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The Sun, Moon and Earth's oblateness lead to long-periodic perturbations of the inclination of geostationary satellites. The period is 54 years and the maximum inclination is 15º. Thus, uncontrolled satellites will steadily gain an inclination of 15º after 27 years. They will then cross the geostationary orbit twice a day with a velocity of 3,000 kms/hour with respect to other, controlled geostationary satellites.