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 topicThese images of Mars' asteroid-sized satellites Phobos (right) and Deimos (left) were taken by the Viking Orbiter 2 and 1 respectively. Phobos has a mean radius of approximately 11 km and Deimos 6 km. Phobos is a little more than 9000 km from Mars, while Deimos is more than 23 000 km away from the planet. Both satellites are believed to be captured asteroids composed of carbon-rich rock and both are heavily cratered from impacts of meteoritic debris. Photo: NASA