Earth observation for civilian purposes is a space discipline that very quickly inspired the Europeans. As early as 1977, ESA launched Meteosat 1, the first optical satellite charged with observing our world from a geostationary orbit. Devoted to meteorology, it has been followed by a series of increasingly sharp-eyed successors – we are currently at Meteosat-7 – operating at every possible wavelength, both visible and infrared. This family of satellites are in geostationary orbit at a height of 36 000 kilometres and are thus fixed above an area of the Earth’s surface that they observe continuously.

Spot, Envisat and the others

In 1978 a second series of satellites was launched: the Spot (Satellite Pour l’Observation de la Terre) family, born of cooperation between France, Belgium and Sweden. Five Spot satellites have been launched to date, travelling in lower, circular and heliosynchronous orbits at a height of 830 kilometres. The latest, Spot-5, produces images showing details of 2.5 metres on the ground in black and white (panchromatic) and 10 metres in colour (multispectral).

ESA has also developed and launched a number of scientific satellites, such as the ERS (European Remote Sensing satellite) programme of radar satellites. Two satellites of this family were built under this programme adopted back in 1982, one of which, the ERS-2, is still in orbit today. It has since been joined by the giant Envisat satellite.

However, ESA’s Earth observation resources are not limited to these major programmes alone.

‘Third party’ missions

The European Space Agency also makes its ground facilities available to third countries for the receiving, processing and archiving of images obtained by other Earth observation devices. It was in the framework of one of these third party missions that an ESA experimental satellite, the small Belgian Proba (Project for on-board Autonomy), was launched. Originally positioned in orbit in 2001, this technological demonstration satellite was supposed to remain in space for a year at the most. However, such was its operational performance that this tiny orbital platform (weighing just 100 kilograms) is today still continuing to supply ever more surprising images of our planet, thanks to its high resolution camera and compact British-made multispectral imager.

Targeting the future

Today there can be no denying the attraction of Earth observation. Many projects are in the pipeline, both in Paris, headquarters of the European Space Agency, and in Frascati, on the outskirts of Rome, home of ESRIN, the ESA centre for Earth observation programmes.

This European enthusiasm and the many projects planned for the future are attracting scientists from every continent, including the United States. “Quite simply because Europe has made it a priority, whereas the United States is at present cutting back on its Earth observation budgets,” explains Simonetta Cheli, head of public and institutional relations at ESA-ESRIN, Italy. “More and more US scientists working in this field are seeking to cooperate with European researchers so that they can benefit from the new data obtained by our orbiting instruments.”