Two astronauts have put the finishing touches to Japan’s KIBO space lab during their fifth and final spacewalk. Floating 360 kilometres above the Earth, Endeavour astronauts Chris Cassidy and Tom Marshburn fitted the new outdoor experiments platform with television cameras.They also rewired a circuit for the station’s steering system and fixed the thermal covering on a Canadian-built construction robot. Endeavour is due to land back on Earth on Friday. One of the Endeavour astronauts will be left in orbit, taking over from Japanese astronaut Koichi Wakata, who is coming back after four and a half months. He has already reported that the specially-designed self-cleaning underwear he has been testing for two months worked perfectly.