The Environmental Impact of Space Launch: Analyzing Carbon Emissions and Pollution

The space industry is experiencing a significant growth in recent years, with advancements in technology and ambitious plans for space tourism, Moon landings, and even Mars exploration. However, this progress comes at a cost, as the environmental impact of space launches is becoming a matter of concern. As the number of rocket launches increases, so does the environmental footprint of the industry. This article examines the different aspects of the environmental impact of space launch, focusing on carbon emissions, pollution, and potential damage to the ozone layer.

Rocket Propellants and Their Environmental Impact

Rocket propellants play a crucial role in determining the environmental impact of space launches. Each type of propellant comes with its own advantages and disadvantages in terms of efficiency, safety, and environmental impact.

The SpaceX Starship spacecraft stacked on the Super Heavy booster. (Image credit: Jim Watson/Getty Images)

UDMH: The "Devil's Venom"

Unsymmetrical dimethylhydrazine (UDMH) is a highly effective rocket propellant used by many rockets, including the Soviet Union's Proton rockets. It is known for its ability to be stored at room temperature and for releasing a significant amount of energy. However, UDMH has been dubbed "devil's venom" due to its highly toxic nature. This propellant is highly carcinogenic to humans and has been blamed for turning vast areas of the Kazakh Steppe into an ecological disaster zone. UDMH spills from the first and second stages of Proton rockets have poisoned the soil for decades, causing long-lasting environmental damage.

Solid Rocket Motors: Particle Factories and Ozone Holes

Solid rocket motors (SRMs) are commonly used in heavy-lift rockets, such as the solid rocket boosters of NASA's space shuttles. These motors burn a mixture of aluminum and ammonia, producing reactive chemicals like hydrochloric acid and aluminum oxide. These substances can mix with water from the rocket's cooling systems, creating clouds that spread into the surrounding environment, affecting soil and water quality, and damaging vegetation.

Space shuttle launches have also been linked to localized ozone holes in the rocket's wake, although these holes heal quickly and do not have a significant global impact on the ozone layer. However, aluminum oxide particles from the exhaust of SRMs can affect the amount of heat that reaches Earth's surface, potentially triggering temperature changes.

Hybrid Rocket Engines: The Not-So-Clean Newcomer

Hybrid rocket engines burn solid fuel with liquid or gaseous oxidizer, generating a significant amount of soot as a byproduct. These engines, used by companies like Virgin Galactic for their suborbital space planes, may be simple and safe to operate but come with environmental concerns. The soot particles generated by hybrid rocket engines can also affect how the atmosphere absorbs heat, potentially impacting Earth's climate.

ULA’s Delta IV Heavy rocket uses a combination of liquid hydrogen and liquid oxygen. (Image credit: ULA)

Kerosene: Reliable But Sooty

Rocket Propellant 1 (RP-1), a refined version of aviation fuel kerosene, is a popular rocket fuel known for its stability and energy output. However, RP-1-powered engines produce soot, contributing to atmospheric pollution. The amount of pollution released depends on both the fuel and the construction of the engine itself, making it difficult to determine which rockets are dirtier than others.

The Ozone Layer and Space Travel

The projected increase in space travel has raised concerns about its potential impact on Earth's ozone layer, which protects life on our planet from harmful ultraviolet radiation. Researchers have found that a 10-fold increase in hydrocarbon-fueled launches could damage the ozone layer and change atmospheric circulation patterns. This could lead to increased harmful UV radiation exposure for people in the Northern Hemisphere and have profound consequences on the environment.

New Zealand's Space Sector and Environmental Regulation

New Zealand's emerging space sector is experiencing growth due to its desirable location for space operations, skilled workforce, and strong government financial incentives. However, there are challenges related to the environmental impact of space activities, including space debris and the effects of climate change on space operations. This presents an opportunity for New Zealand to integrate international best practices for environmental sustainability at a foundational level, potentially using tools like the European Space Agency's Life Cycle Assessment (LCA) Tool and Eco-design Framework.

Case Study: Environmental LCA for a New Zealand CubeSat

A case study on an environmental LCA for a New Zealand-designed and launched CubeSat highlights the potential for identifying environmental hotspots during the design and launch phases. The study points out the need for further research on the application of LCA to space activities.

Seeking Greener Rocket Fuels and Technologies

Researchers are exploring alternative rocket fuels and technologies to reduce the environmental impact of space launches. Some promising options include:

The Baikonur launch site created a large zone of pollution. (Image credit: Bill Ingalls/NASA)

Liquid Oxygen/Liquid Hydrogen: A Clean Option

Liquid oxygen/liquid hydrogen (LOx/LH2) is an environmentally friendly rocket fuel option, as its exhaust is primarily water vapor. It has a minimal impact on the ozone layer and climate. However, due to its low energy density, LOx/LH2 often requires additional solid boosters for heavy-lift rockets.

Methane: A Promising Fuel with Possible Leakage Issues

Methane-based rocket propellant is an upcoming technology that may help the spaceflight industry transition away from more polluting SRMs. Methane burns more cleanly than RP-1 and provides more energy than LOx/LH2. However, methane is a potent greenhouse gas, and leaks from gas pipes during transport could contribute to climate change.

Biofuels: A Little-Explored Dark Horse

Several rocket start-ups are experimenting with sustainable alternatives to RP-1 made from waste products or biomass. Biofuels, such as biopropane and Ecosene, have the potential to produce fewer emissions compared to traditional rocket fuels. More research is needed to determine the viability and environmental impact of biofuels for space launches.

The Future of Space Launch and the Environment

As the space industry continues to grow, it is vital to consider the environmental impact of space launches and explore ways to minimize their ecological footprint. This includes researching alternative rocket fuels and technologies, as well as implementing best practices for environmental sustainability within the industry.

It is essential for governments, space agencies, and private companies to collaborate in addressing the environmental concerns of space launches. By working together, we can ensure that the progress of space exploration does not come at the expense of our planet's health and well-being.

Conclusion

The environmental impact of space launches is an important issue that warrants careful consideration and research. As the space industry continues to expand, it is essential to find ways to minimize the carbon emissions and pollution associated with rocket launches. By exploring alternative rocket fuels and technologies, implementing best practices for environmental sustainability, and collaborating with international partners, we can work towards a more environmentally friendly future for space exploration.