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 before – 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.
