Two Chinese astronauts went on a spacewalk on Saturday from a new space station due to be completed later this year. Cai Xuzhe and Chen Dong installed pumps, a handle to open the hatch door from the outside in an emergency, and a leg to attach an astronaut’s legs to a robotic arm, state media reported. China is building its own space station after being blocked by the US from the International Space Station because its military runs the country’s space program. US officials see a number of strategic challenges from China’s space ambitions, an echo of the US-Soviet rivalry that prompted the moon race in the 1960s. The latest spacewalk was the second during a six-month mission that will oversee the completion of the space station. The first of the two labs, a 23-ton unit, was added to the station in July, and the other is due to be sent later this year. The third crew member, Liu Yang, supported the other two from within during the spacewalk. Liu and Chen performed the first spacewalk about two weeks ago. They will be joined by three more astronauts near the end of their mission, the first time the station will have six people. China became the third country to send a person into space in 2003, after the former Soviet Union and the United States. It has sent rovers to the moon and Mars and brought lunar samples back to Earth.
