April 8th is the date when a satellite made from a converted Russian-Ukrainian nuclear missile will be sent into space to map the world's ice fields in an effort to better understand global warming. "The satellite was due to fly in late February but was held on the ground while engineers investigated concerns about the operation of its rocket. Cryosat will ride into orbit atop a Dnepr vehicle, a converted Russian-Ukrainian nuclear missile. The satellite is designed to make detailed measurements of the shape and thickness of Arctic and Antarctic ice. Its data will help scientists to assess better how changing polar ice conditions affect ocean circulation patterns, sea level and global climate. The Dnepr will lift off from the Baikonur cosmodrome in Kazakhstan. The Russian authorities overseeing the flight have advised the European Space Agency (Esa) they are ready to proceed with the mission. Earlier worries that the rocket's second-stage steering engines might not have enough margin on their performance have been allayed."