Science News Roundup: China eyes asteroid defence system, comet mission; Astronauts arrive at space station aboard and more

Following is a summary of current science news briefs.

China eyes asteroid defence system, comet mission

China will hold discussions on building a defence system against near-Earth asteroids, a senior space agency official said on Saturday, as the country steps up its longer-term space ambitions. Zhang Kejian, head of the China National Space Administration, did not provide further detail in his opening remarks at a ceremony for China's space day in the eastern city of Nanjing.

Astronauts arrive at space station aboard SpaceX Endeavour

A four-astronaut team arrived at the International Space Station on Saturday aboard the SpaceX Crew Dragon capsule Endeavour, NASA said, after becoming the first crew ever to be propelled into orbit by a rocket booster recycled from a previous spaceflight. The Endeavour capsule, also making its second flight, was launched into space on Friday atop a SpaceX Falcon 9 rocket from NASA's Kennedy Space Center in Florida. SpaceX is Elon Musk's commercial rocket company.