Two space station astronauts are making a spacewalk to complete a job left undone last month.
Russians Oleg Kotov and Sergey Ryazanskiy have ventured outside the International Space Station to install a pair of commercially provided cameras.
The men hooked up the Earth-observing cameras during a spacewalk after Christmas, but ground controllers received no data from the cameras and the spacewalkers had to take everything back inside.
The problem was traced to indoor cabling and fixed.
Images from the new cameras will be distributed by the Canadian company that owns them, UrtheCast Corp.
The cameras were launched to the space station in November in a deal between UrtheCast and the Russian Space Agency. UrtheCast will post video on its website and sell images.
The two men were working so hard that Russian Mission Control outside Moscow urged them to "get your breath".
"We'll force ourselves to rest," one of the spacewalkers replied in Russian.
After reattaching one camera to the outside of the Russian portion of the space station, good electrical connectivity was reported between the instrument and Russian Mission Control.
Nasa spokesman Rob Navias said Russian flight controllers were pleased with the results.
The two spacewalkers are now tackling the second camera.
The four other space station astronauts - two Americans, one Japanese and another Russian - are monitoring the spacewalk from inside the space station