Exploring Emission Caps and Tradable Permits for Space Launch Segment: Launching Towards Sustainability

With the rising frequency of space launches, due to decreasing cost per kg, reusable technology, satellite connectivity and data demands, concerns about the environmental impact of the Space Launch Segment (SLS) are escalating. This research article examines Emission Caps and Tradable Permits (EC-TPs) as a potential market-based instrument to curb Space Launch emissions. In this context, we thoroughly examine the environmental impact of SLS and the benefits, challenges, present situation, and prospects for EC-TPs.

Abstract

The space industry has experienced significant growth in recent years, driven by advancements in technology, policy reforms and an increasing demand for satellite services resulting in the rising frequency of space launches. However, this growth has also raised concerns about the industry’s environmental impact, particularly regarding emissions from space launches. This research article explores the feasibility and potential benefits of implementing emission caps and tradable permits as a regulatory framework for mitigating the environmental impact of the space launch segment. We comprehensively review the benefits, challenges, current status, and future outlook of EC-TPs in this context, drawing upon existing research and policy discussions.

Keywords: Space Launch, ESG, Sustainability, Regulations, Emission Caps, Climate Action, Cap-and-Trade

Introduction

Space Launch vehicles emit a range of pollutants, including black carbon, nitrogen oxides, etc. contributing significantly to climate change and stratospheric ozone depletion. Emission caps and tradable permits offer a promising regulatory approach for mitigating the environmental impact of space launches. Emission Cap and Trade Systems (EC-TPs) are market-based instruments used to regulate and reduce emissions of pollutants, typically greenhouse gases like CO2. While primarily used for greenhouse gas emissions, the EC-TP framework can be adapted to regulate emissions of other pollutants in various sectors.

Understanding Emission Caps and Tradable Permits and Regulation

Capping Emissions: A pre-determined cap, representing the acceptable total emission level for a specific timeframe, is established. This cap aligns with environmental sustainability goals and considers industry growth projections.

Permit Allocation: Dividing the capped emissions into tradable permits, each representing permission to emit a specific amount of pollutant.

Market Mechanism: Companies with efficient, low-emission technologies emit less, creating surplus permits they can sell to providers struggling to meet their allocation. This creates a financial incentive for cleaner technologies and operational practices.

To address the environmental impact of space launches more effectively, we propose the implementation of emission caps and tradable permits. Under this framework, regulatory authorities would set a cap on the total amount of emissions allowed from space launches, based on the industry’s emissions targets and environmental objectives. Companies would then be required to obtain tradable permits for their emissions, with each permit allowing the emission of a certain amount of pollutants.

Additionally, we analyze briefly the specific challenges associated with measuring and verifying emissions at different phases of the launch process: Pre-Launch, During Launch, and Post-Launch/Re-entry.

Current Status and Recent Studies on Space Launch Segment Emissions and Regulations

Current State and Future Projections of Emissions from Space Launches

A minor but growing portion of the background stratospheric aerosol population is accounted for by aerosol emissions from spaceflight operations.

• Alumina is released into the atmosphere by a number of solid rocket fuels, including the ones used by the Ariane 5.
• Rocket-grade kerosene is used as fuel in SpaceX’s Falcon 9, the most commonly launched rocket in the world today, which releases Black Carbon upon combustion. Kerosene is also used in Soyuz rockets.
• Water vapour is released by rockets powered by hydrogen, such as NASA’s SLS.
• A common fuel option for the next generation of heavy-lift rockets, such as Starship, is methane. Methane is a potent greenhouse gas in and of itself, but when it burns, it largely releases CO2 and water.

Trajectory of a typical launch vehicle through atmospheric layers during the ascent phase and the atmospheric reentry, with corresponding environmental impacts. [Source: Space sustainability isn’t just about space debris: On the atmospheric impact of space launches]

Black Carbon (BC) emitted from solid and hypergolic fuels contributes to stratospheric warming. Research by [J.A. Dallas et al., 2020] suggests a potential increase in BC emissions as launch rates rise. Black carbon from launches can trap heat in the upper atmosphere, potentially leading to Stratospheric warming and impacting global climate patterns [M. Ross et al., 2010]. Alumina (Al2O3) particles are released from solid fuels, potentially contributing to ozone depletion. Gaseous chlorine from solid fuels and kerosene are examples of additional pollutants [J.A. Dallas et al., 2020]. Because they directly inject pollutants into every stratum of the atmosphere, rockets are unlike any other manmade source.

