Houston: Indian-American astronaut Sunita Williams and her Japanese colleague will again venture outside the International Space Station tomorrow to complete the maintenance tasks they were unsuccessful in during their last outing.

In the wake of the unsuccessful attempt to install a replacement power-switching unit on the truss of the International Space Station, NASA’s Sunita Williams and Japan Aerospace Exploration Agency Engineer Akihiko Hoshide, will venture outside for a second time in six days to complete the work.

This unexpected spacewalk has been scheduled to take place tomorrow morning. Sunita Williams and Akihiko Hoshide will head out once more after last week’s attempt to fix a faulty power relay by installing a spare went unfinished.

Six days after their first spacewalk, which lasted an incredible 8 hours and 17 minutes, they will leave the space station in order to complete their work on a Main Bus Switching Unit (MBSU).

This spacewalk will be the 165th in support of space station assembly and maintenance, the sixth in Sunita Williams’ career and the second for Akihiko Hoshide.

Sunita Williams will wear the spacesuit bearing red stripes.

Akihiko Hoshide will be clad in the spacesuit with no markings.

NASA issued a statement that all international partners of the ISS Mission Management Team were in agreement to try a second spacewalk.

Akihiko Hoshide and Sunita Williams weren’t able to complete their work on August 30th because the bolts would not secure the equipment properly.

NASA has been trying to troubleshoot the problem, and believes it is caused by a misalignment of parts or possible damage to the threads on the bolts.

NASA will conduct a multi-centre news conference following the conclusion of tomorrow’s spacewalk.

The news conference will be broadcast on NASA TV and include space station programme and mission operations representatives.

Prior to the attempted repairs on August 30th, analysis revealed that there was an internal hardware failure on the MBSU, which is used as the station’s primary electrical power routing device.

NASA has stressed however that even before last week’s spacewalk, there was no threat to the health or safety of the ISS crew, the station itself, or the ongoing research.

Researchers say that if they are not able to bolt on a replacement unit, they also have the option of bringing the problem unit inside to try to fix the problem.

NASA Television will provide live coverage of the spacewalk which will begin 7:15 am.