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 footprint of the radar beam on the ground has parts slightly ahead of the satellite and parts behind it. The satellite moves at high speed in its orbit - towards some parets of the footprint and way from others. This relative speed induces slight frequency shifts in the returning radar energy, due to the Doppler effect, shown as blue or red tint here. The radar echo contains the combination of all this energy but by processing a correlated burst of radar pulses it is possible to slice up the returing echo into a series of Doppler beams.