Billionaire businessman Jeff Bezos is launched with three crew members aboard a New Shepard rocket aboard the world’s first unmanned suborbital flight from Blue Origin Launch Site 1 near Van Horn, in Texas, July 20, 2021.
Captain Joe | Reuters
The space industry is moving forward after decades of stagnation.
Powered largely by Elon Musk’s SpaceX and China’s rapidly developing space programs, the world recorded 114 orbital launches in 2018 – the first triple-digit display since 1990. This year, orbital launches are on track to go over 130 for the very first time. 1970s. And that number doesn’t include recent suborbital sightseeing tours of Blue Origin by Jeff Bezos and Virgin Galactic by Richard Branson.
Between NASA’s plans for a lunar return, SpaceX building a massive “mega-constellation” of internet satellites, China building a space station, and suborbital companies sending crews of tourists to the edge of space, launches may soon become daily. . can.
But will the new space boom come at the expense of the planet?
Ian Whitaker, Senior Lecturer in Space Physics at Nottingham Trent University in the UK, says: “While we clearly need space launches and satellites, when it comes to things like space tourism, you start to think about the environmental impact. “Let’s do it.”
Researchers are scrambling to figure out how Earth might react to the more inflated rocket exhaust plume by studying the composite mixture of carbon dioxide, soot, alumina and other particles emitted by a wide variety of rockets. spit collectively.
So far, the nascent space industry has not seriously endangered the environment and is likely to thrive. Whether or not that changes as the new space race intensifies, is for everyone to guess.
“I don’t think we know enough at this point about what the future holds in store for us,” says Martin Ross, atmospheric scientist at The Aerospace Corp. “We don’t have that information yet.”
Carbon dioxide and the impact on climate change
As the world grapples with the transition from fossil fuels, the rise of a new industry – especially one involving giant clouds emanating from powerful engines – can seem unsettling.
Most rockets emit more carbon which warms the planet than many airplanes. Living a few minutes of weightlessness aboard the Virgin Galactic space plane would increase a carbon footprint equivalent to a business class flight across the Atlantic, and an orbital launch of SpaceX’s next fully reusable Starship would take nearly three years to complete. fly a plane continuously. will emit that much carbon dioxide. , according to a calculation on the back of the Whitaker envelope.
A spokesperson for Virgin Galactic said the company “is exploring opportunities to offset carbon emissions for future customer flights.” Although SpaceX did not comment directly on carbon emissions, Musk supported the carbon tax policy. Blue Origin said its New Shepard rocket uses carbon-free fuels such as hydrogen and oxygen.
But there are far more commercial aircraft flights than space launches – 39 million compared to 114 in 2018 respectively – too numerous for the space industry to grasp even the most ambitious scenarios. Today, rockets collectively burn about 0.1% fuel compared to airplanes, which makes a rounding error when comparing their carbon emissions.
However, Whitaker points out that such a calculation ignores the unknown but potential carbon footprint, which is a substantial carbon footprint to produce, transport and cool the ton used in space launches.
“While it doesn’t fit in with aviation, it’s still a great addition,” he says.
To achieve carbon neutrality, he hopes the industry will follow Blue Origin’s lead and use carbon-free fuels as well as green operations by locally producing fuel from renewable energy sources.
what rockets release into the atmosphere
“If the CO2 isn’t where the action takes place, it’s the particles,” says Ross, who has studied the environmental impacts of the launch.
The bright flames emanating from the rocket engine indicate that the vehicle’s combustion produces soot, technically known as “carbon black.” Any rocket that burns a carbon-based fuel like kerosene or methane injects these particles directly into the upper atmosphere, where they are likely to circulate for four to five years.
There, the growing layer of soot acts like a beautiful black umbrella. It absorbs solar radiation and effectively blocks sunlight from reaching the planet’s surface, just as proposed geoengineering programs could be used to temporarily cool the Earth. Luminous alumina particles emitted by powder rocket engines used by NASA’s upcoming space launch system and China’s Long March 11 vehicle amplify the phenomenon by reflecting sunlight.
The effects of this unintended experience are unknown – other than that, they can be substantial. A simple simulation performed by Ross and a colleague in 2014 found that the primary cooling effect of dozens of rocket launches already matched the warming effect of carbon dioxide released by millions of commercial flights.
This does not mean that the space industry is reversing the environmental consequences of flight. Infusing the atmosphere with new particles has complex effects, says Ross. For example, their rough model revealed that the rocket cooled some places down to 0.5 ° C, while warming the Arctic by more than 1 ° C. And the simulation did not attempt to include side effects, such as whether the launch would create or kill clouds. Ross says more sophisticated modeling could reveal that exhaust particles make equilibrium warming worse.
Other emissions and ozone
Space launches are also of concern to some researchers because rockets expel their exhaust gases directly into the stratosphere, which houses the protective ozone layer that blocks harmful ultraviolet light.
Most powder rocket engines emit particles of alumina and chlorine gas, which promote chemical reactions that break down ozone into molecular oxygen. SpaceX and Blue Origin have switched to liquid fuels, which are less harmful but still contain byproducts including water vapor and nitrogen oxides that can deplete ozone during years when it circulates in the high. atmosphere. Eh.
“They are not harmless,” says atmospheric researcher Alois Marais of University College London. “They have an effect on the environment.
Marais is working on a forecast of how the current portfolio of rocket fuels could thin the ozone layer in the not-so-distant future. He studied the effects of current launches and a speculative scenario in which space tourism proves to be popular and reliable, supporting a few suborbital launches every day and one orbital launch every week.
Calculations need to be verified before publication, Marais says, but while preliminary results suggest today’s launches have little effect on ozone, a burgeoning space tourism industry could start to change that. .
“It’s an impact big enough that I think we might be concerned if the industry grows beyond what we anticipate,” she said.
How often companies will launch in the future remains uncertain. Virgin Galactic says it hopes to eventually operate 400 flights per year. SpaceX envisions Starship projecting passengers between major cities in less than an hour, competing with commercial airlines.
Reconciling spatial progress and environmental concerns
Access to space has revolutionized weather forecasting, communication technologies, and the ability of researchers to understand how human activities have altered Earth’s climate. It has enabled space facilities such as the International Space Station and a fleet of space telescopes to conduct transformative fundamental research.
In the future, a thriving space industry could unlock hands-on projects ranging from clean solar and space energy to asteroid mining, as well as supporting solar system life research and other scientific endeavors. .
Researchers like Ross don’t want to stop this progress. Instead, they hope to help make this possible by identifying potential environmental issues in advance. Today’s embryonic space industry is mostly harmless, and Ross suggests that an environmental research program could help it stay that way as it matures.
Stratospheric planes can directly sample rocket plumes to find out what they are spitting, while satellites and ground observatories examine the atmosphere for the short, medium and long term effects of the launch. There are also unknown effects of dormant satellites “burning” and dumping tons of metal particles into the upper atmosphere. Supercomputers can run deep simulations to determine what levels and types of space activity can be safely conducted.
“We want to avoid a surprising future,” says Ross. “We would like to say now that the space industry can move forward in a sustainable manner.”