Space Debris: Impact On Other Devices?

Space pollution, also known as space junk, space debris, space waste, space trash, space garbage, or cosmic debris, is a pressing issue that poses significant risks to both space exploration and the planet. It encompasses defunct human-made objects in space, particularly in Earth orbit, that no longer serve a useful function. These include derelict spacecraft, mission-related debris, and fragmentation debris from the breakup of rocket bodies and spacecraft. The accumulation of space junk increases the chances of collisions with functioning satellites, endangering future missions and terrestrial communications.

Space junk travels at incredibly high speeds, often exceeding 22,000 kilometres per hour, turning these objects into dangerous projectiles. The sheer number of these objects, coupled with their velocity, makes the risk of causing severe damage to active spacecraft considerable. Collisions can generate thousands of new pieces of space debris, as evidenced by the 2009 crash between the inactive Russian satellite Cosmos 2251 and the American communication satellite Iridium 33, which resulted in approximately 2,000 large pieces of debris and thousands of smaller fragments.

The impact of space pollution extends beyond just satellites. Larger debris can occasionally impact Earth, and certain types of space junk, such as old fuel tanks containing toxic residue, can have detrimental effects on the environment. Additionally, space debris can release various chemicals into the atmosphere, contributing to ozone layer depletion and global warming.

Addressing the issue of space pollution is crucial to ensure the safety of future space missions and mitigate potential environmental consequences. Efforts to tackle space junk include active debris removal (ADR) technologies, such as using nets, lasers, or robotic arms to capture and remove defunct satellites. Additionally, the development of self-removing or self-destructing satellites and the implementation of 25-year rules for deorbiting are also being explored.

Space debris and the risk of collision

Space debris is defined by NASA as "any man-made object in orbit around the Earth which no longer serves a useful function". These objects range from minuscule flecks of paint to massive chunks of metal. As of August 2021, the European Space Agency (ESA) reports tracking approximately 29,210 pieces of debris regularly, with the actual number likely being much higher. There are an estimated 128 million objects between 1mm and 1cm in size, 900,000 objects between 1cm and 10cm, and 34,000 objects larger than 10cm.

The sheer number of these objects in orbit, coupled with their potential to slam into other objects at speeds of up to 28,000-25,000 kilometres per hour, poses a significant risk of collision. Each piece of debris becomes an obstacle in the orbital "highway", making it increasingly difficult for functional satellites to avoid collisions. The danger is not just theoretical; in 2009, a collision between a defunct satellite and an active communications satellite created thousands of pieces of debris that still orbit the Earth today.

The accumulation of space junk has catastrophic consequences for future space exploration and terrestrial communications. Each collision creates millions of pieces of shrapnel, which can then collide with other debris or satellites, leading to a chain reaction that renders our orbit too dense with shrapnel to be usable. This would result in the destruction of existing space infrastructure and make future space activities impossible.

The problem is particularly acute in low Earth orbit, where many satellites, such as the International Space Station (ISS) and NASA's Earth Observing Fleet System, operate. The ISS has had to perform 29 debris collision avoidance manoeuvres as of 2020.

The risk of collision is not just confined to space exploration. Some space junk in low Earth orbit will gradually lose altitude and burn up in the Earth's atmosphere, but larger debris can impact the Earth and have detrimental effects on the environment. For example, debris from Russian Proton rockets launched from the Baikonur cosmodrome in Kazakhstan has littered the Altai region of eastern Siberia, including highly toxic fuel residue that is harmful to plants and animals.

To mitigate the risk of collision, many satellites and the ISS are equipped with Whipple Shields, an outer shell that protects the object from a potential collision. Other strategies include orbit changes, self-destruction of satellites, passivisation (removal of internal energy at the end of a satellite's life), and the reuse of rockets.

The impact of space debris on the ozone layer

Space debris is any piece of human-made debris left in space, including inactive satellites, rocket parts, and mission-related objects like dropped tools. The accumulation of space debris is a growing problem, with approximately 900,000 objects over one centimetre in size orbiting the Earth with no use. This debris travels at speeds of over 28,000 kilometres per hour, posing a collision risk to functioning satellites and spacecraft.

