Stuck Mobile Transporter Necessitates Unplanned ISS Spacewalk

Two NASA astronauts aboard the International Space Station (ISS) will make an unplanned spacewalk as early as Monday to fix the space station’s mobile transporter, which got stuck on December 16.  It must be moved before the next Russian Progress cargo spacecraft can dock at the ISS, which is scheduled for Wednesday.

Scott Kelly and Tim Kopra will try to repair the mobile transporter, which moves along the outside of the ISS to position the robotic Canadarm2 for various tasks, put it in its correct location and latch it into place.   Ground controllers were attempting to do that, but it got stuck 4 inches from where it began its move.

NASA is targeting Monday for the spacewalk, but will not make a final readiness decision until Sunday.

Russia’s Progress cargo spacecraft is scheduled for launch at 3:44 am Eastern Standard Time (EST) on Monday and docking with the ISS at 5:31 am EST on Wednesday.  NASA and Roscosmos are anxious to get the cargo spacecraft docked before a “beta angle cutout” from December 24 to January 2 when the Sun’s angle relative to the ISS does not provide proper lighting conditions for either spacewalks or dockings.

A time for the spacewalk has not been determined yet, but it will be broadcast on NASA TV when it occurs.

Kelly has been aboard the ISS since March.  He and Russian cosmonaut Mikahil Kornienko are more than half-way through their “year in space” mission.  Kopra just arrived at the iSS three days ago, but he has flown in space before.  This will be Kelly’s third and Kopra’s second spacewalks.