China Manned Space Agency has confirmed that two of its astronauts, Cai Xuzhe and Song Lingdong, onboard the Tiangong space station completed a nine-hour-long spacewalk on Tuesday, breaking NASA's record for the longest spacewalk. The previous record was held by US astronauts James Voss and Susan Helms who conducted a spacewalk in 2001 that lasted 8 hours and 56 minutes.