


Why space flights’ green credentials don’t fly

The Lex Column

After years of work and billions of dollars, Sir Richard Branson and Jeff Bezos are climbing into their own spacecrafts to take trips to the edge of space to prove that space tourism is a viable business.

Both claim green credits for their endeavours.

Richard Branson is due to take off on Sunday. Getty

Branson’s space flight company Virgin Galactic says it has a focus on “environmental sustainability”. Bezos believes space travel provides a potential solution to climate change.

But the power required to fly there deserves examination.

Rocket launch emissions can include black carbon (aka soot) as well as CO2. The higher a spacecraft flies, the more fuel it requires. The Space Shuttle orbiter needed almost 720,000 kilograms of liquid fuel and 500,000 kilograms of solid rocket fuel to reach space.


Suborbital space flights by Virgin Galactic and Bezos’ Blue Origin require less power. Blue Origin’s reusable New Shepard uses a liquid hydrogen-fuelled engine to travel more than 60 miles (about 100km) above Earth. Hydrogen fuel does not emit carbon — though its production often does.

The VSS Unity rocket plane that Branson will travel on is air-launched and burns solid fuel for one minute to fly 50 or so miles above Earth.

Virgin Galactic likens the carbon footprint for passengers to a business class return ticket on a trans-Atlantic flight. Using data from the International Civil Aviation Organisation, that means about 1238 kilograms of CO2 per passenger.


The journey lengths are not the same, however. A return trans-Atlantic flight covers about 11,100 kilometres. Virgin Galactic’s trip up and down adds up to about 100 miles (160km).

Per passenger, per kilometre, the CO2 emissions are 12 kilograms of CO2 for Virgin’s space trip versus 0.2 kilograms of CO2 for the commercial airline flight.

The overall CO2 footprint of space flights appears modest, mostly because rocket flights are still rare. But if space tourism takes off, expect more focus on the environmental impact of this new hobby for the wealthy.

Financial Times

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