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," reports Voice of America.