Like its predecessor ERS-1 (launched in July 1991 by a Ariane 40 and successfully operational in-orbit at an altitude of some 780 Km), the ERS-2 satellite launched on 21.04.95 by an Ariane 40, is monitoring the Earth day and night under all weather conditions thanks to its powerful sharp-eyed, clouds piercing radars. ERS-2 is moreover carrying an instrument which helps monitor the ozone layer around the Earth.