People who sign up with space tourism companies for a trip beyond the Earth may be unprepared for the rigours of spaceflight, according to a NASA astronaut.
To date, only the Russian Space Agency, Roscosmos, has taken tourists into space, between 2001 and 2009, at a cost between USD 20 and 40 million.
However, aerospace companies like Blue Origin, Virgin Galactic and SpaceX are hoping to launch commercial flights within the next decade.
Hundreds of people including Hollywood actors like Angelina Jolie, Kate Winslet and Leonardo DiCaprio, have already bought tickets.
Nasa astronaut Anna Fisher, who became the first mother in space, has warned many are unprepared for the rigours of spaceflight and the toll it will take on their bodies.
Fisher said she was sick for the first two days of her mission on the Discovery space shuttle in 1984, expressing concern that people paying hundreds of thousands of pounds did not fully appreciate what might happen.
"It's not like riding a commercial aircraft, not at all, and I can see all these problems with people up there and throwing up and messing up somebody's flight that they paid USD 250,000 for," Fisher was quoted as saying by 'The Telegraph'.
The Apollo 8 crew were the first astronauts to report space sickness in 1968, and by Apollo 9 the crews were feeling so bad that their spacewalk had to be rescheduled.
NASA's training aircraft where astronauts can experience weightlessness is colloquially known as the 'vomit comet' because it makes people feel so ill.
It is widely known that microgravity seriously impacts metabolism, heat regulation, heart rhythm, muscle tone, bone density, eyesight, and the respiration system.
In 2016, research from the US also found that astronauts who travelled into deep space on lunar missions were five times more likely to have died from cardiovascular disease than those who went into low orbit or never left Earth.
Last year Russian scientists found microgravity causes such alarming changes to the immune system, that astronauts would struggle to shake off even a minor virus, like the common cold if they became infected.
Space agencies are particularly worried by solar and cosmic radiation and have still not come up with a way to protect astronauts on lengthy visits to Mars or the Moon.