Commercial space travel is about to go to a new level — literally — as the first all-private crew prepares to blast off to the International Space Station (ISS).
The Ax-1 mission, which is a collaboration between SpaceX and another company Axiom Space, is due to launch from the Kennedy Space Center in Florida around 1:17am (AEST) tomorrow morning (April 9) at the earliest.
On board the SpaceX Dragon capsule will be a veteran astronaut and three billionaire entrepreneurs from the US, Canada and Israel, who've each paid an estimated $US55 million ($71 million) for the ride.
The all-male crew will spend eight days at the ISS before returning to Earth.
The ISS has previously welcomed a few private visitors. The first was US billionaire Dennis Tito in 2001, the most recent were a Japanese billionaire and his producer. But this is the first entirely private mission to the ISS.
And it's a taste of things to come as countries make way for companies in space and the ISS is replaced with commercial space stations.
The low-Earth orbit economy is booming, says Phil McAlister, director of NASA's commercial spaceflight division.
"[Commercialisation is] something we've been working towards at NASA for many years, starting with cargo, then crew, and now private astronauts, and then hopefully soon commercial low-Earth orbit destinations in the 2030 time frame after the ISS retires," he said.
Let's fly through some facts about the mission and where it fits in with the future of space travel.
Astronauts or tourists?
The commander of the mission, Michael López-Alegría, is adamant the crew are astronauts, not tourists.
Axiom's vice-president of business development also happens to be an astronaut who has flown on three space shuttle missions and spent six months on the ISS in 2006.
"I'm excited about going back into space," he said.
Last year, a number of companies sent tourists who'd paid thousands of dollars on short stints either to the edge of space, or into orbit.
But the Ax-1 mission will be "very different," Mr López-Alegría claims.
Mr López-Alegría, mission pilot Larry Connor, and their crewmates Mark Pathy and Eytan Stibbe, will be working with a number of institutes on more than 25 projects, including stem cell research and experimenting with spacecraft self-assembly technologies.
They will also ferry completed experiments from the ISS back to Earth when they splash down 10 days after launch.
Will this just be a regular flight to the ISS?
Yes and no.
The crew will fly onboard the SpaceX Dragon capsule, which has now ferried three crews of astronauts to the ISS.
But this time, the take-off and landing logistics will be handled by Axiom and SpaceX, not NASA.
"Once it gets close, then NASA has responsibility for the safety of the ISS, as well as crew members.
"When they dock they become part of the ISS crew under charge of NASA."
Although NASA will be hands off for take-off and landing, Mr López-Alegría said flying for a company rather than a country didn't feel any different.
"The focus is always safety and mission success," he said.
"I do have some different responsibilities because my crewmates are my crewmates first and foremost, but they are also the company’s customers."
What kind of training have they had?
The crew has undergone at least 700 hours of training.
This included safety drills for the ascent and landing of the SpaceX capsule and on the ISS, as well as training to do their experiments onboard the space station.
Professional astronauts do about 45 weeks of training just to be chosen for the NASA astronaut program, and then a lot more training once they are selected to perform specialised tasks such as spacewalks.
But there are some overlaps between training regimes.
For example, the SpaceX training is the same for private astronauts as professional astronauts.
And even through Mr López-Alegría previously logged one of the longest stints on the ISS (215 days), he had to do a refresher course.
Once onboard, the crew will be shown around the station, go through the usual welcome ceremony and safety briefings, and get familiar with how to do daily tasks such as meal prep and using the water system.
And there will be some luxuries.
They will tuck into tasty meals designed by two-Michelin-star chef José Andrés.
On the menu is arroz Estelle Valencia, a classic Spanish rice dish; secreto de cerdo con pisto, a prized cut of Ibérico pork with tomatoes, onions, eggplant and peppers; and chicken and mushroom paella.
And if something goes wrong on the space station, they are not expected to fix anything, says Dana Weigel, deputy manager of NASA's ISS program.
"If the the toilet won't flush, one of our government astronauts will deal with that."
How many private missions are planned to the ISS?
This is the first of four missions Axiom has planned to the ISS (and just in case you're thinking you might like a ticket, the first three flights are already fully booked).
The second flight, projected to launch sometime in the second half of 2022 or first half of 2023, is also planned to spend eight days aboard the ISS.
The next two missions, to launch sometime after 2023, will spend 30 days on the ISS.
Eventually, Axiom plans to have at least one person living full-time in a commercial section of the space station.
In January 2020, Axiom won a contract to build two inflatable modules to add to the space station.
The company plans to send the first module up in 2024. The idea is that the modules will become part of a commercial standalone space station when the ISS is retired in 2030.
Three other companies, Blue Origin, Nanoracks and Northrop Grumman, are also in competition to design a commercial space station to replace the ISS.
The first flight would give Axiom the opportunity to test out its business case for commercial operations, said Aude Vignelles, chief technology officer of the Australian Space Agency, which is not involved in the mission.
"It's a bit of a test of the market and what people expect because when they come back, they will say, 'this was great, this was not so great' and [the company] may have to think a bit more about their design or proposition."
It will also be a test of how commercial crews interact on the space station and provide some insight into the design of the future modules, she added.
"When you look at how busy [the ISS] is, you have to be careful not to bump into anything or not to interrupt other missions.
"It's not been designed for non-professional astronauts and I think that's the challenge for Axiom — that they are making sure they are designing something that is made for anyone to go to."
What will the future of commercial space look like?
NASA is keen to open up the ISS to companies and support future space ventures.
Ms Vignelles said the commercialisation of low Earth orbit space also opened up opportunities for Australia to provide expertise in areas such as communications, navigation, monitoring and medicine.
There may even be an astronaut program in the future.
But the commercialisation of space also comes with a downside.
"The low Earth orbits are more and more contested so we are going to have to be very cautious ... making sure we know what is in orbit and making sure there are no collisions and monitoring what's happening," she said.
"There are more and more manoeuvres that the space station needs to do to avoid debris.
"If we are not careful ... and put some rules around spacecraft being launched ... we may reach a stage where it's going to be difficult to use any orbit."
Andrew Dempster, director of the Australian Centre for Space Engineering at UNSW, agreed.
"The orbit that the space station is in is getting more crowded," Professor Dempster said.
SpaceX, for instance, is putting up Starlink satellites above the space station, and they must also come back down through that zone when they deorbit.
"If there were lots of habitats and lots of low Earth orbit satellites, then there are likely to be more collisions," he said.
The Chinese government recently complained that SpaceX Starlink satellites had come close to its space station.
"If we start having collisions happening in low Earth orbit, that will set us all back."
