A Japanese startup named Astroscale has unveiled an ambitious project to build a ground-based laser system that can vaporize space debris orbiting the Earth using nuclear fusion energy. If successful, this revolutionary technology could provide a cost-effective and environmentally sustainable solution to the growing threat posed by space junk.
The Threat of Space Debris
Over the past 60 years of space activity, satellites, rockets and other human-made objects have accumulated in Earth’s orbit, posing an increasing hazard to operational spacecraft. According to NASA, there are currently over 128 million pieces of debris smaller than 1 cm, 900,000 pieces between 1 and 10 cm, and over 34,000 pieces larger than 10 cm orbiting the planet. Even tiny pieces of debris can inflict major damage by traveling at extremely high velocities.
The problem continues to worsen as collisions between objects generate more fragments, setting off a chain reaction of destruction known as the Kessler syndrome. In 2021 alone, there were nearly 600 break-up events in space. Without remediation, experts warn that key orbital regions could become unusable in just a few decades. This would cut off access to valuable services that satellites provide, from GPS navigation to climate monitoring and banking transactions.
| Year | Number of Cataloged Objects in Earth Orbit |
|---|---|
| 1957 | 0 |
| 2022 | >1 million (as per NASA) |
Table showing growth of cataloged space debris over time
Ground-Based Laser Removal Concept
Astroscale’s solution involves building an array of high-powered lasers that can be focused on pieces of space junk from a ground station. The extreme energy delivered by the lasers would instantly vaporize debris, eliminating the hazard. By not requiring rockets or spacecraft, this method promises to be much cheaper and cleaner than existing proposals.
The founder and CEO of Astroscale, Nobu Okada, says inspiration for the technology came from his background working on nuclear fusion research. Fusion energy offers practically limitless clean power by replicating the process that powers the Sun. While fusion reactors remain experimental, the laser systems used to initiate fusion reactions are well understood.
By adapting these cutting-edge lasers for space debris removal, Astroscale aims to turn one of space industry’s biggest problems into a business opportunity. The company has raised $191 million to date from private investors to develop their concept.
Technical Details
According to Astroscale’s white paper, the laser arrays would be powered by solar-powered hydrogen fluoride (HF) lasers operating at a mid-infrared wavelength of 2.7 to 2.9 μm. HF lasers offer an ideal combination of high beam quality and continuous firing capability for maximized range and debris destruction efficiency.
The laser beams would be directed using adaptive optics telescopes with wavefront sensing to compensate for atmospheric distortion. Precise targeting would be enabled by integrating data from existing space debris tracking sensors in the Space Surveillance Network.
To generate sufficient intensity when focused on orbiting objects up to 2000 km away, the system requires fusion-scale laser infrastructure. Astroscale’s design is centered around four high-repetition rate petawatt-class lasers, delivering pulses with over 1000 trillion watts of peak power.
Heating effects from ablation of debris fragments should not pose issues according to simulations. But to evaluate environmental impacts, the company is consulting with atmospheric scientists and plans to construct its first facility on uninhabited Arctic land.
Project Timeline
If everything goes to schedule, Astroscale aims to finish constructing the laser array by 2028. After testing, they hope to start providing commercial debris removal services in 2030.
The initial deployment would involve just a single ground site with limited capacity, but Okada envisions an eventual network of stations around the world for complete global coverage. With sufficient investment to scale up operations, the company projects being able to eliminate the majority of dangerous centimeter-sized debris within 7 years.
Expert Reactions
Astroscale’s concept has generated buzz within space industry circles, but experts are cautious about the daunting technical barriers. Professor Akari Goto from Kyoto University commends the pioneering approach but notes there are “many unanswered questions regarding operations”.
Key challenges include:
- Achieving sufficient beam intensity after atmospheric losses
- Precision tracking of small debris pieces in chaotic orbits
- Mitigating space weather impacts on beam quality
Harvard astrophysicist Dr. Hideko Suzuki further points out the project hinges on the immense costs and engineering difficulties building never-before-seen laser arrays running on nuclear fusion.
“It reminds me of proposals for solar power satellites in the 1970s that failed to get off the ground,” she said. While optimistic about applications in the more distant future, Suzuki believes cleaning up space will continue relying on post-mission disposal and regular debris removal missions for now.
Others argue that given the scale of investment motivating companies like Astroscale, ground-based lasers could feasibly provide a flexible and cost-efficient debris mitigation capability within this decade.
With active removal a widely-accepted necessity for controlling debris growth, laser ablation systems currently offer the only means to match the increasing launch rate for large satellite constellations.
Looking Ahead
The runaway space debris problem is now at a critical juncture, with Astroscale’s laser array representing one of the most ambitious solutions under development.
If the remaining technical obstacles can be overcome, ground-based lasers could eliminate dangerous debris efficiently without adding more objects to orbit. This would help safeguard satellites vital to the global economy and national security.
However, fully demonstrated systems are still years away at least. In the meantime, mitigating debris production and working on internationally-supported remediation policies remains crucial.
With the number of satellites estimated to grow from 4,000 today to over 100,000 by 2030, ensuring the long-term sustainability of space has never been more important. Japan’s groundbreaking laser debris removal program marks a pivotal step towards this goal that the world will be watching closely.
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