This optical device operates in the infrared and is used as a target by ground-based laser ranging stations to determine the precise altitude of the spacecraft. Shortly after the launch of ERS-2 in 1995 ESA decided to link the two spacecraft in the first ever tandem mission which lasted for nine months. During this time the increased frequency and level of data available to scientists offered a unique opportunity to observe changes over a very short space of time, as both satellites orbited Earth only 24 hours apart. During 1999 the ERS-1 satellite finally ran out of fuel, far exceeding its planned lifetime. ERS-2 is expected to continue operating for several more years.
Environmental problems require global cooperation.
The political and commercial strength of a united European space power is more important today than ever before. ESA provides just that strength. As its satellite data becomes more widely used across the globe, Europe is becoming firmly established as a major player in the commercial and environmental monitoring aspects of the space industry. The ERS satellites and their data have provided many benefits to people in Europe and throughout the world in three key areas. An environmental library Our planet is constantly evolving around us.