NASA astronaut Sunita Williams and her Japanese colleague, Akihiko Hoshide, will again venture outside the International Space Station today to complete the maintenance tasks they were unsuccessful in during their last outing.

Williams and Hoshide are to install a replacement power-switching unit on the truss of the ISS after last week's attempt to fix a faulty power relay by installing a spare went unfinished.

The current ISS crew also features Russian cosmonauts Gennady Padalka, Yuri Malenchenko and US astronaut Joseph Acaba.

TASS, agencies