Two International Space Station crewmen will embark on a spacewalk Monday, their first since they took up their duties on the outpost one month ago. The outing gives them the chance to carry out some maintenance chores.
U.S. Station commander Bill McArthur and Russian flight engineer Valery Tokarev will leave the station unattended inside, as they float out of the U.S. module attached to tethers.
The U.S. and Russian space agencies prefer a third crewmember to remain inside to help the spacewalkers in and out of their bulky spacesuits and oversee their outside activities. But there has not been a third person aboard the station since the moratorium on shuttle flights after the Columbia disaster in 2003. This is because Russian cargo craft are not large enough to carry enough supplies for a trio.
So, flight controllers on Earth will run the station during their spacewalk, or, as mission directors call it, an EVA for extra-vehicular activity. The lead U.S. flight controller is Sally Davis.
"This is not the first EVA that we've been a part of without anyone inside. We've actually done several of them out of the Russian segment," said the lead U.S. flight controller Sally Davis. "It is the first time we've done a U.S. EVA without anyone inside."
It will be the first time in 2.5 years that spacewalkers have left the U.S. module wearing U.S. space suits. During that time, previous crews had used Russian apparel and floated through the Russian module. The U.S. module's airlock and the American space suits had been contaminated by debris, but the portal has been repaired since then, and new U.S. suits sent up.
During the planned 5.5-hour outing, astronaut McArthur and cosmonaut Tokarev are to install a television camera and lights on the edge of the station that will be used to observe future construction when space shuttles return to flight. That is expected to be in May of next year, or later.
The spacewalkers will also remove an experiment that measured the electrical environment around the outside of the station, as it flies through Earth's magnetic field.
The American official in charge of the spacewalk, Anna Jarvis, says the chores are mundane, but necessary.
"The largest challenge is just getting out the door on time and coming back in. The tasks themselves are not overly challenging. So, overall, the biggest challenge will be just executing the overall EVA day timeline," said Ms. Jarvis.
Crewmen McArthur and Tokarev are the 12th team to inhabit the space station, which passed its fifth anniversary of occupation last week.