Astronaut Tim Peake will today make the first spacewalk by a Briton.
Here are eight things you might not know about going out on a limb in orbit:-
1. A spacewalk is also called an Extra Vehicular Activity (EVA). This stands for any activity an astronaut does while outside of the vehicle in space.
2. Astronauts have to wear spacesuits for a few hours before they go on a walk, in order to breathe in pure oxygen. This allows them to get rid of all the nitrogen in their body, which could form painful gas bubbles inside the body if they walked in space.
3. When on a spacewalk, astronauts tether themselves to the spacecraft so they don’t fly away. They also tether tools and objects that they need to themselves.
4. Astronauts use jet thrusters to move around in space. If they become untethered, these jet thrusters allow them to move back to the spacecraft and not fly away! These are worn as a backpack and controlled with a joystick, like a video game.
5. Russian astronaut Alexi Leonov was the first person to go on a spacewalk in March, 1965 for 10 minutes. These days, spacewalks can be up to 8 hours long.
6. Spacewalks allow astronauts to both test how objects react in space and to fix problems outside the vehicle. Today’s spacewalk will enable Peake and Kopra to change a failed electrical component.
7. To train for a spacewalk, astronauts do activities in a Neutral Buoyancy Laboratory near NASA’s station in Texas. Floating in space is often compared to moving underwater.
8. It is possible to boil your blood while on a spacewalk. In a vacuum like space, without the pressurisation of a spacesuit, your blood would boil as the gas in it expanded. This is why making sure their suit doesn’t tear is important for an astronaut.