SpaceX's Inspiration4 will blast off on September 15
After years of promises, ever-retreating deadlines and seemingly endless streams of computer-generated imagery, space tourism has finally arrived.
Pioneering companies like Virgin Galactic, Blue Origin and SpaceX are on the cusp of turning paying customers into astronauts for the first time, with their founders and the first true space tourists preparing for landmark voyages to the edge of space and beyond.
After decades of development and rocket science, the three leading companies of this emerging industry have arrived at radically different experiences of space travel.
But what are the experiences on offer, how do they differ, and will anyone actually be able to afford it?
Virgin Galactic’s founder, Richard Branson, became the first person to reach space in a rocket built by his own company earlier this month, when he soared to an altitude of 86 kilometres above the Earth.
The maverick British billionaire, who is well known for his adrenaline-seeking stunts, spent a few minutes floating in microgravity with his fellow passengers and looking back at the curvature of the Earth, before the sleek spacecraft glided back down to land on a runway in the New Mexico desert.
The 90-minute flight was a bold endorsement of an experience that Mr Branson hopes will turn Virgin Galactic into a billion-dollar business.
Unlike its rivals, Virgin Galactic’s offering uses a somewhat unusual method to get its customers to space – but one that is not without precedent in the history of space exploration.
Instead of taking off vertically from a landing pad, Virgin Galactic customers in its spacecraft are first carried to an altitude of around 13.7km (45,000 feet) under a larger carrier aircraft.
The rocket-powered craft is then released, and climbs the rest of the way itself.
Former astronauts like Canadian Chris Hadfield have compared the experience to Nasa’s X-15 spaceplane – a hypersonic, rocket-powered plane that set a host of speed and altitude records in the 1960s.
It too was first carried aloft by a larger carrier aircraft, before being launched and igniting its own engine.
Nasa astronaut Neil Armstrong flew several missions in the X-15 before the moon landings, with another pilot, Joseph Walker, reaching an altitude of 108km – a record altitude beaten only by the space shuttle in 1981.
Though Virgin Galactic’s spaceplane, VSS Unity, isn’t quite capable of reaching the same heights as its experimental predecessor, it does cross into space – at least according to the definition used by Nasa and the US Federal Aviation Agency (FAA), which say space begins at 80km.
Virgin Galactic believes the short, sub-orbital flights it plans to offer will appeal to customers who are already familiar with air travel, with Mr Branson himself keen to emphasise the safety and comfort of the takeoff and landing.
It also wants to make the experience relatively affordable, with tickets for upcoming flights reportedly selling for between $200,000 and $250,000.
Though this cost will still be out of the reach of many, it pales in comparison to the price that some private astronauts have already paid to get to space.
Between 2001 and 2009, seven space tourists made eight flights to the International Space Station on board Russian Soyuz spacecraft, at a reported cost of between $20 and $25 million per trip.
Virgin Galactic has reportedly sold more than 600 seats on planned flights, with several Hollywood stars – as well as Mr Musk – said to be in line for future flights.
Jeff Bezos’s Blue Origin will compete directly with Virgin Galactic in the market for sub-orbital flights with its New Shepard rocket.
The company plans to send its first paying customer into space alongside Mr Bezos, his brother Mark and aviation pioneer Wally Funk, in a flight due to take off on July 20.
Unlike Mr Branson’s rocket plane, New Shepard takes off vertically like a conventional rocket.
Named after Mercury astronaut Alan Shepard, who became the first American to travel to space in 1961 and who walked on the moon 10 years later, Blue Origin’s rocket also climbs higher than its rival, crossing the Karman line which says space begins at 100km above the Earth.
At the end of a flight lasting roughly 11 minutes, the six-seater capsule will touch down using parachutes, near to the launchpad.
Mr Bezos hopes the capsule’s large windows, traditional launch and landing, as well as its autonomous operation, will appeal to customers wanting the best space flight experience.
Teal Group space industry analyst Marco Caceres said: “It's kind of like getting on a ride at an amusement park – you just trust that everything has been checked out, is in good working order ... and you just sit back and enjoy the ride.”
Blue Origin was roundly criticised for posting an image comparing its offering with that of its rival in the lead up to the Virgin Galactic flight, sparking a debate over where space actually begins.
But it is clear that Mr Bezos believes it is important that there is no question over whether its customers have been to space or not.
Blue Origin has not yet revealed how much it plans to charge for a seat on future missions, but passengers will reportedly pay around $200,000.
An unknown bidder paid $28 million for a seat on the July 20 flight, only to back out due to scheduling issues.
The company said that instead, 18-year-old Dutch student Oliver Daemen will be its first paying customer, but did not disclose the price of his ticket. A family spokesperson said it would be considerably less than the winning bid.
He could become the youngest person to go to space – breaking a record held by Soviet cosmonaut Gherman Titov, who was 25 when he blasted into orbit in 1961.
With the announcement that 82-year-old Ms Funk will travel on the July 20 mission, Blue Origin is also planning to send up the oldest person ever to go to space, in an effort to show that its experience is safe for everyone.
Until Mr Branson’s flight, Elon Musk’s SpaceX was the only private company that had actually sent humans to space.
It famously beat Boeing – a true titan of the aerospace industry – in a race to deliver US astronauts from American soil to the International Space Station for the first time in 10 years.
While it has never really billed itself as a space tourism company, the company is planning to launch its first commercial flight to the ISS in 2022.
Three would-be astronauts have reportedly paid $55 million each to take part in a 10-day voyage being carried out with Axiom Space – another private company, which plans to build the first commercial space station.
SpaceX is also planning its own all-civilian mission, Inspiration4, which is due to take off on September 15.
The Inspiration4 mission is being funded by American billionaire Jared Isaacman, who will bring three other passengers with him on the journey.
Unlike Virgin Galactic and Blue Origin, however, Inspiration4 will be an orbital flight lasting several days.
The passengers will ride a modified version of the SpaceX Crew Dragon capsule fitted with a large observation dome, flying around the Earth several times before landing again.
The cost of the mission has not been revealed, but each launch of a reusable Falcon 9 rocket is thought to cost around $50 million.
In an even more ambitious plan, SpaceX intends to use its upcoming Starship rocket to send Japanese billionaire Yusaku Maezawa, eight passengers and one or two crew on a voyage around the Moon.
Though not due to take off until at least 2023, seats on the six-day tour to our nearest celestial neighbour are free, with applicants invited to produce videos explaining why they should get to come along for the ride.
More than a million people applied for the seats before applications closed.