Water vapour (H2O) and nitrogen oxides (NOx ≡ NO + NO2) are common combustion emissions shared by all propellants. According to several studies [Johnston, 1971; Ross et al., 2009; Lee et al., 2010], superheated air in the engine and exhaust plume produces NOx, which catalytically breaks down O3. Thermal NOx is also released upon re-entry into the mesosphere by crewed and reusable rockets, historical space debris, and abandoned rocket components [Larson et al., 2016].

While not currently a significant concern, some studies by the US National Oceanic and Atmospheric Administration (NOAA) suggest potential risks of Ozone layer depletion in the future if launch rates and emissions increase significantly.

Nearly all of these released contaminants cause heterogeneous chlorine (Cl)-activated O3 loss on aerosol or cloud surfaces, or they deplete stratospheric O3 through gas-phase interactions [Ross et al., 2009]. An order of magnitude greater than an equal quantity of stratospheric sulfate aerosols, Cl depletes O3 and Al2O3 accelerates Cl-activated O3 loss [Ryan et al., 2022]. According to [Kirk-Davidoff et al., 1999], the direct injection of water into the stratosphere has the potential to increase O3 loss through gas-phase interactions or by fostering the development of polar stratospheric clouds (PSCs).

The growing space industry is expected to lead to a significant rise in launch activity, potentially amplifying the environmental impact. Research on the long-term consequences of rocket emissions is still ongoing, and a more comprehensive understanding is needed to establish accurate projections and mitigation strategies.

Source: This data is based on national registers of launches submitted to the UN by participating nations. According to UN estimates, the data captures around 88% of all objects launched.

According to a research study by [C. Maloney et al., 2022] at the NOAA, as of right now, an estimated 1,000 tons of exhaust from rocket soot are released each year. The researchers issue a warning, noting that little is known about the precise soot emissions from the many hydrocarbon-fueled engines that are in use worldwide. The scientists discovered that this degree of activity would raise annual temperatures in the stratosphere by 0.5 to 2°C, or roughly 1–4°Farenheit. This would alter the patterns of global circulation by weakening the stratospheric overturning circulation and slowing the subtropical jet streams by up to 3.5%.

Source: https://www.sdo.esoc.esa.int/environment_report/Space_Environment_Report_latest.pdf

A different, reusable method of launching satellites into space that avoids the effects of black carbon, alumina, and chlorine emissions linked to current conventional technology by using “cleaner” hydrogen-fueled rockets. However, another study conducted at NOAA in 2017 looked at the climate reaction to water vapour emissions, [Larson et al., 2016] stated that rockets powered by liquid hydrogen and oxygen (O2) produce H2 and HOX in addition to H2O in their plume, using an H2-rich mixture instead of a stoichiometric ratio for increased force. A catalytic O3 destruction mechanism is possible with HOX enhancements [Crutzen, 1969].

According to a study [Ryan et al., 2022] led by UCL, the University of Cambridge, and the Massachusetts Institute of Technology (MIT), the space tourism industry may have a greater climate impact if left unregulated than the aviation industry and undo repairs to the protective ozone layer. One of the most effective international environmental policy initiatives is the worldwide ban on compounds that destroy the ozone layer, which was adopted in 1987 by the Montreal Protocol. The study used a 3D model to explore the impact of projected space tourism scenarios based on the recent billionaire space race as well as the impact of rocket launches and re-entry in 2019. Their study shows that after 3 years of space tourism emissions, the greatest change in O3 levels in the upper stratosphere of the northern hemisphere is 3–4 ppbv higher than after 10 years of continuous modern launch and reentry heating emissions.

Source: Impact of Rocket Launch and Space Debris Air Pollutant Emissions on Stratospheric Ozone and Global Climate

The upper stratosphere is the only region of the atmosphere that has seen significant ozone recovery since the Montreal Protocol, yet it is also the region that will be most negatively impacted by rocket emissions. The effectiveness of the Montreal Protocol is threatened by upper stratospheric Arctic ozone loss resulting from the launch of chlorine and re-entry nitrogen oxide emissions.

Existing Regulatory Approaches

While there are currently no comprehensive, international regulations specifically aimed at reducing emissions from the space launch industry, there are several existing frameworks and initiatives that indirectly address this issue:

International Space Treaties:

• The Outer Space Treaty (1967): This foundational treaty establishes general principles for the peaceful exploration and use of outer space. While not directly addressing emissions, it emphasizes the responsibility of signatories to avoid harmful contamination of celestial bodies and to conduct space activities in a manner that avoids causing harm to the Earth’s environment.
• The Liability Convention (1972): This convention establishes international liability for damage caused by space objects, potentially motivating launch providers to minimize potential environmental risks associated with launches.

