The number of satellites orbiting Earth has rocketed upward in the last decade – from 200 satellites in 2013 to more than 10,000 in operation today. Once these satellites are in orbit, they share a space that is becoming increasingly crowded, and that has raised concerns about orbital sustainability.
Thankfully, advancements are being made to improve orbital sustainability with both private and public entities taking action to help remedy orbital debris.
What Does Orbital Sustainability Mean?
Orbital sustainability (or space sustainability) refers to the responsible management of space environments to ensure that future generations can also use them. The rapidly increasing number of satellites, spacecraft, and other human-made objects entering Earth's orbit has made maintaining a sustainable orbital environment a priority for governments, space agencies, and private companies.
Practices that make up orbital sustainability include reducing space debris, optimizing satellite lifespans, employing safe deorbiting solutions, and developing new technologies to clean up existing orbital debris. These efforts are crucial if mankind wants to keep using space for commercial, scientific, and exploratory purposes.
The Growing Problem of Orbital Debris
Orbital debris, also commonly called space junk, is made up of inactive satellites, spent rocket stages, discarded hardware, and fragments from collisions and explosions in space. Tens of thousands of debris pieces are currently orbiting Earth at high speeds, and even tiny objects could pose a serious risk to operational satellites and space missions.
There are a lot of uncertainties and risks associated with orbital debris. Debris smaller than 10 centimeters is not tracked by the U.S. Space Surveillance Network and therefore can’t be avoided by space operators. This unknown debris environment makes it more difficult to coordinate safe space traffic.
What Are the Dangers of Orbital Debris?
Threat to Active Satellites: Debris traveling at speeds exceeding 27,000 km/h can cause catastrophic damage to operational satellites, disrupting essential services like GPS, weather monitoring, and communications. Even a 1-cm-sized piece of debris (about the size of a U.S. penny or a button) could disable a satellite.
Collision Risks for Spacecraft: The International Space Station (ISS) and other crewed missions have had to adjust their orbits to avoid debris, adding operational complexities and fuel costs. Small debris can penetrate ISS shields, and NASA reports it has taken measures to avoid space debris 39 times since the ISS launched in 1998.
Kessler Syndrome: The rapid increase of objects in space has raised fears of a theoretical scenario called Kessler Syndrome, named after the former NASA scientist Donald Kessler. This is a hypothetical phenomenon in which space debris accumulation triggers a chain reaction of collisions, clogging Earth’s orbit with so much space junk that certain orbital regions become unusable.
Impacts on Future Missions: NASA estimates that around 100 million pieces of small debris are not currently tracked and are large enough to damage or destroy spacecraft. Growing debris clouds could make space launches riskier, increasing costs and limiting future space exploration.
How Are Businesses Approaching Orbital Sustainability?
Governmental organizations and private companies are investing in solutions to tackle the problem of space debris and improve orbital sustainability. Key strategies include:
Active Debris Removal (ADR): Companies like ClearSpace and Astroscale are developing spacecraft designed to capture and remove defunct satellites and debris. These technologies use robotic arms, harpoons, magnets or nets to deorbit debris safely.
Satellite End-of-Life Planning: Satellite manufacturers are incorporating deorbiting mechanisms into their designs to ensure that satellites either re-enter Earth’s atmosphere safely or move to designated orbits for non-operational satellites after their missions end.
Smarter Satellite Design : Innovations such as biodegradable, modular and repairable satellites are making spacecraft more sustainable. These developments allow for the possibility of in-orbit servicing and extend satellite lifespans, reducing the need for new satellite launches.
Space Traffic Management: AI-driven space junk tracking systems are being developed to monitor and predict debris movements, allowing for better collision avoidance strategies. Apple co-founder Steve Wozniak’s startup Privateer developed the app Wayfinder, which provides a near real-time visualization of satellites and debris in low Earth orbit.
International Regulations & Policies: Governments and space agencies are implementing stricter guidelines for satellite launches, orbital positioning, and deorbiting protocols to mitigate debris creation. The most prominent global efforts are by the United Nations Office for Outer Space Affairs (UNOOSA). But there is still no legally-binding treaty to help protect Earth’s orbit from the growing threat of space debris.
What Does the Future of Orbital Sustainability Look Like?
The future of orbital sustainability will be shaped by technological advancements, policy enforcement, and global cooperation between governments, space agencies and private companies. Some key trends and developments include:
Reusable Rockets and Spacecraft: Companies including SpaceX and Blue Origin are pioneering reusable launch vehicles, which reduce the number of discarded rocket stages left in orbit.
In-Orbit Servicing and Manufacturing: The European Space Agency has dedicated more than €119 million for a mission to enhance in-space refueling, repairs, and assembly of satellites. More in-orbit servicing would extend the lifespan of satellites and minimize the need to launch entirely new spacecraft.
Legal Frameworks for Space Sustainability: Organizations such as the United Nations Office for Outer Space Affairs (UNOOSA) and national space agencies are working to establish and enforce space sustainability agreements to guarantee long-term orbital usage.
Advancements in Propulsion Technology: Companies including Safran are developing satellite propulsion systems that minimize orbital debris creation, such as electric and plasma propulsion.
Increased Public and Private Sector Collaboration: Partnerships between governments, space agencies, and private space tech companies are driving innovation and responsible orbital practices as space becomes more commercialized.
The first known orbital debris was created in a 1961 fragmentation event. But only in this decade are meaningful initiatives being launched to combat space junk and keep space clean and safe. As space activity increases, orbital sustainability depends on proactive steps to keep Earth’s orbit viable for generations to come.
To learn more about efforts to design green satellites, check out this article: Sustainable Satellite Design: How Sustainability is Shaping the Future of Space