Kit Roberts
A flight from SpaceX is set to see the first space walk conducted by a private company.
The very first space walk was achieved on March 18 1965 when Soviet astronaut Aleksey Leonov floated in space for 12 minutes.
Since then, space walks have become a common part of astronauts' trips up into space.
Crew will go on space walks to conduct research or to carry out maintenance on the International Space Station (ISS).
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On February 7 1984 US astronaut Bruce McCandless II became the first person to take a hair-raising space walk without a tether connecting him to the capsule.
A picture shows McCandless II floating out by himself surrounded only by the curvature of the Earth and the inky void of space.
While the crew of the SpaceX ship will be staying firmly tethered to the craft, they will be the first civilians to carry out a space walk.
Previously all space walks have been carried out by people working as part of a government-sponsored programme.
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The SpaceX mission, called 'Polaris Dawn' blasted off today (September 10) with four private citizens on board.
It is setting off on a five-day-long mission which will take the capsule out into high orbit.
In fact, the aim is to take the capsule into the highest orbital altitude reached by humans since the last Apollo mission to the Moon more than 50 years ago in 1972 - a staggering 870 miles above the surface of the Earth.
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The launch had been due to set off in late August, but was pushed back following a helium leak at the launchpad.
It then saw a further setback due to averse weather conditions off the coast of Florida, which is where the capsule would land when it returned to Earth.
Now, however, the mission is finally underway with the four-person crew on board.
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This includes billionaire Jared Isaacman, retired Air Force Lt Col Scott 'Kidd' Poteet, and SpaceX engineers Anna Menon and Sarah Gillis.
Isaacman, who has an estimated net worth of $2 billion, is also funding the mission in partnership with SpaceX.
The billionaire has also previously flown in the first all-civilian mission to orbit in 2021.
He and Gillis will exit the spacecraft on a tether on the third day of the mission.
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However, the craft itself does not have a pressurised airlock, meaning that the entire craft will need to be depressurised for the duration of the walk.
The astronauts will be wearing and testing newly designed space suits for the mission.