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Scientists are concerned over the climate impact of space tourism

Space flights emit around 25 times more carbon per passenger than a long-haul commercial airline flight

Richard Branson and Jeff Bezos' recent flights to space have ignited concerns in the scientific community about the long-term impact of commercial space tourism on the Earth's atmosphere and climate.

After years of waiting, Richard Branson - founder of Virgin Galactic - ascended 80 km to reach the edge of the space in a VSS Unity spaceplane, on the 11th July.

Ex-Amazon CEO Jeff Bezos did the same in a Blue Origin craft, reaching higher altitudes (about 120 km), a few days later.

While these milestones represent more than just a technical accomplishment, scientists are concerned that the growing numbers of rocket flights could harm Earth's atmosphere in the longer term; specifically the ozone layer in the upper atmosphere.

In the case of the romantically named SpaceShipTwo - the vehicle used by Branson - the flights are powered by a hybrid engine that burns rubber and leaves behind a cloud of soot.

"Hybrid engines can use different types of fuels, but they always generate a lot of soot," Filippo Maggi, associate professor of aerospace engineering at Politecnico di Milano, Italy, told Space.com.

"These engines work like a candle, and their burning process creates conditions that are favourable for soot generation."

In 2010, a study found that the soot released by 1,000 space tourism flights could warm Antarctica by nearly 1 degree Celsius.

Virgin Galactic has said that it aims to launch 400 commercial space flights annually.

So far, the impact of rocket launches on the atmosphere is insignificant because of the limited number of launches happening worldwide, said Martin Ross, an atmospheric scientist at the Aerospace Corporation.

"The amount of fuel currently burned by the space industry is less than 1 per cent of the fuel burned by aviation," Ross noted.

"So there has not been a lot of research, and that makes sense. But things are changing in a way that suggests that we should learn about this in more detail."

Eloise Marais, an associate professor of physical geography at University College London, has calculated that every space flight carrying four passengers results in about 300 tonnes of CO2, or 75 tonnes per passenger, compared with up to three tonnes per passenger on a long-haul commercial airline flight.

"[Commercial space travel] doesn't need to grow that much more to compete with other sources [of carbon]," Ms Marais told The Guardian.

Virgin Galactic said last week that its carbon emissions during a space flight are nearly equivalent to a business-class ticket from New York to London.

The company told AFP that it has taken a variety of measures to offset the carbon emissions from its test flights. It also claims to be exploring opportunities to offset the carbon emissions from future commercial flights.

Jeff Bezos argues that Blue Origin craft uses liquid hydrogen and oxygen fuel, which is less damaging to the environment.

Experts, however, believe that those flights could still have significant effects on the atmosphere.

In 2019, Amazon announced a string of measures aimed at lowering its greenhouse gas emissions.

The company committed to using only energy derived from renewable sources by 2030, with a goal of 80 per cent renewables by 2024, and to be carbon neutral by 2040 - a decade before the Paris Accord target for net zero emissions.

It also promised to invest $100 million in restoring and protect forests, wetlands and peatlands in partnership with environmental charity The Nature Conservancy.

Computing will run the Tech Impact Conference this year, exploring the relationship between tech and the climate - including case studies about the road to net zero, how to go green in your data centre and supply chain, and how to make small changes with a big impact. For those who are passionate about the planet - and those who are more wary - there has never been a better time to get involved.

Scientists are concerned over the climate impact of space tourism

Space flights emit around 25 times more carbon per passenger than a long-haul commercial airline flight

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