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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Long-term studies of ozone and water vapour in the atmosphere of Mars could lead to better understanding of atmospheric chemistry for the Earth. A new analysis of data from ESA's Mars Express mission has revealed that our knowledge of the way these atmospheric gases interact with each other is incomplete.
Ozone is produced on Mars when carbon dioxide molecules are split apart by ultraviolet radiation from the Sun. Ozone can be split apart by hydrogen radicals, which are produced when water vapour is split apart by ultraviolet light.
The fact that Mars’ atmosphere is 95% carbon dioxide suggests that a global ozone signature is to be expected, except where there is water vapour. But, for a given amount of water vapour, Mars Express observes twice as much ozone as predicted by climate models. Perhaps the ozone destruction by hydrogen radicals is less efficient than expected, or ice clouds could absorb the hydrogen radicals before they have time to split apart the ozone.