Understanding Space Debris and Removal Techniques

This article explores the fundamentals of space debris and the problems it creates. We’ll also look at various methods being developed to remove this debris.

Introduction

Satellites are indispensable tools for a wide range of applications, including communication, navigation, observation, and scientific research. They occupy various orbits, such as Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geostationary Earth Orbit (GEO).

Space debris is the unfortunate byproduct of our space activities. It originates from discarded rocket stages, defunct satellites, collisions, explosions, and other sources.

According to the European Space Agency (as of December 2020), the amount of space debris is staggering:

• Approximately 128 million debris fragments ranging from 1 mm to 1 cm in size.
• Around 900,000 fragments between 1 and 10 cm in size.
• 34,000 fragments larger than 10 cm.

What is Space Debris?

Space debris can be broadly categorized into two types: natural and artificial.

• Natural debris: This includes meteoroids and other naturally occurring objects.
• Artificial debris: This is the more pressing concern. It consists of the remnants of human-made satellites and space missions.

The amount of artificial debris is increasing rapidly as we launch hundreds of new satellites into space each year. This debris includes:

• Old, non-functional satellites
• Rocket bodies
• Disintegrated parts of satellites
• Collision fragments
• Construction materials from the International Space Station (ISS)

Space debris is found in both low-altitude Earth orbit (LEO) and high-altitude geostationary Earth orbit (GEO). It’s not just wasteful; it poses a significant threat to operational satellites and space stations. Furthermore, this debris threatens our ability to utilize valuable orbits in the future.

Space Debris Removal Techniques

Several techniques are being developed and implemented to clean up space debris. Here are a few examples:

• Bi-directional momentum ejection: This technique involves equipping operational satellites with a system to push space debris into Earth’s atmosphere, where it will burn up naturally.

• Space garbage trucks: These vehicles are designed to push debris either into Earth’s atmosphere for incineration or into a lower orbit around the Earth. Debris in low Earth orbit will eventually decay and fall back to Earth.

• Jellyfish satellites: Smaller satellites can be launched with “jellyfish-like” tentacles to grab space junk. Once captured, the satellite and debris are guided back into Earth’s atmosphere for destruction via heat and friction.

• High-powered pulsed lasers: These lasers are used to slow down the speed of debris, causing it to re-enter Earth’s atmosphere or fall into the oceans.

• Space balloons: Large balloons can be deployed to bring space junk into the atmosphere for natural burning.

• Space pods: These are used to push debris out of useful orbits and into Earth’s atmosphere.

• Other Techniques: Additional methods include launching rockets with water to create drag, recycling satellite components, and using robotic arm systems (like “sticky booms”) to capture debris.