15. Space Debris

Introduction

Since the launch of Sputnik in 1957, the number of satellites orbiting Earth has grown to approximately 1,400. These satellites are crucial for modern society, supporting industries such as communications, television, navigation, weather monitoring, and military reconnaissance, contributing to a global market worth over $300 billion (£233 billion). However, alongside active satellites, there are millions of pieces of space debris orbiting Earth. NASA estimates there are over 100 million pieces smaller than 1 cm, about 500,000 pieces ranging from 1–10 cm, and 21,000 larger pieces in orbit. Travelling at speeds of up to 40,000 kph, these fragments pose a significant risk to operational satellites and the International Space Station (ISS). Even a small piece of debris, such as a 1 cm paint fleck, can cause significant damage equivalent to an object weighing 250 kg travelling at 27 m/s on Earth.

The problem of space debris is compounded by Kessler Syndrome, a theoretical scenario where the density of debris in low Earth orbit becomes so high that collisions between objects generate more debris, leading to a cascade effect. This would make Earth’s orbit uninhabitable for satellites and future space exploration, endangering human space travel and threatening re-entry events on Earth.

Task

Your team has been tasked with addressing the growing threat of space debris and the potential onset of Kessler Syndrome. You are to propose a solution that either removes existing debris, prevents further debris from being generated, or mitigates the risks posed by current debris. The solution can address the entire problem or focus on a specific aspect, as it is likely that multiple solutions from different teams will be needed. Your solution must balance technological feasibility, cost, and long-term sustainability while considering the existing infrastructure in space.

Considerations

1. Technology
Your solution must account for the scale and complexity of the space debris problem. Consider the velocity, distribution, and size of the debris as well as the operating satellites and space stations. You will also need to choose appropriate materials and technologies capable of withstanding the harsh conditions of space. Your design may include methods for capturing debris, deflecting it, or reducing the chances of further collisions.

Questions to consider:

• What technologies and materials will be best suited to address the space debris problem in low Earth orbit?

• How will your solution handle the vast distances, high velocities, and varying sizes of debris?

• What engineering challenges, such as energy requirements, equipment durability, and precision, need to be solved?

2. Infrastructure
Your solution must consider how it will interact with the existing space infrastructure, including active satellites, space stations, and other objects in orbit. The deployment, operation, and potential retrieval of your proposed solution should be feasible within the current space environment. Additionally, you need to ensure that your solution will not add to the debris problem or create risks for future operations.

Questions to consider:

• How will your solution integrate with or affect existing satellites, space stations, and other orbiting objects?

• What are the logistics of launching, deploying, and operating your system in space?

• How will you prevent your solution from becoming part of the problem by generating additional debris?

3. Market Factors
The growing space industry presents a market opportunity for solutions that address space debris. Governments, private companies, and international space agencies all have vested interests in maintaining clear orbital paths. Your proposal must be competitive and cost-effective, offering good value for the investment.

Questions to consider:

• Who are the potential stakeholders or customers for your solution (e.g., governments, satellite operators, space agencies)?

• How will your solution compare to existing or developing alternatives in terms of performance and cost?

• What is the potential market size for your proposed solution, and how could it evolve with the growth of the space industry?

4. Safety, Security, and Risks
Space debris poses significant safety risks, not just to satellites but also to astronauts and future space missions. You must assess the risks involved with your proposed solution, including operational risks and potential unintended consequences. Your design must ensure safe deployment and operation without increasing the danger in space.

Questions to consider:

• What are the safety risks involved in deploying and operating your system, and how will you mitigate them?

• How will you ensure that your solution does not accidentally create more debris or cause unintended damage?

• Are there potential cybersecurity concerns related to controlling or monitoring your system in space?

5. Project Management Approach
A successful solution will require careful planning, from the research and development phase to testing, deployment, and long-term operation. Your project management approach should outline key milestones, timelines, and resource allocation. You must also consider the testing and validation process, as space systems require rigorous testing before deployment.

Questions to consider:

• What project management methodology will you use to guide the development of your solution?

• How will you allocate resources such as personnel, time, and funding throughout the project lifecycle?

• What are the critical milestones, and how will you ensure the project stays on track?

6. Costing and Feasibility
Your solution must be economically viable and offer value for money compared to competing ideas. Consider both the initial development costs and the long-term operational costs. While the budget for solving the space debris problem is substantial, your solution should still aim to be cost-effective.

Questions to consider:

• What are the estimated costs for designing, building, and deploying your solution?

• How will your system be maintained or decommissioned, and what are the associated costs?

• How does your solution compare in terms of cost-effectiveness with other proposed or existing solutions?

7. Sustainability, Ethics, Equality, Diversity, and Inclusion
Sustainability is a key consideration for space debris solutions. Your system should be durable, have a long operational life, and minimise its environmental footprint. Additionally, the ethical implications of space activities must be considered, as well as the need to ensure that space remains accessible and equitable for future generations.

Questions to consider:

• How will your solution be sustainable in terms of materials, maintenance, and long-term operation?

• What ethical concerns should be addressed, such as the responsibility for cleaning up space debris and ensuring future space access?

• How does your project promote inclusivity and equality in space exploration, ensuring that space remains accessible to all countries and communities?

Further Information

1. Paul Ratner, "How the Kessler Syndrome can end all space exploration and destroy modern life", in Big Think, Aug. 29, 2018. Available: https://bigthink.com/paul-ratner/how-the-kessler-syndrome-can-end-all-space-exploration-and-destroy-modern-life. [Accessed October 9, 2024].

2. Khan, Mohammed Vaseeq Hussain, and Efstratios L. Ntantis. "Space Debris: Overview and Mitigation Strategies." Proceedings of the 8th International Conference on Research, Technology and Education of Space, H-Space. 2024. Available:  https://www.researchgate.net/profile/Efstratios-Ntantis/publication/378802933_Space_Debris_Overview_and_mitigation_strategies/links/666af1a5a54c5f0b946463e3/Space-Debris-Overview-and-mitigation-strategies.pdf [Accessed October 9, 2024].

3. Mu, Chaoxu, et al. "Autonomous spacecraft collision avoidance with a variable number of space debris based on safe reinforcement learning." Aerospace Science and Technology 149 (2024): 109131. Available: https://www.sciencedirect.com/science/article/pii/S1270963824002645?casa_token=HnvQwArQZ5QAAAAA:ePUywTbsGSmgaiR3_iuGmaE9-ly-sZm_1v3u-qt4hrVbLMcuBbEGWUJYTbSvJNKqFqvWcNF5Kg [Accessed October 9, 2024].

4. Letizia, Francesca, et al. "Improving the knowledge of the orbital population New technical means of space debris monitoring." Acta Astronautica 223 (2024): 734-740. Available: https://www.sciencedirect.com/science/article/pii/S0094576524003461?casa_token=17jXU47e6VoAAAAA:vG8FW_dlf44ymE2yU-yEgQ6Pf7GpSRAb5PaejBrpwW2RK8j4MpTLL8Ui1uHWHmHu2cH0iAmxSA [Accessed October 9, 2024].

5. Singh, Gurpreet, et al. "Tracking an untracked space debris after an inelastic collision using physics informed neural network." Scientific Reports 14.1 (2024): 3350. Available: https://www.nature.com/articles/s41598-024-51897-9  [Accessed October 9, 2024].