Secondly, the composition of space debris can also impact the ozone layer. Satellites are mostly made of aluminium, which burns into reflective aluminium oxide or alumina upon re-entry. Alumina is a geoengineering experiment that can alter Earth's climate by scattering more sunlight and increasing the planet's albedo. Additionally, alumina can chemically react with ozone, depleting the protective layer that absorbs the sun's harmful UV rays. The risk of ozone depletion is further heightened by the presence of hydrogen chloride and alumina in solid rocket fuels, which are deposited directly into the stratosphere during rocket launches.

While the effects of space debris on the ozone layer are not yet fully understood, researchers warn that the expected increase in space travel and the lack of regulation around rocket launches and space debris could undo the efforts to repair the ozone layer. Without the international Montreal Protocol, which phased out ozone-depleting chlorofluorocarbons (CFCs), it is estimated that two-thirds of the ozone layer would have been destroyed by 2065. Similarly, without coordinated action to address the impact of space debris, the hole in the ozone layer may widen, increasing the amount of harmful UV radiation reaching Earth.

The effect of space debris on the environment

Space debris is a growing problem that poses a threat to the environment and humankind's future in space exploration. Since the beginning of the space era in 1957, thousands of rockets, spaceships, and satellites have been launched into space, and many of them have been left drifting in orbit. This space junk moves at incredibly high speeds, turning even small objects like paint flecks into dangerous projectiles.

The accumulation of space debris increases the risk of collisions with functioning satellites, which can cause serious damage and generate thousands of pieces of space trash. For example, in 2009, a collision between two satellites resulted in approximately 2,000 large pieces of debris and thousands of smaller pieces entering Earth's atmosphere. These pieces of debris can stay in orbit for decades or even centuries, posing a long-term threat to other satellites and spacecraft.

The effects of space debris are not just limited to the risk of collisions. Some of the debris contains toxic or radioactive materials that can have detrimental effects on the environment if they fall back to Earth. For instance, debris from Russian Proton rockets contains highly toxic fuel residue, unsymmetrical dimethylhydrazine (UDMH), which is harmful to plants and animals and has been linked to cancer cases in the affected areas.

Additionally, space debris can impact Earth's atmosphere and contribute to ozone depletion. Studies have shown that objects re-entering the atmosphere can create shock waves that produce nitric oxide, a known cause of ozone depletion. The metal alloys and composite materials used in spacecraft and rocket motors can also melt during re-entry, forming chemicals that react with and consume ozone.

To address the issue of space debris, several solutions have been proposed, including:

• Orbit changes: Launching satellites into elliptical orbits that will eventually cause them to break up in the Earth's atmosphere.
• Self-destruction: Programming satellites to leave their orbit and eliminate themselves when they come into contact with the atmosphere at the end of their useful life.
• Passivisation: Removing internal energy from vehicles and rocket stages at the end of their useful life to reduce the risk of explosions.
• Reuse: Using reusable rockets that return to Earth intact, such as those used by SpaceX.
• Laser technology: Using powerful lasers to vaporise the surface of debris, causing them to stop and fall.
• Removal of large pieces of debris: Using instruments like harpoons and lasers to remove large pieces of space junk.
• Self-removing satellites: Developing satellites that can remove themselves from orbit at the end of their useful life.
• Coating satellites in polymeric foam: Coating satellites with a material that allows them to descend into the Earth's atmosphere and burn up.

The cost of space debris

Space debris, or 'space junk', refers to any man-made objects in orbit that no longer serve a function. This includes everything from paint flecks to defunct satellites. The accumulation of space debris is a growing problem, with the number of satellites in orbit set to increase with the launch of 'mega-constellations' for satellite broadband. This will increase the risk of collisions and the creation of more space debris.

The Economic Cost of Space Debris

The Organisation for Economic Co-operation and Development (OECD) has outlined the dangers of space debris, and what can be done to address the problem. According to the OECD, the cost of space debris protection and mitigation measures is already high for satellite operators. However, the main risks and costs lie in the future if debris generation is left unchecked, rendering certain orbits unusable for human activity.

