Chinese astronauts conduct record-breaking 9-hour spacewalk outside Tiangong space station (video)
Cai Xuzhe and Song Lingdong, part of China's three-person Shenzhou 19 mission, spent more than nine hours spacewalking outside the Tiangong space station from late Monday night (Dec. 16) through Tuesday morning (Dec. 17), according to officials with China's Manned Space Engineering Office (CMSEO).