The commercial space race is heating up, with billionaire Richard Branson the latest to announce tourist flights – but ordinary travellers will stay grounded due to costs that are likely to soar beyond stratospheric.

Speaking on ABC’s 7.30 on Monday, Mr Branson said he hoped tourist flights could be a reality by the end of this year.

But when asked about the cost of travel, he remained tight-lipped.

“I’m not going to give a figure because otherwise nobody will go up in the early flights,” Mr Branson said.

Previously, Mr Branson estimated that initial flights will cost $US250,000 ($349,000) per person, claiming that it was vastly cheaper than Russian space flights costing $US30 million.

‘A few minutes in space’  

Monash University astronomer Dr Michael Brown said it was likely that passengers aboard Virgin Galactic flights will have only a “few minutes in space”. 

“The passengers will have a few minutes of weightlessness, then actually seeing the curvature of the Earth and most of the flight is getting up there and then gradually gliding back down,” Dr Brown told The New Daily. 

“If you fly someone into orbit, then you need to get them at a much greater speed, which requires more energy and re-entry with a proper heat shield.”

He said space tourism wasn’t the most sustainable industry.

“I don’t know if Virgin Galactic is offering carbon offsets for their flights – if they are they have to be quite spectacular because to fly someone to space uses quite a lot of energy. To fly someone into orbit, then that requires even more energy.”

‘600 people booked’

Virgin Galactic’s reusable spacecraft, SpaceShipTwo, is designed to carry six passengers on a suborbital flight, reaching an altitude of 100 kilometres above Earth.

According to the company, the cabin is designed to “optimise the out-of-seat, zero-gravity experience for our astronauts”.

According to the ABC, more than 600 people have booked tickets.

With a wingspan of eight metres, the marvel of technology can alter its configuration at peak altitude to allow for re-entry into the atmosphere.

‘Amateur-hour space flight’

Virgin Galactic carried out four successful tests in 2018, after its original spaceship crashed in 2014, killing one of the two pilots.

Virgin Galactic’s Unity on a test flight over the Mojave Desert in the US. Photo: AAP

After the 2014 tragedy, Time magazine editor Jeffrey Kluger referred to Virgin Galactic as “amateur hour” and Mr Branson as “a man driven by too much hubris, too much hucksterism and too little knowledge of the head-crackingly complex business of engineering”. 

But last year, the SpaceShipTwo rocket ship made it to the edge of space and back, reaching an altitude of 82,683 metres – officially entering space, according to US standards.

Space race heats up

Elon Musk’s SpaceX has its sights set on the moon for its space tourism project, with Japanese billionaire Yusaku Maezawa scheduled to enter space in 2023. 

The company’s Big Falcon Rocket will take about eight creative people, including artists, designers and architects, on a week-long journey around the Moon without a lunar landing – the first-ever private commercial trip of its kind. 

While at this stage it’s unclear how much a trip will cost, Musk has previously said it’s “a lot of money”.

The rocket is still under construction and will be subject to several unmanned test launches before it takes any passengers.