ESA’s second microsatellite, Proba-2, is under development for a launch early in 2006. Like Proba-1, in orbit since October 2001, Proba-2 will be no larger than a domestic washing machine and will weigh only 100 kilograms. The name Proba comes from the Project for On-board Autonomy. It blazes a trail for space engineering in the future, when spacecraft will make operational decisions for themselves. It also typifies a trend towards small but powerful spacecraft, made feasible by advances in miniaturization.
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http://www.esa.int/esaCP/SEMQ5D0P4HD_FeatureWeek_0.html