With Virgin Galactic, SpaceX, Blue Origin, Orion Span, Boeing, Space Adventures, Zero 2 Infinity and many others launching spacecraft, we are in a new era of suborbital travel beyond the horizon. A trip to suborbital space with Virgin Galactic will cost you $450,000, while Blue Origin will cost you up to $28 million. As a result of the space race that started in 1957, we have achieved a lot. Throughout our exploration journey, we have leveraged orbital missions to research the atmospheres of various planets, sounding rockets to understand our planet's atmosphere, satellites for monitoring purposes, and large telescopes to uncover the universe's enigmas. From studying our planet and solar system to venturing beyond with Voyager missions, we have reached places once only imagined. But do all these experiments and launches cost nothing to our climate? It is interesting to observe how human curiosity, on the one hand, has opened the gates to the universe and, on the other, is closing the gates to our hope of reversing the damage caused by climate change.
Image credit: @19mahima
The rockets we admire? They consume hydrocarbon fuels, emitting the same climate-damaging carbon dioxide (CO2) as cars, but in much larger quantities. This CO2 traps heat, gradually raising Earth's temperature – not the legacy we wish to leave for future space travellers! Moreover, rockets also emit black carbon, which are sooty particles lingering in the stratosphere for extended periods. These tiny troublemakers act as heat absorbers, trapping sunlight and warming the planet more efficiently than CO2. Even worse, they have the potential to disrupt the ozone layer, Our vital shield against harmful solar radiation.
For example, during a single launch, SpaceX's Falcon 9 consumes a massive 112 tonnes of refined kerosene, emitting around 336 tonnes of CO2 (Kilgore, 2022). This is comparable to an average car circling the globe nearly 70 times! The released CO2 contributes to heat retention, gradually raising the Earth's temperature - a legacy we wouldn't wish to pass on to future space travellers (“Is Space Travel Good for the Environment? No | TIME,” n.d.).
NOAA and The Aerospace Corp. collaborated to study the impact of increased black carbon emissions from kerosene-fueled rockets on Earth's stratosphere due to growing space activities and published in “the Journal of Geophysical Research Atmospheres” in 2022 (Kiest, 2022). Findings suggest risks to the ozone layer and climate from hydrocarbon-fueled space launches. Rocket emissions affect atmospheric circulation, and ozone levels, and may increase UV radiation exposure. Research emphasizes the significance of black carbon emissions from rockets and the need for further study of space industry emissions' impact on Earth's climate and ozone layer. According to the study, approximately 180 global rocket launches last year contributed around 1,000 tons of soot into the upper atmosphere annually.
Currently, space launches produce relatively low levels of greenhouse gas emissions in comparison to industries like aviation. However, the space industry is expanding rapidly, with initiatives such as Starlink planning to launch tens of thousands of satellites soon. This increase in launches has sparked worries among scientists, as even minor effects today could develop into major environmental challenges in the future.
Is there any hope for change, or will we overlook the matter until it becomes critical like other issues? The answer is no. Despite the growth of the space industry, they are conscious of their carbon footprint and have already begun making adjustments to prioritize eco-friendly practices in space travel.
There are a few examples of the efforts made by the space industry to reduce its carbon footprint.
Reusable Rockets: Reducing production and materials required by reusing rocket stages, as seen with SpaceX Falcon 9.
Biofuels: Research on cleaner-burning alternatives sourced from plants or algae, such as Astra's biofuel rockets.
Methane Rockets: Employing methane to minimize CO2 emissions in comparison to conventional fuels, like Blue Origin's methane engines.
Electric/Hybrid Propulsion: Exploring electric and hybrid systems for potential use in future spacecraft.
Emission Capture & Removal: Creating technologies to capture and store rocket emissions before atmospheric release, similar to carbon capture and storage methods.
Balancing space exploration with Earth's protection is crucial. Space offers valuable knowledge and technology, but harming Earth is not acceptable. The challenge is to explore space while being responsible stewards of our planet for the future of space exploration. By embracing a mindset of conservation and innovation, we can pave the way for a harmonious coexistence between our cosmic aspirations and our duty to safeguard our home planet.
References
Is Space Travel Good for the Environment? No | TIME [WWW Document], n.d. URL https://time.com/6273065/space-travel-climate-impact/ (accessed 4.7.24).
Kiest, K., 2022. Projected increase in space travel may damage ozone layer. NOAA Res. URL https://research.noaa.gov/2022/06/21/projected-increase-in-space-travel-may-damage-ozone-layer/ (accessed 4.7.24).