Besides spy satellites, Israel also has a number of communications satellites in orbit.

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Jupiter's nearest rival for having the largest number of known satellites is Saturn, with 30 (of which 13 are irregular).

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Second, to accomplish a growing array of missions without increasing budget outlays, the Department of Defense decided to load up next-generation satellites with an excessive number of performance requirements, making them exceedingly complex.

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When Cluster II passes through these so-called polar cusps, instruments on board each of its satellites will measure the magnetic field, electrical current and number of charged particles within the tetrahedron.

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Despite the increasing number of launches, some large suppliers say that there are almost no orders for new satellites in Asia.

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To get the three satellites into their correct orbits, Vega will have to initiate a number of burns of its Avum fourth-stage.

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This is broadly similar to the 1979-2000 average of 7.04 million sq km observed by modern satellites, and the number used to judge current behaviour in the Arctic.

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