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
Go to topicThe principle of radar science used by MARSIS is based on the detection of radio waves reflected by boundaries between different materials. By analysis of these echoes, it is possible to deduce information about the kind of material causing the reflection, such as estimates of its composition and physical state.
Different materials are characterised by their ‘dielectric constant’, that is the specific way they interact with electromagnetic radiation, such as radio waves. When a radio wave crosses the boundary of different layers of material, an echo is generated and carries a sort of fingerprint from the specific materials. The MARSIS antenna booms here are seen receiving reflected signals. The red dotted line denotes the top of the ionosphere of Mars.