The European space agency's dart-shaped GOCE satellite, designed to skim through the extreme upper atmosphere using ion drives to compensate for air drag, has launched successfully from Plesetsk cosmodrome in northern Russia.

GOCE had been scheduled for launch yesterday, but a problem with the doors of the Plesetsk launch tower meant that the tower couldn't open up. This meant the satellite's Rockot launch stack (based on a converted SS-19 ballistic missile) couldn't deploy.

The tower snags were rectified swiftly, but by that time the launch window had closed and the launch was moved back to today. The rescheduled Rockot liftoff at 14.21 UK time today appeared to go without problems. Groundside boffins will be hoping to get in touch with the satellite once it gets into orbit, and that event will be streamed live for those interested here.

GOCE's unique low-orbiting design results from the fact that it needs to be deep within the Earth's gravity field in order to measure it with great precision. The satellite's instruments are intended to make a much more precise map of the Earth's geoid, which will let its surface be surveyed much more precisely. This will give the world's scientists a much better idea of what's happening to sea and ice levels in future. ®

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