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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1- The core of the USA Technology Package is a little cube of gold floating in space whose trajectory must not be affected by any external influence.
SMART-2 satellite acts as a protective shell. A highly sensitive 'inertial sensor' measures the distance between the proof-mass and the satellite.
2- The solar wind and micrometeorite showers, for example, would influence the trajectory of the free-floating cube.
Instead, these phenomena move the 'protective' satellite, but the cube remains unaffected.
3- When the sensor detects changes in the satellite's position the thrusters are activated, to bring the satellite back to its original position.
SMART-2 thrusters control the spacecraft position to a few thousands of a millimetre.
4- The sensor confirms that the satellite is again centred on the free floating cube.