China’s Tianwen-2 spacecraft has captured its first close-up image of a near-Earth asteroid, revealing that the target is even smaller than anticipated – a factor scientists say will make the sample-return task “far more difficult” than previous Japanese and American missions. The probe captured images about 20km (12.4 miles) from asteroid 2016 HO3 during its approach phase, the China National Space Administration (CNSA) announced on Monday. It was close enough for the spacecraft to begin...