Photo: ESA

One of the key spacecraft in Europe’s new multi-billion-euro Earth observation (EO) programme has launched from French Guiana, the reports.

Sentinel-2B carries a large camera to image all land surfaces and coastal waters in visible and infrared light.

It joins an identical spacecraft, Sentinel-2A, already in orbit.

The duo will be flown on the same path but 180 degrees apart so that they can provide a complete map of Earth – clouds permitting – every five days.

The Sentinels constitute the space segment of the European Union’s Copernicus environmental monitoring programme.

A suite of sensors is being lofted over the next few years to gather critical information on the state of the planet and to acquire the data needed to inform and enforce EU policies.

Applications range from urban planning and air-quality monitoring to tracking deforestation and glacier retreat.