Tim Peake is due to make the first British spacewalk, carrying out maintenance on the ISS, since Michael Foale (flying under US citizenship) in 1995. He will be working alongside NASA's Tim Kopra to replace some faulty equipment and install cabling and parts elsewhere.

A technically challenging EVA for a few reasons, not least the time limit, but hopefully fairly straightforward - both astronauts have undergone extensive training and as always, safety is the paramount concern.

EVAs are a semi-regular part of life on the ISS (usually between 5 and 10 per year) as parts fail and must be repaired and replaced, and preparatory work is done for expanding the station and adding or moving new components and modules. They usually last for at least 5 hours, sometimes as long as 8.