How can we make the space sector more sustainable?

28 Jul 2023

Image: © chathuporn/

With the amount of emissions and space debris this sector can cause, various initiatives are working to create a space economy that is less harmful to the environment.

With constantly rising temperatures and concerns about the future climate, sustainability has become more of a focus for multiple industries.

The space sector is no exception, with national and international initiatives striving to reduce the environmental impact that this industry has on Earth.

The global focus on space exploration is on the rise, with public and private entities preparing new missions to expand satellite networks and explore the solar system. But this increased focus could lead to a surge in pollution.

Research from the US National Oceanic and Atmospheric Administration claims roughly 1,000 tonnes of rocket soot exhaust are emitted into the atmosphere annually. This report also warned that a significant boost in this sector could damage the ozone layer.

Sustainability roadmaps and pledges

To address this issue, some countries are setting goals to reduce the environmental impact of national space endeavours. For example, Scotland launched a Space Sustainability Roadmap last year to help reduce the impacts of building, fuelling and launching satellites.

This roadmap sets out short-term goals to complete by 2025, along with medium and long-term goals to complete by 2035 and 2045.

“The recommendations in the roadmap create a unique opportunity to ensure that the sector develops sustainably with a minimum impact on both the orbital and terrestrial environment,” the sustainability roadmap states.

Global initiatives also exist to create a sustainable space economy in the future. Last month, India became the 27th nation to sign the Artemis Accords, which are a set of principles to guide space exploration cooperation among nations.

These accords include various guidelines and practices for the “sustainable and beneficial use of space for all humankind”. The partner nations of these accords are also required to show transparency by publicly describing their own space policies and plans.

“India is a responsible space power and places the highest importance on the peaceful and sustainable use of outer space,” said India’s US ambassador Taranjit Singh Sandhu.

“We are confident that the Artemis Accords will advance a rule-based approach to outer space. It also underlines our collective belief that exploration is not just the pursuit of knowledge – of knowing the unknown – but is a catalyst in advancing the betterment of humanity.”

Space Sustainability Rating

The Earth’s orbit is also getting more crowded, with more pieces of spacecraft, satellites and other debris being detected. Meanwhile, the number of active satellites is projected to rise significantly in the coming years.

There are fears that this combination could lead to Kessler Syndrome, which is a scenario where the amount of objects in space create a cascading effect – with space collisions creating more debris, which causes even more collisions.

In order to reduce this risk, a coalition of organisations has made a Space Sustainability Rating (SSR), a voluntary initiative for spacecraft operators, launch service providers and satellite manufacturers.

The focus of this rating is to encourage responsible behaviour in space by increasing the transparency on the “debris mitigation efforts” of organisations. Organisations that join the SSR will provide mission data through a questionnaire, which will be evaluated in combination with other external data.

Missions will be given a score representing their sustainability in terms of debris mitigation and alignment with international guidelines. Factors that are judged include the choice of orbit, measures taken to avoid collisions, plans to de-orbit satellites and how well these satellites can be detected from Earth.

The initiative aims to reduce the risk of collisions and space debris generation and ensure that future missions launched into Earth orbit are sustainable. The SSR was developed by the World Economic Forum, the European Space Agency, MIT Media Lab and other partners.

Sustainable space transport

New initiatives also aim to make space travel more sustainable and reduce the intense emissions these rockets create. Two space companies are developing a form of sustainable space travel for tourists, in the form of a balloon.

This mode of transport is being made by French company Stratoflight and is designed to reach the stratosphere – 35km above ground level – with four passengers and two pilots.

The vehicle will use zero-pressure balloons that are filled with green hydrogen. The company said this hydrogen will be produced at a take-off site using solar and wind energy to ensure a zero-carbon footprint. Stratoflight plans to take bookings this year, with the first flights scheduled for 2025.

The engineering company Expleo is designing the flight capsule for Stratoflight, which includes an extra-vehicular viewing platform. Stratoflight plans to let passengers step out into space from this platform in pressurised suits to view the Earth from the stratosphere.

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Leigh Mc Gowran is a journalist with Silicon Republic