Moscow - Canadian astronaut Chris Hadfield has marked his upcoming departure from the International Space Station by singing a cover version of David Bowie's classic song Space Oddity recorded on the orbiting laboratory.Hadfield, who become a global star during his half-year stint on the ISS with regular and sometimes quirky postings on Twitter, is due to touch down back on Earth early on Tuesday.The video of the moustachioed Canadian spaceman crooning his way through the Bowie track has already become a huge hit on YouTube, with over 200 000 views just hours after it was first posted.The video shows Hadfield singing with an impressively melodious voice as he floats through the station in the zero gravity with a guitar which he also plays with some aplomb."Ground control to Major Tom/ Lock your Soyuz hatch/ And put your helmet on," he sings, looking wistfully out into deep space through one of the portholes of the ISS."With deference to the genius of David Bowie, here's Space Oddity, recorded on Station. A last glimpse of the World," Hadfield wrote on Twitter to introduce the song.ClimaxHadfield's voice and guitar solos were recorded on the station although the backing track was compiled by a team on Earth.The video provides a fitting climax to Hadfield's six-month mission to the ISS which has shown him use social media more effectively than anyone in the history of space travel.Hadfield has won over 800 000 followers on Twitter with spectacular photos and videos from the station and also insights into daily life in orbit.He is due to land back on Earth in Kazakhstan on Tuesday morning at 02:31 GMT aboard a Russian Soyuz-TMA capsule along with Russia's Roman Romanenko and Nasa astronaut Tom Marshburn."We're supposed to be sleeping late to be rested for tonight's Soyuz flight home, but I'm finding it hard to sleep in," Hadfield wrote on one of his regular Twitter updates.Hadfield, who was commander of the station, oversaw a dramatic spacewalk at the weekend performed by Americans Marshburn and Chris Cassidy to halt an ammonia leak.