Two private citizens have performed a spacewalk, becoming the only commercially-funded crew to perform the risky manoeuvre.
Billionaire Jared Isaacman and engineer Sarah Gillis stepped out of the SpaceX spacecraft around 15 minutes apart, starting at 11:52BST, wearing specially-designed suits.
“Back at home we all have a lot of work to do, but from here Earth sure looks like a perfect world,” Isaacmen said as he exited the craft.
Before Thursday, only astronauts with government-funded space agencies had done a spacewalk.
Images broadcast live showed the two crew emerge from the white Dragon capsule to float 435 miles (700km) above the blue Earth below.
Jared Isaacman emerged first, wiggling his limbs, hands and feet to test his suit. He returned back inside the hatch, and Sarah Gillis, who works for SpaceX, then climbed out.
Both crew narrated their spacewalk, describing how their suits performed outside of the craft.
Getty ImagesThe walk, originally scheduled for 07:23BST, was postponed early on Thursday.
Anticipation and tension grew as the crew prepared to open the hatch on the craft that has no air lock, or doorway between the vacuum outside and the rest of the spacecraft.
The four crew members spent two days “pre-breathing” to prevent becoming seriously ill from decompression sickness, known as getting “the bends”, as the pressure changed. That involves replacing nitrogen in the blood with oxygen.
The craft was then depressurised to bring it closer to the conditions of the space vacuum outside.
This type of space walk took a “very different approach” to previous walks from, for example, the International Space Station, according to Dr Simeon Barber, research scientist at the Open University.
In recent decades astronauts used an airlock that separates most of a craft from the space vacuum outside – but this SpaceX Dragon capsule was in effect entirely exposed to space outside.
“It’s really exciting and I think it shows again that SpaceX is not afraid to do things in a different way,” he told BBC News.
But it was not without major risks.
Mr Isaacman, who funded the Polaris Dawn mission, was the only member of the four-person crew on the Polaris mission to have previously been to space.
He is commander on the Resilience spacecraft with his close friend Scott ‘Kidd’ Poteet, who is a retired air force pilot, and two SpaceX engineers Anna Menon and Sarah Gillis.
The Dragon capsule the team have flown in launched to space 46 times before, taking 50 crew in total. However, the capsule and the spacesuits are not subject to regulation and were untested in this environment.
SpaceXSpacewalks are one of the most difficult manouevres in space, so the fact that a private company has pulled it off is a milestone in the history of space travel.
This walk at 435 miles (700km) was higher than any previous walk, and used innovative technology in the new extravehicular activity (EVA) astronaut suits.
These are an upgrade from SpaceX’s previous intravehicular activity (IVA) suits.
The EVA suit incorporates a heads-up display in its helmet, which provides information about the suit while it is being used.
Sarah Gillis read out data from her heads-up display during her time outside the Dragon capsule.
SpaceX say the suits are comfortable and flexible enough to be worn during launch and landing, eliminating the need to have separate IVA suits.
Extra nitrogen and oxygen tanks were installed and all four astronauts wore the suits, meaning the mission broke the record for the most people in the vacuum of space at once.
The Resilience spacecraft left Earth on Tuesday on a SpaceX rocket.
The mission said it would travel up to 870 miles (1,400km) up in orbit – further than any human has been in space since Nasa’s Apollo programme ended in the 1970s.
Government space agencies like Nasa want the private sector to transport their astronauts on missions and bring down the cost of space travel.
And entrepreneurs like Isaacman and Elon Musk want to expand private space travel so that more non-professional astronauts can go to space.
This is a major symbolic step forwards, but that day is probably a long way off as the costs remain prohibitively high.