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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The black curve shows the spectral distribution of the Sun above the Earths atmosphere (called Air Mass Zero).
The coloured curves (red, green, blue) show the external quantum efficiencies of a standard triple-junction solar cell of Azur Space GmbH, Heilbronn, Germany.
The external quantum efficiency (simplified) is a physical measure to express which percentage of the incoming light on to a specific solar cell can be translated into electrical power i.e. Numbers of electrons out per photon in.
The bright light blue curve represents the simulated Sun spectral distribution achieved with the sun simulator equipment.