NASA’s Artemis I mission ushered in a new era of space exploration last month, with the launch of the first in a complex series of missions to enable humans to explore the moon and Mars.
Despite challenges with supercooled liquid hydrogen ahead of its November 16 launch, the mission successfully used the universe’s lightest and most abundant element to generate enough energy to power four rockets. 2 million pounds of thrust. The other major by-product is steam.
That’s good for planet earth, especially when compared to rocket launches based on a popular alternative: kerosene-based propellants. In case spacea Falcon 9 flight emits about 336 tons of carbon dioxide—the equivalent of a car traveling around the world 70 times—according to John Cumbers, former NASA synthetic biologist and CEO of SynBioBeta .
Burning liquid hydrogen is far from perfect: Its production is often a process that uses a lot of fossil fuels. But green hydrogen projects are trying to improve its sustainability through the use of renewable energy.
NASA has used liquid hydrogen as a fuel for decades, and will likely continue to do so, both because of its effectiveness and because Congress has mandated that the space shuttle-powered Artemis mission, designed around the use of hydrogen. But it is just one of many entities in the space sector today, and private companies are expected to play an increasing role in space tourism and satellite launches.
Environmental considerations become increasingly important as space travel develops. Cumbers predicts that humans will launch 10 times more rockets in the next 10 to 20 years than we do today.
Last year, the global space economy reached $469 billion, up 9% from 2020, according to space fund. In the first six months of this year, a record 72 successful rocket launches put 1,022 identified spacecraft into orbit, more than the total placed in the first 52 years of the Space Age, the organization said. know.
Aviation accounts for about 2.5% of all carbon emissions on earth, while rocket launches contribute a much smaller share. But as the new space race unfolds and more rockets are launched than ever before, the quest for sustainable rocket fuel is well underway.
Race to create green rocket fuel
While green rocket fuel isn’t a planetary saver, it’s one small step humanity can take to achieve a net-free future.
There are several efforts underway to produce rocket fuel in a more environmentally friendly manner. Energy startup Green Hydrogen International is developing a green hydrogen project in South Texas. Researchers at the German Aerospace Center are working on a fuel that produces only nitrogen, oxygen and water when heated. Canadian company Hyox is developing technology for the production of net aviation fuel and rocket fuel that will use solar energy and low-cost electrolysis to produce methane and kerosene, both of which can rocket into space.
The New York-based Aviation Company is working with direct air capture, a technology that removes carbon dioxide from the air. The company mixes that CO2 with renewable-generated hydrogen to create Rocket Propellan-1 (RP-1), the kerosene used by Space X’s Falcon 9 rocket. only carbon negative that could one day be replicated on Mars—where the atmosphere is mostly composed of carbon dioxide—to fuel return trips. Therefore, fuel will not have to be transported from Earth for missions to the red planet.
Aviation Company CEO Gregory Constantine says the company’s process removes about 2.8 kilograms of CO2 from the air per liter of RP-1, while traditional fossil fuel-fuelled manufacturing processes waste more than 3 kg of CO2 per liter.
Black carbon and other emissions
Producing rocket fuel in an eco-friendly way is only part of the battle. Kerosene fuel and methane also deposit black carbon—or soot from combustion—into the upper atmosphere, where it warms the air for years.
To get rid of the black carbon problem, rockets can ignite hydrogen, but that’s a technical challenge because it has to be kept at very cold temperatures. The Artemis program has been plagued by liquid hydrogen problems. Meanwhile, methane may be a better choice because it produces less soot than kerosene and can be stored at higher temperatures.
“Liquid methane is where everyone is going,” said Matt Oehlschlaeger, professor of aerospace engineering at Rensselaer Polytechnic Institute.
There is still a long way to go before rocket fuel created using environmentally friendly methods becomes commonplace.
We believe these technologies should be applied to more pressing problems, namely industry, before emissions are relatively low like rockets.
—Mo Islam, head of research at Republic Capital, early investor in SpaceX and investor in Axiom Space
Mo Islam, head of research at Republic Capital, an early investor in SpaceX and an investor in Axiom Space, said: “Renewable fuels, whatever the application, are still very much alive. new. “We believe these technologies should be applied to more pressing problems, namely industry, before emissions are relatively low like rockets.”
Islam says many stakeholders need to come together to accelerate the development of renewable fuels.
“We need coordination among policymakers, technologists and businesses to properly fund R&D on these fuels,” he noted. “Once we have a proof of concept, we can start thinking about deploying it on a large scale—first existing ground processes, then rockets.”
The cost of direct air capture will also need to fall before that technology can become mainstream. For direct air capture of RP-1 and methane-based fuels to be comparable in cost to fossil-based fuels, the cost would have to be reduced from $650 to $1,000 per ton of carbon dioxide. down to $100 per ton, according to Glenn Martin, CEO of Hyox.
“This is where the technology curve is headed,” he said.
Lower cost, greater demand
Meanwhile, the cost of rocket launches is also falling. When adjusted for inflation, the cost of heavy launches into low-Earth orbit has fallen from $65,000/kg to $1,500/kg since the 1960s, according to an analysis of Chinese data Center for Strategic and International Studies. McKinsey. The key drivers are computer-aided design, 3D printing, reusable components, new commercial launch service providers, and increased launch frequency.
Lowering costs could boost demand for satellite-based services, making the need for sustainable rocket fuel all the more urgent. Some of those satellites could help fight climate change, even if they need emissions to launch.
Conor Tomac, process engineer specializing in gas, fuel and chemicals at Black & Veatch notes: “Satellites in space can be used to monitor trends in Earth’s water resources or to detect emissions leaks, which can then be used to reduce emissions sources.” .
Jory Bell, general partner at Playground Global, a venture capital firm focused on cutting-edge technologies, says dedicated earth-observing satellites have been able to identify methane super emitters yet. known in advance, helps facilitate mitigation.
“Using space to observe and understand the earth,” says Bell, “will be an important part of cleaning up the climate mess we are in.”