DARMSTADT, Germany โ€”Europeโ€™s CryoSat-2 polar-ice-monitoring Earth observation satellite was successfully launched April 8 aboard a Russian-Ukrainian Dnepr rocket and is expected to undergo a six-month checkout period before starting three years of radar observations this fall.

Operating from Russiaโ€™s Baikonur Cosmodrome in Kazakhstan, the Dnepr silo-launched rocket โ€” a converted SS-18 ballistic missile marketed by Kosmotras of Moscow โ€” placed the 720-kilogram CryoSat-2 satellite into a 720-kilometer near-polar orbit inclined at 92 degrees relative to the equator.

A European Space Agency (ESA) ground tracking station in Malindi, Kenya, confirmed the satelliteโ€™s successful separation from the rocket and initial in-orbit health.

The launch, which came four-and-one-half years after the original CryoSat satellite was destroyed in a launch failure of a Russian Rockot vehicle, followed months of delays related to the availability of Dnepr.

The launch had also been delayed because of a last-minute concern that Dnepr would not be able to carry CryoSat-2 to the intended altitude of 720 kilometers. That issue was resolved when Dnepr designers modified the fuel to the vehicleโ€™s second-stage steering engines to permit the 720-kilometer orbit.

It was not only CryoSat-2โ€™s weight that pushed Dnepr to its performance limit. At 4.6 meters in length, CryoSat-2 required Dneprโ€™s extended fairing, which meant that the rocketโ€™s underground silo was left uncovered leading up to launch.

Taking account of the expense of the first satellite, the CryoSat mission will have cost the 18-member ESA about 254 million euros, or $339.4 million at current exchange rates. That figure includes 145 million euros for CryoSat-1 and 109 million euros needed to build CryoSat-2. The budget also includes three years of in-orbit operations.

Astrium Satellites of Friedrichshafen, Germany, built CryoSat-2 under a contract valued at 75 million euros. While the mission is scheduled to last for three years following the six-month checkout, the satelliteโ€™s fuel, batteries and other consumables are sufficient to last for at least five years, said Eckard Settelmeyer, director of Earth observation at Astrium Satellites.

CryoSat-2 is not an exact duplicate of the original CryoSat. Unlike the first version, CryoSat-2 features a backup Siral radar instrument, to be used in the event of a failure of the primary Siral, or SAR Interferometric Radar Altimeter.

Thales Alenia Space of France and Italy built Siral, which follows on a series of satellite radar altimeters including those flying on the U.S.-French Jason ocean-observing satellites.

ESA Earth Observation Director Volker Liebig said CryoSat-2โ€™s ability to measure, with centimeter-level accuracy, the polar ice caps is of obvious environmental importance given that the caps contain an estimated 77 percent of Earthโ€™s fresh water resources.

Some 10 percent of Earthโ€™s land surface is permanently covered by ice, and one of CryoSat-2โ€™s missions is to furnish data permitting better estimates of global warming and associated rises in sea levels.

But in a presentation made just before the launch, Liebig said that as the Arctic regions become more navigable with the reduction of ice coverage, the regions have a geopolitical interest as well for their suspected reserves of oil and gas.

Peter B. de Selding was the Paris bureau chief for SpaceNews.