Video: Antares post-launch news conference

An unexpected, quickly-planned spacewalk is on tap Monday to troubleshoot a problem preventing the International Space Station’s robot arm transporter from reaching a worksite where it can be locked down, a requirement before a Russian Progress cargo ship can dock later in the week.

Armed with a knife, scissors and other cutting tools, cosmonauts Oleg Kononenko and Sergey Prokopyev went outside the International Space Station on Dec. 11 to slice into the thermal insulation of a Soyuz spaceship and inspect the site of a repaired air leak that briefly caused a minor drop in air pressure in the research outpost earlier this year.

A solid-fueled rocket motor mounted horizontally on a Utah hillside ignited and powered up to more than 3 million pounds of thrust Tuesday in a final full-up test-firing before a similar booster helps propel NASA’s huge Space Launch System away from Earth on a demonstration flight in 2018.