Nasa hopes that the third spacewalk will not be necessary, but if so, it would be the first such mission on 25 December since 1973.
On Feb. 7, 1984, two Challenger space shuttle astronauts, Capt. Bruce McCandless II and Col.l Robert L. Stewart, performed the first untethered spacewalk during the STS-41B mission.
Three Chinese astronauts have returned to Earth as national heroes after successfully completing the country's first ever spacewalk.
The 2014 Sochi Winter Olympic torch has been blasted into space on a rocket, where cosmonaut Mikhail Tyurin will take the historic flame on its first ever spacewalk.
Two Russian cosmonauts have taken the torch for the Sochi Winter Olympics on its first historic spacewalk, ahead of next year's games in Russia.
Williams and Hoshide will also be performing the first NASA spacewalk in more than a year.
It was worn by Ed White for the first US spacewalk, as captured here by Command Pilot James McDivitt.
He has flown six space shuttle missions, repairing the Hubble Space Telescope and performed the first shuttle spacewalk in 1983.
It was NASA's first spacewalk that taught engineers on the ground the valuable lesson that successful spacewalking requires a unique set of learned skills.
Mr Jing, 46, is making his second spaceflight after participating in the Shenzhou-7 outing in 2008 - the mission that included China's first spacewalk.
