SpaceX has succeeded in revolutionizing and expanding commercial spaceflight through its launch services for satellites and spacecraft, reusable rocket technology, and deployment of large-scale commercial spaceflight infrastructure. Furthermore, through its satellite internet service Starlink, it now has the largest constellation of low earth orbit or LEO satellites. The company has a bold ambition of colonizing Mars and ushering in a new era of space exploration. However, despite claiming that it aims to contribute to the overall vision of a spacefaring civilization, its ongoing operations and further technological pursuits have environmental implications.
Creating the Future of Space Travel at the Expense of the Environment: Understanding the Environmental Impacts of SpaceX
Emissions from Rocket Launches
The Raptor engines used in the spacecraft Starship and its Super Heavy Booster use liquid oxygen and liquid methane or methanol as fuel. These are not toxic to the environment. However, the Merlin engines used in the Falcon 9 reusable launch vehicles use liquid oxygen and rocket-grade kerosene. Kerosene is a fossil fuel that releases greenhouse gasses when burned.
Even the highly refined rocket-grade kerosene releases carbon dioxide and black carbon or soot during combustion. Rocket exhaust also contains other compounds like nitrogen oxides. It is true that the greenhouse gas emissions from spaceflight are only equivalent to 1 to 2 percent of the carbon footprint of aviation but the fact remains these emissions are pollutants.
Starships are still problematic. Andrew Wilson, assistant professor in environmental management at Glasgow Caledonian University, told Space.com that a single Starship launch releases 76000 metric tons of carbon dioxide equivalent. This is 2.72 times higher than the emissions from a single Falcon 9 launch and about 0.96 higher than a Falcon Heavy liftoff.
The emissions of companies like SpaceX and their subsequent environmental impacts increase with scale. The non-profit U.S. Public Interest Research Groups that planned a series of launches required for deploying a mega-constellation of satellites would release soot in the atmosphere equivalent to 7 million diesel dump trucks circling the globe each year.
Atmospheric physicists C. Voigt et al. also explained that rockets are the sole direct human-made source of pollution in the upper atmosphere and that emissions released high in the stratosphere can alter the composition of the upper atmosphere. These include ozone layer depletion and the formation of mesospheric clouds from iron and water vapor concentrations.
Problems With Starlink Satellites
Starlink satellites are not permanent. Hence, once they reach the end of their useful lives, they are decommissioned, leave the orbit, and burned up in the atmosphere. These reentries are increasing because SpaceX is decommissioning its first-generation satellites. Reports have noted that there were 120 Starlink satellites that were decommissioned in January 2025 alone.
Note that satellites are engineered to disintegrate once they reenter the atmosphere. The purpose is to ensure that most of their mass vaporizes before reaching the surface. However, based on more recent studies, aluminum oxide is released into the atmosphere during disintegration. This compound can deplete the ozone in the stratosphere and disrupt the magnetic field.
Researchers J. P Ferreira et al. noted that the re-entry of a satellite weighing 250 kilograms can produce around 30 kilograms of aluminum oxide nanoparticles. These can persist in the atmosphere for decades. Estimates from A. K. Jain et al. indicated that alumina particles suspended in the atmosphere can have a limited cooling effect. This can disrupt weather systems.
Available data indicated that approximately 41.7 metric tons of aluminum were released from all low earth orbit satellites that reentered the atmosphere in 2022. This is 29.5 percent higher than the natural contribution from micrometeoroids. These reentries contributed to the accumulation of approximately 16.6 metric tons of aluminum oxide within the mesosphere.
Furthermore, based on the available scenarios involving mega-constellations of low earth orbit satellites, the forecasts from J. P Ferreira et al. also revealed that excess aluminum in the upper mesosphere could surpass natural levels by more than 640 percent annually. This is equivalent to the release of about 360 metric tons of aluminum oxide cluster each year.
Other Issues With Launch Operations
Both successful and failed SpaceX launches have a range of environmental impacts that warrant consideration. Each launch can disrupt wildlife behavior and habitats because of noise pollution. Materials like sizeable concrete fragments and stainless steel sheets are tossed thousands of feet away along with a plume cloud of pulverized concrete from the launch site.
An investigation by The New York Times showed that a Starship test launch held in Boca Chica in June 2024 damaged the nests of protected bird species. Reports from the Coastal Bend Bays & Estuaries Program showed that the damages were caused by concrete and rock fragments hurled from the launch site. Boca Chia is a vital habitat for these birds.
It is worth noting that the area where SpaceX operates its launches is a sensitive coastal ecosystem with valuable wildlife habitats. Reports showed that there were at least 19 incidents since 2019 in which SpaceX launch operations caused fires, leaks, and explosions. Recent operations have also raised concerns about the dumping of wastewater in natural bodies of water.
There are also specific issues concerning rockets and vehicles. Italian physicists Carmen Pardini and Luciano Anselmo investigated the casualty expectancy of uncontrolled re-entry of large space objects entering the Earth between 2010 and 2022. Findings showed that rocket stages have 84 percent and some spacecraft have 18 percent casualty expectancies.
Failed launches often result in the scattering of debris over a wide area and the release of large quantities of unused fuel containing kerosene or methane. These can contaminate the environment, endanger wildlife and ecosystems, and damage properties. Even successful launches can contribute to either debris reentries or pose risk to satellites in orbit and future launches.
FURTHER READINGS AND REFERENCES
- Ferreira, J. P., Huang, Z., Nomura, K., and Wang, J. 2024. “Potential Ozone Depletion From Satellite Demise During Atmospheric Reentry in the Era of Mega‐Constellations.” In Geophysical Research Letters. 51(11). American Geophysical Union. DOI: 1029/2024gl109280
- Jain, A. K., Eastham, S. D., and Hastings, D. 2023. Future of Satellite Reentry and Earth’s Atmosphere: the Lifetime and Direct Radiative Forcing of Space Debris Reentry Alumina. Authorea. DOI: 22541/essoar.170110669.90121203/v1
- Lipton, E. 7 July 2024. “Wildlife Protection Take a Back Seat to SpaceX’s Ambitions.” The New York Times. Available online
- Pardini, C. and Anselmo, L. 2024. “The Risk of Casualties from the Uncontrolled Re-entry of Spacecraft and Orbital Stages. In Journal of Space Safety Engineering. 11(2): 181-191. Elsevier BV. DOI: 1016/j.jsse.2024.02.002
- Pultarova, T. 21 March 2024. “How Environmentally Friendly is SpaceX’s Starship?” Space. Available online
- S. Public Interest Research Groups. 2024. “New Report Highlights SpaceX’s Skyrocketing Pollution Problem.” U.S. PIRG. Available online
- Voigt, C., Schumann, U., Graf, K., and Gottschaldt, K. D. 2013. “Impact of Rocket Exhaust Plumes on Atmospheric Composition and Climate ― An Overview.” In Progress in Propulsion Physics. 657–670. EDP Sciences. DOI: 1051/eucass/201304657