Global Agreements:

• The Montreal Protocol on Substances That Deplete the Ozone Layer (1987): This highly successful agreement demonstrates the effectiveness of international cooperation in addressing global environmental challenges. It serves as a model for potential future regulations and highlights the importance of scientific consensus and technological innovation in finding solutions.
• The Paris Agreement (2015): While primarily focused on mitigating climate change through greenhouse gas reduction, the Paris Agreement emphasizes the importance of transitioning to low-emission and climate-resilient development pathways. This principle could be extended to the space launch industry, encouraging the adoption of cleaner technologies and practices.

National Regulations:

Many countries have national regulations governing the launch and operation of spacecraft, often focusing on public safety and preventing debris generation. Some regulations may indirectly touch upon emissions by requiring environmental impact assessments or adherence to specific launch site emission standards. However, these regulations typically lack a dedicated focus on emissions reduction from the launch vehicles themselves.

For instance, in the United States, the National Environmental Policy Act (NEPA) governs and mandates that all government agencies take the environmental impact of the activities they permit into account. This means that lanches have regulatory implications for the environment. For the space industry, the FAA has the authority to approve the construction of spaceports and grant launch permits; hence, the FAA is in charge of carrying out NEPA studies for satellite reentry and rocket launches. Additionally, NASA created an Environmental Impact Statement (FEIS) for the Mars 2020 mission in compliance with NEPA, and it identified three alternative options for the places that could be impacted, including parts of the global environment and the areas on or near the launch site.

Emerging Initiatives:

• The International Civil Aviation Organization (ICAO) Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA): This scheme, while primarily targeting the aviation sector, sets a precedent for market-based measures to address emissions from transportation activities. It could potentially serve as a model for future initiatives addressing emissions from space launches.
• The Space Sustainability Rating System (SSRS): The SSR concept was developed by the World Economic Forum’s Global Future Council on Space Technologies, this voluntary rating system assesses and promotes the sustainability practices of space actors, including considerations for emissions reduction. Developed by a consortium involving the European Space Agency, MIT, BryceTech and the University of Texas at Austin. eSpace — EPFL Space Center has been selected in 2021 to drive implementation.

Additional Resources:

• Raju, Niveditha. The Regulation of Rocket Emissions. McGill University (Canada) ProQuest Dissertations Publishing, 2020. 28267020. https://www.proquest.com/openview/919d2fb5b3cf949be2f53d0b6a844c20/1?pq-origsite=gscholar&cbl=18750&diss=y
• Elwyn Sirieys. Environmental Impact of Space Launches and Societal Response. 2022. MIT. https://dspace.mit.edu/bitstream/handle/1721.1/144846/Sirieys-elwyn-MS-AeroAstro-2022-thesis.pdf?sequence=1&isAllowed=y
• M. Ross, J. Vedda. The Policy and Science of Rocket Emissions. 2018. The Aerospace Corporation. https://aerospace.org/sites/default/files/2018-05/RocketEmissions_0.pdf

Benefits of EC-TPs for SLS Emissions Regulation:

Cost-Effectiveness: Unlike traditional command-and-control regulations that prescribe specific emission reduction methods, EC-TPs allow companies to choose the most cost-efficient strategies, fostering innovation and competition in developing cleaner technologies.

Flexibility: The system can adapt to changing circumstances by dynamically adjusting the cap over time or creating different permit types for specific emissions categories, catering to the evolving nature of the launch industry.

Incentivizing Innovation: The financial pressure to acquire additional permits drives companies to invest in research and development of cleaner propulsion systems, greener propellants, and launch optimization techniques, accelerating the transition towards a more sustainable spacefaring future.

Challenges and Considerations for Implementing EC-TPs for SLS, Including Emerging Players and Unequal Capabilities

Implementing emission caps and tradable permits for the space launch segment would pose several challenges. One challenge is determining the appropriate level of the emission cap, taking into account the industry’s growth projections and environmental objectives.

Market Participation: Emerging private sector companies and countries with less launching frequency or capabilities may face challenges in participating in the tradable permit market. They may have limited resources to acquire permits or invest in emission reduction measures, which could hinder their ability to compete with larger companies.

Design Complexity

• Equity and Fairness: There is a risk that the regulatory framework could disproportionately impact emerging private sector companies and countries with less launching frequency or capabilities, potentially leading to inequities in the market for emission permits.
• Fairness for Emerging Players: Ensuring fair participation for emerging private space companies with limited resources and lower launch frequencies compared to established players. This may involve considerations like:
• Differentiated Permit Allocation: Exploring methods for initial permit allocation that acknowledge the different realities of established and emerging players, fostering participation without overwhelming newcomers.
• Financial and Technical Assistance: Providing emerging players with access to financial and technical assistance to help them adopt cleaner technologies and navigate the EC-TP system effectively.

