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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This plot shows water (H2O) and heavy water (HDO) measured by the Stellar and Solar Occultation in the InfraRed (SOIR) instrument on board
ESA’s Venus Express in the upper atmosphere of Venus.
The data shows measured abundances of water and heavy water at altitudes from 70 to 110 km above the surface of the planet. The figure on the right
shows the ratio of HDO to H2O as a function of altitude. The measured ratio is found to be more than twice the value previously measured in the
lower atmosphere.