Nasa astronauts are carrying out a spacewalk outside the International Space Station, in order to make a critical fix to its power systems.
The spacewalk comes after Nasa said it was "at a loss" on how to fix a broken bolt outside the ISS.
The fix is needed to install a new 230-pound power system.
Power on the ISS has been reduced by 25% in the wake of the failure, and expedition 32 flight engineers Sunita Williams of Nasa and Akihiko Hoshide of the Japan Aerospace Exploration Agency will be hoping to put it right on Wednesday.
The spacewalk will begin at about 12.15pm UK time, and last for several hours.