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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Sirio-2 ready at the Kourou launch site for encapsulation in the Ariane payload fairing. The despun antenna is covered by a protective cylinder (top). Sirio was to be positioned in geostationary orbit over Africa, to relay meteorological data between centres on that continent using simple receive/transmit stations. The other payload was Laser Synchronisation from Stationary Orbit (Lasso), designed for synchronising high-precision clocks at widely-separated locations at low cost. Lasso consisted of 98 laser reflectors (the panel can be seen here under Sirio's main body), photodetectors for sensing laser pulses, and an ultrastable oscillator/counter to time-tag the pulse arrivals. Different ground stations could thus observe the reflected pulses and use the time-tagging to compare their clocks. Unfortunately, Sirio-2 was lost in the Ariane launch failure of 10 September 1982, along with ESA's Marecs maritime telecommunications satellite. [Image Date: 1982/09] [82.09.004-107]