Astronauts to perform urgent spacewalk repair Monday

CAPE CANAVERAL, Fla. -- Two NASA astronauts will perform an unscheduled spacewalk next week to help free a stuck cargo transport rail car outside the International Space Station allowing an arriving cargo ship to dock two days later.

Station commander Scott Kelly and flight engineer Tim Kopra will go outside the orbiting laboratory on Monday to release the Mobile Transporter rail car's brake handle which locked during the car's relocation on Wednesday. The rail car became stuck just four inches from its destined work site as flight controllers remotely moved the vehicle along the station's truss located above the U.S. Destiny Laboratory.

"The ISS Mission Management Team met Friday morning and is targeting Monday for the spacewalk, but will meet again in a readiness review Sunday morning," NASA spokesperson Kelly Humphries said. "Managers could elect to press ahead for Monday, or take an extra day and conduct the spacewalk Tuesday."

Humphries explained the relocation work is in support of Wednesday's arrival of the newly upgraded Russian Progress MS resupply craft set to Monday and later dock to the Pirs docking module at 5:31 a.m. EST. The mobile transporter has to be locked down and electrically connected prior to the arrival of Progress.

"We can get there in relatively short order and do the task, but while we are going out the hatch we are going to look and see if there is anything in that general area we can go and work on," Space Station operations manager Kenny Todd said of the possibility of additional work for the spacewalking duo. "All that said, our primary objective is to go out and get this mobile transporter secured at the site. The direction we've given the (planning) team is to look at those things that are out there in that general area we might be able to do."

The first rail car in space was first used in April 2002 following its delivery by the space shuttle. The transporter can move across the station's 356-foot Integrated Truss at up to one inch per second.

Monday's three hour spacewalk will be the 191st in support of maintenance and repairs to the outpost since construction began in 1998. Humphries noted on Friday it will be Kelly's third spacewalk, all occurring during 2015, and the second for Kopra who arrived aboard the station this week.