Washington, Dec 20 (IANS): Expedition 46 commander Scott Kelly and flight engineer Tim Kopra of NASA are set for a spacewalk outside the International Space Station (ISS) on either Monday or Tuesday.

The pair will move the station's mobile transporter rail car so it can be latched in place ahead of the docking of a Russian cargo re-supply spacecraft on Wednesday, the US space agency said in a statement.

The mobile transporter -- used to position the station's robotic Canadarm2 -- stalled on December 16, just four inches from where it began its move while flight controllers at the NASA's Johnson Space Centre in Houston were attempting to reposition it robotically.

The cause of the stall was still being evaluated.

This will be the 191st spacewalk in support of space station assembly and maintenance, the third in Kelly's career and the second for Kopra, who just arrived at the station.

Kelly, who is nine months into a one-year mission, will be designated extravehicular activity crew member 1 (EV1) wearing the suit bearing the red stripes, and Kopra will be extravehicular activity crew member 2 (EV2) wearing the plain suit.

The Russian supply spacecraft is scheduled to be launched from the Baikonur Cosmodrome in Kazakhstan on Monday.