Living in the middle of a new space race is exhilarating, but this push to carry mankind to the stars runs counter to the worldwide effort to reduce carbon emissions and make the earth more sustainable. Between 2021 and 2031, the space tourism business is estimated to generate $2.58 billion. At the moment, a single rocket launch may produce up to 300 tons of CO2, which is then directly injected into the upper atmosphere.
Over the next decade, space tourism and flying will develop at an exponential rate. How might biofuels help make the race to interstellar travel more sustainable?
More Space Flights Day after day
During the 1990s and 2000s, the globe was fortunate to see a number of rocket launches per year. The majority of these were satellites transporting supplies or personnel to the International Space Station. SpaceX launched 26 rockets in 2020, with the number projected to rise. This does not include the Starship test flights or SpaceX’s goal of launching 15 million rockets each year.
With 16.9 million flights in 2020, this might match the condition of the commercial airline sector. This industry intends to transport a billion people on planes powered by alternative fuels by 2025, but it may face fierce competition.
The greater the number of flights, the more CO2 these launches will emit into the sky. As long as they rely on conventional fuels like kerosene and hydrogen, this will present issues. When everyone is so thrilled about the prospect of sending humans to Mars or the moon, it’s easy to ignore the environmental consequences of space travel. Nonetheless, each launch adds a small amount of CO2 to the atmosphere, making it increasingly difficult to avoid a climatic calamity.
Getting Rid of Hydrazine
Hydrazine is a common rocket fuel because it burns well in the presence of oxygen or, in the case of rocket launches, oxidizers. Unfortunately, it is also extremely flammable, prone to spontaneous explosions, and extremely hazardous to people. Working with hydrazine necessitates a number of stringent safety measures. A green biofuel might be the solution, allowing spacecraft to be fuelled during the production process rather than waiting until they arrive at the launch facility.
NASA launched the Green Propellant Infusion Mission (GPIM) in 2019 to demonstrate a green alternative fuel for spacecraft. The AF-M315E lasted 13 months in low earth orbit, powered by a hydroxyl ammonium nitrate fuel mixture and an oxidizer. GPIM’s fuel is denser than its volatile relative and can give higher thrust per quantity of rocket fuel, in addition to missing the toxicity of hydrazine. It also doesn’t require a heater to keep it warm in the frigid cold of outer space.
Producing biofuel may be difficult, especially when it comes to something that must resist the rigors of space flight. When utilized alone, traditional biofuel manufacturing processes — fermentation and heating — have limitations. Because the bacteria and enzymes utilized in this method cannot convert lignin into alcohol, fermentation produces a biofuel that only absorbs around 35% of the substance’s stored potential energy.
Heating the materials in a low or no-oxygen atmosphere degrades them into bio-oil, which may then be processed into additional biofuel products. Nonetheless, careful temperature and pressure control are required at this process. If the liquid biofuel is exposed to too much heat, it will freeze into carbon coke, rendering it virtually unusable for biofuel production.
Combining the two types of manufacturing — a technique known as catalytic hydropyrolysis — might produce the kind of yields needed to power the globe and transport the human race to the stars.
Choosing Low-Carbon Fuels
The primary fuel for a Falcon 9 launch is rocket-grade kerosene, which is augmented by supercooled liquid O2 as an oxidizing agent as it exits the atmosphere. This emits massive volumes of CO2 into the high atmosphere. Even hydrogen-powered rockets can have an influence on the earth by releasing water particles into the upper atmosphere, where they condense into clouds.
Orbex Prime has chosen a low-carbon fuel as well as a one-of-a-kind launch mechanism that might transform the way the space industry enters orbit. The Orbex Prime launch vehicle will lift off horizontally from an aircraft carrier, producing fewer emissions than a vertical takeoff. This, combined with the low-carbon fuel, has the potential to cut CO2 emissions from each launch by 96%. Instead of emitting 300 tons of CO2, the Orbex Prime rockets will emit just 13.8.
Investing in the Future
Finding green fuel options for space flight is about more than simply finding a better means to reach the stars. It is critical for environmental protection to ensure that there will be a planet to launch from in a couple of hundred years.