Data & Monitoring: Accurately measuring and verifying emissions from various launch systems necessitates robust data collection and monitoring infrastructure, including standardized emission measurement protocols and independent verification mechanisms. This can be particularly challenging for countries with less developed infrastructure.

Capacity Building: For new private businesses and nations with fewer launch frequencies or capabilities, developing the capacity to precisely monitor and report emissions might be difficult. Demonstrating compliance with regulatory obligations may become challenging as a result.

International Cooperation: The success of EC-TPs hinges on global collaboration. Establishing a level playing field through international agreements and preventing “permit leakage” (companies relocating to circumvent regulations) are crucial aspects for effective implementation, requiring:

Inclusive Policy Development: Collaborative policy development involving both established and emerging spacefaring nations to ensure the system addresses the needs and concerns of all participants.

Challenges for Implementing EC-TPs and Measuring Emissions Across Launch Phases

Measuring and verifying emissions accurately across the various phases of the launch process pose distinct challenges:

Pre-Launch:

• Emissions from ground testing of engines and other launch vehicle components need to be incorporated into the EC-TPs system.
• Emerging Mobile launch stands present additional challenges in terms of emission capture and measurement.
• Standardizing emission factors for different materials and processes used in launch vehicle and spacecraft production becomes crucial for accurate accounting.

During Launch:

• Real-time monitoring of emissions during the launch ascent is essential, requiring the development and deployment of robust onboard or remote measurement systems.
• Data transmission and verification from high altitudes can be challenging and require secure and reliable communication infrastructure.

Post-Launch/Re-entry:

• Tracking released propellants and spacecraft debris in high orbital environments necessitates advanced space surveillance and tracking systems.
• Re-entry and potential atmospheric breakdown of spacecraft components require monitoring and emission accounting for uncontrolled re-entries.

As launch frequency continues to rise, mitigating these environmental consequences becomes an urgent imperative.

Lessons and Effectiveness of Existing EC-TPs Systems in Other Sectors

While not currently employed for regulating SLVs, EC-TPs have been successfully implemented in other sectors, offering valuable lessons for potential application in the space launch industry:

The European Union Emissions Trading System (EU ETS): This system, launched in 2005, regulates CO2 emissions from power plants and heavy industries in the EU. It highlights the:

• Importance of robust data collection and verification: Ensuring accurate and transparent emission reporting is vital for system effectiveness.
• Need for continuous monitoring and adjustment: The EU ETS has undergone modifications over time to address evolving market conditions and ensure the cap remains effective in achieving environmental goals.

The Regional Greenhouse Gas Initiative (RGGI) in the United States: This program, launched in 2009, regulates CO2 emissions from power plants in nine northeastern states. RGGI demonstrates the:

• Potential for regional collaboration: Effective implementation can be achieved through collaboration among a group of nations with shared environmental goals.
• Flexibility in permit allocation: RGGI utilizes a hybrid approach, combining auctioning and free allocation of permits, to address concerns about equity and economic competitiveness.

Additional Examples:

• California Cap-and-Trade Program: This program, launched in 2012, regulates greenhouse gas emissions from a broader range of sources, including transportation fuels and industrial facilities, showcasing the potential of EC-TPs beyond the power sector.
• The Acid Rain Program (ARP) in the US: This program, in operation successfully addressed sulfur dioxide emissions from power plants, demonstrating the effectiveness of TPs in tackling specific environmental challenges.

Moving Forward: Research, Pilot Programs, and Collaborative Action

Although EC-TPs are not being used to control SLV emissions, they are becoming more and more popular as a viable policy choice. As the industry matures and its footprint expands, implementing well-designed, collaborative EC-TP systems becomes increasingly essential. Further research is crucial to explore the specific design details and potential economic impacts of EC-TPs within the context of the space launch industry. Conducting pilot programs and simulations through economic-environmental models in specific countries can provide more valuable data on the effectiveness and challenges of implementing such a system. Additionally, fostering international cooperation through dialogue, knowledge sharing, and collaborative policy development is essential for establishing a global framework for EC-TPs in the space sector.

Conclusion

EC-TPs offer a promising, yet complex, approach to regulating and reducing emissions from the space launch industry. By setting limits on emissions and creating a market for emission permits, this approach would incentivize companies to reduce their emissions cost-effectively, while ensuring that overall emissions remain within acceptable limits. However, implementing this framework would require careful planning and coordination among regulatory authorities, industry stakeholders, research agencies and other relevant parties. Further research and stakeholder engagement are needed to develop a detailed implementation plan and address potential challenges.

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