More than 40 years ago, Soviet astronaut Yuri Gagarin blasted into orbit inside what was described as a tin can on top of a bomb, becoming the first out of the block in the Cold War space race with the United States. China is due on Wednesday to become only the third nation to send a manned vehicle into space, the climax of a program launched by Mao Zedong in the 1950s. China, keen to be a world technology leader, is not limiting its space ambitions to manned flight. It plans to explore the Moon and complete a space station by 2020, before heading for Mars.