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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This diagram shows how the two SMART-2 spacecraft increase their distance while at the same time their trajectories - the green lines - are controlled with an accuracy never achieved before.
Three techniques are used:
Position 1: A radio-frequency system - the blue waves - is activated in the first place, providing an accuracy of one centimetre.
Position 2: A laser-based system - in the red cone - refines the measurement.
Position 3: Finally, another even more precise laser - the red straight line - allows the relative positions of the two spacecraft to be 'frozen' with an accuracy of a thousandth of a millimetre (a micron).