After a month of delays, the US space shuttle Discovery has successfully blasted off on a two-week mission.It left the Kennedy Space Center in Florida, with no sign of the fuel leak that prevented its last launch attempt on Wednesday. Discovery is making important deliveries to the International Space Station, including the last piece of its external, structural backbone. It is also carrying solar panels to provide extra power for the platform. A Japanese astronaut is among the shuttle’s seven-strong crew. He will become the first person from his country to live on the space station.