The weirdest stuff orbiting Earth - Jim Bentley and Imogen Ellen Napper

Key Concepts

• Orbital Debris
• Space Junk
• Kessler Syndrome
• Controlled Re-entry
• Servicer Satellites
• Space Tug Boats
• Laser Debris Removal

The Growing Problem of Orbital Debris

The video begins by highlighting the historical context of space litter, dating back to the Apollo 11 mission in July 1969 when Neil Armstrong and Buzz Aldrin left behind not only footprints but also discarded boots, tools, and vomit bags. This practice has continued, with examples like Suni Williams losing a camera on the ISS in 2006 and a bag of tools worth $100,000 in 2007. While many of these "accidental satellites" have short lifespans and burn up upon re-entry, others, such as SpaceX's Tesla Roadster, remain in orbit indefinitely.

Initially, this space litter was considered inconsequential. However, in today's increasingly crowded orbital environment, this debris poses a significant threat to the thousands of satellites essential for Earth's vital technologies.

Scale and Impact of Orbital Debris

• Quantity: Currently, over 131 million pieces of debris are orbiting Earth.
• Speed: This debris travels at an average speed of 10 kilometers per second.
• Size Range: Debris varies in size from that of a bus to a grain of sand.
• Hazardous Size: Approximately 1 million pieces are at least one centimeter across, which is sufficient to cause severe damage to most satellites.

The Risk of Collisions and Kessler Syndrome

Collisions between satellites and debris, or between satellites themselves, can have devastating knock-on effects. A notable example is the 2009 collision between an American communications satellite and a defunct Russian satellite, which resulted in the explosion of both into thousands of new pieces of debris.

The video explains the concept of the Kessler Syndrome, a catastrophic cascade effect where an increase in debris triggers a runaway chain reaction, potentially destroying a vast number of orbiting spacecraft.

Implications for Earth

While the probability of space shrapnel landing on Earth is low, as most debris burns up during re-entry, larger objects can survive. The SpaceX Capsule landing in an Australian field in August 2022 serves as an example. The increasing amount of space junk raises the odds of such occurrences.

Solutions to Mitigate Space Debris

The video outlines a multi-pronged approach to address the space debris problem:

1. Preventing New Debris Creation:

   • Reducing Waste from Launches: Historically, thousands of disposable rockets have been used to launch nearly 16,000 satellites since 1957, leaving behind rocket bodies, covers, cowlings, and explosive bolts. Researchers are now developing systems capable of launching over 100 satellites in a single rocket.
   • Maintaining Existing Satellites: NASA and private companies are developing servicer satellites designed to refuel, inspect, and repair existing satellites, preventing them from becoming defunct and contributing to debris.

2. Cleaning Up Existing Debris:

   • Controlled Re-entry: When a satellite reaches the end of its operational life, engineers can perform a controlled re-entry to intentionally burn it up in Earth's atmosphere. Ideally, this should happen immediately after a satellite is out of use.
   • Enforcement of Guidelines: Current guidelines outside the US permit defunct satellites to remain in orbit for up to 25 years, but this rule is poorly enforced.
   • Targeting Dangerous Debris: Researchers have identified particularly hazardous debris, suggesting efforts should prioritize their removal.
   • Technological Solutions:
     • Lasers: Proposals include using lasers, both ground-based and space-based, to nudge small debris into higher, safer orbits or into the atmosphere.
     • Space Tug Boats: Private companies are developing space tug boats to transport large debris to less dangerous orbits.

Conclusion

The video concludes by drawing a parallel between the satellites and orbital debris in space and human consumption on Earth. To continue utilizing and exploring space, humanity must improve its waste management practices, both in orbit and on Earth.