Briton Tim Peake and American Tim Kopra have just embarked on a six-and-a-half hour spacewalk.
Although not the first Briton to carry out a spacewalk (the first was Michael Foale in 1995), Tim Peake is the first Briton to do so under the UK banner with Nasa.
They will travel 50m (the same length as an olympic swimming pool) along the outside of the International Space Station hand-over-hand to replace a faulty component on the sequential shunt unit that has compromised a power channel. The failed electrical box regulates power from the solar panels.
Watch Tim’s spacewalk live with this link: