We finally have blast off! Four astronauts leave Earth for private spacewalk after weeks of delays due to bad weather

Following a series of delays due to bad weather, the historic Polaris Dawn has finally blasted off to space.

SpaceX's Crew Dragon capsule – carrying four non-professional astronauts – launched from Kennedy Space Center in Florida at 05:25 local time (10:25 BST).

The four-person team will fly up to 870 miles away from Earth atop a Falcon 9 rocket. 

This will be the furthest from Earth that any human has travelled since the Apollo moon missions and will carry the crew into Earth's radioactive Van Allen Belt. 

The five-day mission aims to carry out the first-ever spacewalk by private citizens – so those who don't work for national space agencies such as NASA. 

SpaceX confirmed the successful launch on X (Twitter) with a stunning photo and the caption: 'Liftoff of Polaris Dawn!' 

Polaris Dawn is a 'first-of-its-kind' private astronaut mission to space featuring four US engineers and pilots – Jared Isaacman, Scott Poteet, Sarah Gillis and Anna Menon.

Isaacman is a billionaire entrepreneur and commander of Inspiration4, a private spaceflight using SpaceX's Crew Dragon Resilience in September 2021. 

Mr Isaacman, the founder of the electronic payment company Shift4, bankrolled the mission and selected his personal friend, Mr Poteet, as his mission pilot.

He has declined to say how much he has spent, but it is estimated to be more than $100 million.

Roughly ten minutes after launch the main engine cut off and detached, leaving the Dragon capsule to fly with its secondary booster.

After 20 minutes in flight, commentators on the SpaceX livestream remarked that 'everything looks good' as the crew began to 'float free' in microgravity. 

For Polaris Dawn, Isaacman and his crew will spend up to five days in orbit, flying higher than any Dragon mission to date and also attempting to reach the highest Earth orbit ever flown. 

They will reach peak altitude on the first day of the mission when Polaris Dawn will briefly enter the Van Allen belt, where Earth's magnetic field traps extremely dangerous highly-charged particles. 

Later they will also conduct a spacewalk and support scientific research designed to advance 'understanding of human health during future long-duration spaceflights'.

This will be the first human spacewalk conducted by astronauts not associated with any national space agency. 

In a post on X, SpaceX said: 'Dragon will initiate a two-day pre-breathe process to prepare the crew for their upcoming spacewalk on Thursday, September 12'. 

Moving from inside the pressurised capsule to the vacuum of space can cause any dissolved gasses in the bloodstream to expand into bubbles.

Just like a diver coming up from depth, there is a risk that astronauts can develop decompression sickness during this transition. 

To avoid this, the Polaris Dawn crew will spend the next two days breathing an oxygen-rich gas mixture to purge their bodies of nitrogen. 

This is considerably longer than the two-hour pre-breathe usually considered effective for astronauts embarking on spacewalks from the International Space Station (ISS). 

Once prepared, Mr Isaacman and the crew will don their newly designed SpaceX Extra Vehicular Activity (EVA) suits.

These spacesuits come complete with heads-up displays, helmet cameras, and advanced joint mobility systems. 

At an altitude of 435 miles (700km) above Earth, the crew will take turns to venture out of the spaceship in pairs for their walk while the others remain seated to monitor their crewmates.

Although only two will exit the spacecraft at a time, the Dragon capsule does not have an airlock so the whole capsule will need to be depressurised. 

This will break the record for the most people simultaneously exposed to the vacuum of space. 

To prepare for this moment the crew have undergone more than two years of training, logging hundreds of hours on simulators as well as skydiving, centrifuge training and scuba diving.

The Polaris Dawn crew will also take the opportunity to test SpaceX's latest laser-based communication system.

They will attempt to communicate between the spaceship and Starlink - SpaceX's more than 6,000-strong constellation of internet satellites, in a bid to boost space communication speeds.

While in space, Polaris Dawn will also conduct nearly 40 scientific experiments.

These include tests with contact lenses embedded with microelectronics to continuously monitor changes in eye pressure and shape.

After six days in space, the mission will conclude with a splashdown off the coast of Florida. 

However, a series of delays has pushed the mission well back beyond its initial scheduled launch in late August. 

On August 28, SpaceX announced that it would abandon its scheduled launch window due to bad weather over the intended splashdown site.

In a post on X, Mr Isaacman wrote: 'Our launch criteria are heavily constrained by forecasted splashdown weather conditions.

'With no ISS rendezvous and limited life support consumables, we must be absolutely sure of reentry weather before launching.'

With risks already extremely high, the company appears to have taken a more cautious approach. 

By that time SpaceX had already delayed the mission's lift-off twice before, once to perform more preflight checkouts and then again due to a helium leak. 

In a post on X at the time, SpaceX CEO Elon Musk wrote: 'We are triple-checking everything to make sure there is nothing more we can do to improve crew safety.' 

However, the mission was nearly grounded once again earlier this month when a Falcon 9 rocket dramatically exploded upon landing.

The reusable rocket boosters are designed to return to Earth, landing under their own thrust on droneships in the Atlantic Ocean.

However, after booster 1062 exploded during a failed landing, the Federal Aviation Authority briefly grounded all further Falcon 9 launches.

This delay not only threatened the Polaris Dawn mission, but also the scheduled recovery of astronauts Butch Wilmore and Suni Wiliams who are currently stranded on the ISS.