Protecting satellites from space debris is expensive, and includes design measures, surveillance, tracking, and sometimes even replacing missions. For satellites in geostationary orbit, these costs amount to an estimated 5-10% of total mission costs, which could be hundreds of millions of dollars. In low Earth orbits, the relative costs per mission could be even higher.

The socio-economic impacts of the Kessler syndrome (where collisions cascade, leading to more and more self-generating collisions) would be severe. Important space applications could be lost, and the inability to use certain orbits would have wide-reaching and significant consequences.

The Environmental Cost of Space Debris

Space debris poses a threat to future space exploration, with the risk of causing serious damage to functioning spacecraft. A single collision can generate thousands of particles of space trash, which can then go on to cause further collisions. For example, in 2009, a collision between two satellites resulted in approximately 2,000 pieces of debris at least 10cm in diameter, and thousands more smaller pieces, entering the Earth's atmosphere.

A proportion of the space junk in low Earth orbit will gradually lose altitude and burn up in the Earth's atmosphere. However, larger debris can occasionally impact the Earth, causing detrimental effects on the environment. For example, debris from Russian Proton rockets launched from the Baikonur cosmodrome in Kazakhstan includes old fuel tanks containing highly toxic and carcinogenic fuel residue. While efforts are made to contain fallout from launches, it is extremely difficult to achieve completely.

The challenge of removing space debris

Space debris is a pressing issue that poses a significant threat to vital technology orbiting Earth and future space exploration endeavours. The accumulation of defunct satellites, rocket fragments, mission-related objects, and even minute particles like flecks of paint, pose a grave risk to operational spacecraft. The challenge of removing this space debris is complex and multifaceted. Here are some key considerations regarding the challenge of space debris removal:

• Urgent Need for Action: The ever-growing amount of space debris endangers both terrestrial telecommunications and ongoing space missions. It is crucial to address this issue promptly to mitigate the risk of collisions and ensure the safety of functioning satellites.
• Size and Speed of Debris: Space debris comes in various sizes, ranging from tiny paint flecks to large inactive satellites. Even small fragments can cause significant damage due to their incredibly high speeds, often exceeding 28,000 kilometres per hour. This speed turns these objects into dangerous projectiles that can inflict severe damage on impact.
• Tracking and Detection: While larger objects are routinely tracked by organisations like the US Space Surveillance Network, smaller debris, such as objects below 1 cm in size, are more challenging to detect and track. This limitation hinders our ability to monitor and manage the full extent of space debris.
• Collision Risk and Consequences: The high density of objects in low Earth orbit (LEO) increases the likelihood of collisions. These collisions can generate thousands of new debris particles, as evidenced by the 2009 collision between the Iridium 33 and Cosmos 2251 satellites, which resulted in a substantial increase in space debris. Such events heighten the risk to active satellites and spacecraft, potentially rendering some orbits unusable for long-term operations.
• Legal and Economic Challenges: There is currently no international treaty specifically addressing space debris. While voluntary guidelines and national regulatory attempts exist, the lack of binding international regulations hinders comprehensive action. Additionally, there are economic challenges, as the cost of debris removal often falls on all users of space technology rather than the entities responsible for the debris.
• Technological Solutions: Various technological approaches have been proposed and tested to remove space debris. These include the use of harpoons, lasers, robotic arms, nets, and even magnetic docking systems to capture and remove defunct satellites. However, many of these methods are still in the experimental stage or face challenges such as high costs and legal questions regarding ownership of the debris.
• Preventative Measures: To mitigate future accumulation, preventative measures are crucial. This includes passivisation of satellites, self-destruct mechanisms, and the use of reusable rockets that can return to Earth intact. Additionally, the adoption of "one-up, one-down" launch licenses, where launchers remove a derelict satellite for each new one put into orbit, could help address the issue.
• International Cooperation: Addressing the space debris problem requires international collaboration and data sharing. The establishment of an international centre for exchanging information and the promotion of polycentric governance, as suggested by scholars, could help improve the management of this global issue.
• Private Sector Involvement: With the increasing commercialisation of space activities, the participation of private actors is essential. Private companies, such as Astroscale and Privateer Space, have shown interest in space debris removal and monitoring. However, their involvement needs to be more widespread and integrated into the decision-making processes to effectively tackle the issue.

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