West Sussex astronaut Tim Peake is due to walk into history high above the earth today.
The spaceman from Westbourne will walk alongside NASA astronaut Tim Kopra in the mission, which is expected to begin at around 12.55pm and last for six hours.
The astronaut has assisted in a similar walk while onboard the International Space Station - but remained inside the craft. This will be his first time outside - and the first space walk ever by a Briton.
Walks traditionally take place so maintenance can be carried out on spacecraft - and they usually last anywhere between five and eight hours.
In this case, the astronauts will work to repair a power unit outside the Station.
The International Space Station website said: “Expedition 46 flight engineers Tim Kopra of NASA and Tim Peake of ESA will venture outside the space station’s Quest airlock to replace a failed voltage regulator that compromised one of the station’s eight power channels last November.
“The spacewalk is scheduled to begin at 7.55am EST and will be the third in Kopra’s career and the first for Peake, and the 192nd for maintenance of the space station.
“It will be the 35th spacewalk using the US Quest airlock. Additional tasks include deploying cables for the future installation of an International Docking Adapter that will accommodate US commercial crew vehicles, and retrieving a broken light from a truss camera.”
If you want to watch the action, tune into BBC2 from 9pm to watch Stargazing Live, hosted by Dara O’Briain and Professor Brian Cox. An additional programme has been planned, dedicated to the spacewalk.
Tim Peake will spend six months on ISS. His mission began on December 15 last year.