisit time and image resolution. The payload is based in a MIR camera to detect forest fires assisted by a VIS/NIR and TIR cameras to improve the resolution of the fire monitoring and to reject false alarms. The acquisition is made by means of a pushbroom technique, using a steerable mirror to point the sensor beam and pitch manoeuvres to increase the coverage.