Washington, Jan 7 (IANS): NASA has said two of its astronauts - Expedition 50 Commander Shane Kimbrough and Flight Engineer Peggy Whitson have completed the first of two power upgrade spacewalks at 1:55 p.m. EST (12:25 a.m. Saturday India time).

During the six-hour and 32-minute spacewalk, the two NASA astronauts successfully installed three new adapter plates and hooked up electrical connections for three of the six new lithium-ion batteries on the International Space Station, NASA scientists wrote in a blog post.

They also accomplished several get-ahead tasks, including a photo survey of the Alpha Magnetic Spectrometer.

The new lithium-ion batteries and adapter plates replace the nickel-hydrogen batteries currently used on the station to store electrical energy generated by the station's solar arrays.

Robotic work to update the batteries began in January.

This was the first of two spacewalks planned to finalise the installation, NASA said.

Kimbrough and Flight Engineer Thomas Pesquet of ESA (European Space Agency) are scheduled to conduct the second spacewalk on January 13.

Space station crew members have conducted 196 spacewalks in support of assembly and maintenance of the orbiting laboratory.

Spacewalkers have now spent a total of 1,224 hours and 6 minutes working outside the station.