Summary

Media caption,

Watch the moment Isaacman steps out into space - from the camera mounted on his helmet

  1. How many people have walked in space?published at 10:39 British Summer Time 12 September

    Richard Gray
    BBC Future

    On 18 March 1965, Russian astronaut Alexei Arkhipovich Leonov steps from the spaceship Voskhod 2 to become the first man to walk in outer spaceImage source, Getty Images
    Image caption,

    On 18 March 1965, Russian astronaut Alexei Arkhipovich Leonov steps from the spaceship Voskhod 2 to become the first man to walk in space

    The privately funded spacewalk by Jared Isaacman and Sarah Gillis will be a new milestone in the history of spaceflight.

    They will join an exclusive club – only around 260 other people have ventured outside a spacecraft with nothing but a spacesuit between them and the vastness of the Universe.

    It takes a cool head, a fair amount of bravery and an acceptance that things can – and do – go wrong.

    You can see some of the most beautiful, and frightening moments, in the history of spacewalks in this story.

  2. Watch live from spacepublished at 10:35 British Summer Time 12 September

    We can now bring you SpaceX's live coverage of their mission - press play below to watch.

    Shortly before the walk, the stream will also have analysis from the BBC's own team of experts.

  3. The view from abovepublished at 10:29 British Summer Time 12 September

    Image of Earth from the Polaris Dawn space missionImage source, SpaceX

    We've been getting some incredible images from the Polaris Dawn mission as it orbits the Earth - and a glimpse of life inside the spacecraft...

    Anna Menon, Scott Poteet and Sarah Gillis in zero-gravityImage source, SpaceX
    Image caption,

    Anna Menon, Scott Poteet and Sarah Gillis earlier

  4. Who is the mission commander, Jared Isaacman?published at 10:25 British Summer Time 12 September

    Polaris Dawn Mission Commander Jared Isaacman conducts a meeting as his flight crew performs fighter jet training to prepare for their scheduled launch aboard SpaceXs Falcon 9 rocket that will launch the Polaris Dawn mission from historic Launch Complex 39A at Kennedy Space Center.Image source, Getty Images

    Jared Isaacman, 41, has bankrolled the Polaris Dawn mission and is also the mission commander.

    In 1999 he founded the payment processing company Shift4 Payments, which according to Forbes handles payments for a third of America's restaurants and hotels.

    Forbes also says he has a net worth of $1.9bn.

    He began taking flying lessons in 2004 and five years later set a world record for circumnavigating the world in a light jet.

    Isaacman also founded Draken International, which owns the world's largest private fleet of military aircraft.

    The cost of this week's mission has not been revealed - but he reportedly spent $200m on a previous SpaceX civilian mission in 2021.

    Isaacman is due to walk into space in around an hour's time - stay here for updates and analysis.

  5. Is this regulated by anyone?published at 10:07 British Summer Time 12 September

    Georgina Rannard
    Science reporter

    This spacewalk is a risky and daring move. SpaceX and the four crew on the Dragon craft are trying something no-one has done in decades - a spacewalk without an air lock.

    The US Federal Aviation Administration has oversight of the Dragon rocket and craft, but once it is in space, it is not regulated.

    The only tests they have to pass are ones set by SpaceX themselves. The crew on board have signed consent forms. Nasa has confirmed that it has no involvement with the Polaris Dawn mission.

    The Dragon capsule has been to space dozens of times before, but the spacesuits are untested and it remains to be seen how the craft will perform when depressurised and exposed to the space vacuum outside.

    But of course government space exploration does not have a perfect safety record.

    In 2003, the Space Shuttle Columbia broke apart while re-entering Earth's atmosphere, killing all seven astronauts on board.

    And in 1986 the entire crew of Space Shuttle Challenger died when the machine broke apart 73 seconds into its flight.

  6. How far above Earth are the astronauts?published at 10:05 British Summer Time 12 September

    SpaceX has been giving regular updates on the Polaris Dawn Mission, since it set off on Tuesday:

    A graphic showing the key distances during the Polaris Dawn mission
  7. One small step... astronauts set for first privately-funded spacewalkpublished at 09:58 British Summer Time 12 September

    Isaacman and GillisImage source, SpaceX

    Welcome to our live coverage of what promises to be a historic day in the history of space exploration.

    On Tuesday, SpaceX's Polaris Dawn mission blasted off from the Kennedy Space Center in Cape Canaveral, Florida.

    Four people are on board: Billionaire businessman Jared Isaacman, retired US Air Force Lt Colonel Scott Poteet, and mission specialists (and SpaceX employees) Sarah Gillis and Anna Menon.

    Today, we're expecting Isaacman and Gillis to carry out the first ever spacewalk by civilians - that is, people who aren't full-time professional astronauts.

    You can watch the action live from space later this morning by clicking Watch live at the top of the page - and there will be text updates, pictures, and clips throughout.