||ERS-2 is the follow-up ESA mission of ERS-1 with a launch on April 21, 1995 from Kourou on an Ariane-4 vehicle. It was in 1989 when ESA decided to continue the ERS program beyond the lifetime of ERS-1. The ERS-2 satellite is essentially a copy of ERS-1, except that it includes a number of enhancements; it is also carrying a new payload instrument to measure the chemical composition of the atmosphere, named GOME (Global Ozone Monitoring Experiment). ERS-2 has a total mass of 2,516 kg at launch (about 200 kg more than ERS-1). The mission design life requirement was extended to 3 years. ERS-2 has also the same mission objectives as ERS-1, plus an atmospheric chemistry mission objective (with GOME).