ROME — Europe’s three identical Swarm satellites designed to study Earth’s magnetic field from low Earth orbit were successfully launched Nov. 22, after a wait of nearly two years, by a German-Russian Rockot vehicle operating from the Plesetsk Cosmodrome in northern Russia.

The three-stage Rockot vehicle, a converted SS-19 ballistic missile, placed the three satellites into a polar orbit at 490 kilometers in altitude some 91 minutes after liftoff following two ignitions of its Breeze-KM upper stage. All three satellites were reported in good health after exchanging signals with Swedish and Norwegian ground antennas.

The three 500-kilogram satellites were spring-released simultaneously from their dispenser in such a way as to move away from one another. Two of the Swarm satellites will operate 150 meters distant from each other in an orbit of 460 kilometers, while the third will be raised to operate at 530 kilometers during the mission’s four-year duration. 

Swarm is part of the Earth observation program of the 20-nation European Space Agency. ESA Director-General Jean-Jacques Dordain said after the launch that given the agency’s history with satellites, the Swarm trio is likely to operate for as long as a decade.

The Swarm launch suffered repeated delays after one failure and an anomaly on two Russian government missions using the Rockot vehicle, which is commercialized internationally by Eurockot Launch Services of Bremen, Germany, a joint venture of Astrium of Europe and the Khrunichev Space Center of Moscow.

Despite being of Russian origin and operated from a Russian spaceport, Rockot,  thanks to Astrium’s ownership stake in Eurockot, is included in ESA’s list of approved rockets for ESA missions, which otherwise are reserved for vehicles operating from Europe’s Guiana Space Center facility in South America.

With two successful inaugural flights under its belt, Europe’s Vega small-satellite launcher is a direct threat to Eurockot, but ESA and the European Commission have agreed to continue alternating between Vega and Rockot for the moment as they launch the Sentinel series of Earth observation satellites.

ESA officials said the Swarm mission is now budgeted at 236 million euros ($319 million), including 26 million euros in additional costs due to managers’ original decision to switch from a Vega to a Rockot launch, and to the costs of maintaining Swarm teams during the 16 months of Rockot-related delays.

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Peter B. de Selding was the Paris Bureau Chief for SpaceNews.