The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
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One of Hubble's 'eyes', the Corrective Optics Space Telescope Axial Replacement (COSTAR) being installed on the Hubble Space Telescope. COSTAR is not really a science instrument; it is a corrective optics package that displaced the High Speed Photometer (HSP) during the first servicing mission. COSTAR is designed to optically correct the effects of the primary mirror's aberration on the Faint Object Camera (FOC). All the other instruments, installed since HST's initial deployment, were designed with their own corrective optics.