, , , br Nigeria Elections: The Key Issues; Scott Kelly`s One Year Mission in Space br Today on CNN Student News: Find out what issues were on the minds of Nigerians, as voters in Africa's largest democracy went to the polls. Discover how an astronaut on a 340-day mission to the International Space Station will become one of the experiments being conducted. And lend your ears to an invention that aims to extinguish fires with low-frequency sound waves.