The spacewalk will be somewhat different to the type we’ve become used to seeing from International Space Station (ISS), where two astronauts will usually go outside while the rest of the crew stays inside the pressurised station.

    The Dragon capsule has a hatch rather than an airlock. This means that the spacecraft’s whole interior will have to be depressurised and exposed to the vacuum of space when Isaacman and Gillis exit through the hatch to carry out their spacewalk 435 miles (700km) above Earth. All four crew members will therefore be receiving their life support through spacesuits while the EVA is underway.

    The crew are wearing EVA suits designed by SpaceX that will be used for the first time on this flight. These are considerably more streamlined than those used by Nasa astronauts aboard the ISS. The design of the older Nasa suit, called the Extravehicular Mobility Unit, has stayed much the same for more than 40 years.

    However, the bulkiness of Nasa’s suits is in part because they have a life support system incorporated into a backpack. By contrast, during the spacewalk, Isaacman and Gillis will receive life support to their suits through long tubes called umbilicals which are attached to the capsule.

    Ambitious objectives

    The significance of the Polaris Dawn EVA can’t be overstated. Spacewalks have been reserved for government-backed space travellers since Alexei Leonov became the first human to step outside a space capsule on the Soviet Voskhod 2 mission in 1965. The first spacewalk by an all-commercial crew is a key moment in the history of spaceflight.

    The ambitious objectives of this mission, however, do also make it somewhat dangerous. While all the crew members are extremely capable and have been well trained for this mission, there are no professional astronauts aboard to advise. It is also the first spaceflight for three of the four crew members.

    Having said all this, Polaris Dawn is an inspiring endeavour. It’s common these days to hear criticism of spaceflight along the lines of: “instead of going to space, why don’t rich people give away some of their money to those in need on Earth?”

    During Inspiration4, Jared Isaacman’s first spaceflight, aboard a Crew Dragon capsule, the businessman raised more than US$240 million (£181 million) for the St Jude Children’s Research Hospital in Memphis, Tennessee. For this mission, he is planning to replicate that success.

    The Polaris Dawn website allows internet users to donate to the St Jude Children’s Research Hospital, with the goal of improving the detection and treatment of childhood cancer around the globe. The crew members will also conduct several health-related experiments during the mission, with the aim of advancing medical research.

    This is the first of three missions in a privately-funded Polaris Program. As more commercial missions take place, the cost of access to orbit will come down. This will help democratise spaceflight, opening it up to those who are not professional astronauts or super-rich.

    Hopefully, it will also inspire the younger generation to see space not as the final frontier, but as a natural expansion of humans beyond the limits of Earth.

    The mission will use the Dragon spacecraft named Resilience, which is the vehicle flown in 2020 for the first full mission to launch US astronauts from American soil following the retirement of the Nasa space shuttle a decade earlier.

    The connection between the achievements of the past and the amazing results of the present is the most intriguing part of the story here. At least that’s how I see it as a child of the Apollo era, and apparently now, as a member of the Artemis generation.