Sirio-2 ready for launch

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]