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 Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board ESA's Mars Express will employ ground-penetrating radar to map underground water (if it exists) on Mars.
Low-frequency waves will be directed towards the planet from a 40-metre long antenna which will be unfurled after Mars Express goes into orbit. The radio waves will be reflected from any surface they encounter.
In most cases this will be the surface of Mars, but because low frequencies are used, a significant fraction will travel through the crust to encounter further layers of different material - perhaps even water.
Analysis of the echoes produced will reveal much about the composition of the top five kilometres of the crust.