SPACE JUNK COWBOYS
The problem of space debris from satellites and rockets is becoming increasingly pressing as human activities in space increase. Thankfully, methods for orbital recycling are being researched.
On the night of 21 August, next to the Perseids, from Saronno, in the province of Varese, at 5.21 a.m., the largest human object in space, the International Space Station (ISS), was spotted with the naked eye. Nasa has made a widget available so that one can sight this monumental structure in the night sky, consisting of pressurised modules, structural pylons, solar panels and other components that have been assembled in orbit over the course of multiple space shuttle and rocket missions launched by various countries.
Today, this space goliath, with a length of about 72.8 metres, a width of 108.5 metres (including solar panels) and a mass of about 420 tonnes, is heading towards its end of life.
According to NASA and Esa, by 2030 the ISS will be decommissioned after two decades of uninterrupted service. But its end requires meticulous planning to recover as many components as possible. When it was built, engineers certainly did not think about ISS’ end of life, nor about managing modules and components for recovery. Today, the main option is the so-called 'controlled deorbit', which involves guiding the station to a safe re-entry into the Earth's atmosphere. In this scenario, the ISS would be re-entered in a remote area of the Pacific Ocean, known as 'Point Nemo', to minimise the risk of impact with inhabited areas. However, an attempt would be made to save selected expensive components to be brought back to earth. At the moment, NASA has engaged with the Smithsonian National Air and Space Museum and other organisations to develop a preservation plan for some objects from the space station. More for commemoration than for circular economy, but they will certainly try to move as many objects as possible.
Another option is move toward outer space. The American agency has considered the possibility of moving the ISS from its current orbit to a higher orbital regime, where its lifespan could theoretically be extended, thus preserving the spacecraft for future generations. The space station currently operates at an altitude (415 km above the surface) where the Earth's atmosphere still creates resistance and requires regular re-launch to remain in orbit. Not a place where it may last
for ages, risking to crash on the ground without control.
A UNIVERSE OF WASTE
Beyond the decommissioning of the ISS, the problem of space debris from satellites and rockets is becoming increasingly pressing as human activities in space increase. With more than 34,000 objects larger than 10 cm in orbit, and hundreds of millions of smaller fragments, space debris poses a growing threat to both operational satellites and future space missions in LEO (Low Earth Orbit, with an average altitude of 800 km).
To address this problem, the scientific community and the global space industry are developing several innovative technologies for collecting and recycling space waste. These technologies are essential not only to reduce the risk of collisions, but also to promote a more sustainable use of orbital resources. And protect the Earth.
In March 2022, a family in the rural town of São Mateus do Sul, Brazil, found a 600-kilogram piece of metal shattered just 50 metres from their house. Four months later, two Australian sheep farmers found a strange black object that appeared to have lodged in a field. And finally on May 23rd 2024, a farmer from Ituna, Saskatchewan, Canada found a similar object weighing several quintals.
All three belonged to Elon Musk's SpaceX. In fact, today the tycoon's private company is one of the leading producers of 'space junk'. In 2023 alone, SpaceX attempted 98 of the world's 223 orbital launches, leaving quite a lot behind. The company also currently has 5,420 Starlink satellites in orbit and plans to increase the number to over 12,000 (but rumors suggest it could reach over 40,000) in the next few years. SpaceX's satellites have an estimated lifespan of five years, which means the company will have to constantly send replacement satellites to keep the global network active. For critics, this is an incredibly wasteful approach. "I applaud SpaceX for developing reusable rockets," Moriba Jah, professor of aerospace engineering at the University of Texas and 'space intellectual', told Wired USA. "But we don't have reusable satellites. What we launch is equivalent to disposable plastic". Musk, however, has a plan: to use his Starships to allocate technologies to collect components and debris. But no detailed information on the project is currently available.
The issue remains high on the agenda of space agencies (Nasa, Esa, Isro) and aerospace organisations such as the Federal Aviation Administration, which has estimated that by 2035 some 28,000 hazardous debris will survive combustion during re-entry each year, injuring or killing one person on the ground every two years.
In 2023, ESA, during the November Space Summit, launched the Zero Debris Charter, a world-leading initiative that aims to make future space missions neutral by 2030. To date, more than 100 organisations worldwide have declared their intention to sign and join the collaborative effort in the coming months. "It is critical that we protect the future of our most precious and crucial space assets by keeping Earth orbits free of debris. By jointly signing the Zero Debris Charter, the different entities demonstrate global leadership in space debris mitigation and remediation", said Josef Aschbacher, ESA Director General, during the event in Seville.
According to Holger Krag, ESA's Head of Space Safety. "The Zero Debris community is committed to getting to grips with debris mitigation standards and technologies to make the clean and sustainable use of space a reality.” The approach will be based on debris mitigation and clean-up
technologies developed by ESA's Space Safety Programme.
SPACE WASTE COLLECTION TECHNOLOGIES
If the goal for aerospace designers is zero-waste satellites, it is still necessary to clean LEO from orbiting debris. One of the most promising techniques for capturing space debris is the use of nets and harpoons. These tools can be launched from service satellites to catch and collect debris. Nets are particularly useful for catching irregularly sized objects, while harpoons can pierce and hold more solid debris. One example is the University of Surrey's RemoveDEBRIS project, supported by a consortium of companies, including the giant Airbus, which has already carried out four tests, the last in 2023, using an experimental satellite was designed and built - and is operated in orbit - by Airbus' subsidiary Surrey Satellite Technology Limited (SSTL). The spacecraft is equipped with three Airbus technologies for active debris removal: a net and harpoon to capture space junk, as well as a vision-based navigation (VBN) system to validate in-orbit debris tracking techniques with cameras and LIDAR. At the time of publishing this article, the company has not responded to a request from the author to find out what the future uses of the system will be.
ESA also has its own sweeper satellite project, CleanSpace. It aims to develop a satellite capable of removing obsolete space objects and, according to an agency spokesperson contacted by the author, will see its first launch in 2026 to retrieve an out-of-use satellite that has been stuck in low-earth orbit since 2001.
There is no shortage of start-ups. Such as Seattle-based Starfish Space, backed by investors including Toyota Ventures, is working on a satellite removal spacecraft and, after a failed attempt to dock with a satellite in mid-2023, will try again early next year. Or ClearSpace, a spin-off of the Swiss space centre EPFL, which is developing a similar solution, especially for small debris. The start-up plans to remove the first debris from space by 2025.
Another potential technology involves the use of high-powered space lasers to change the trajectory of debris. By firing short AI-controlled laser pulses at debris, its speed and trajectory can be slightly altered, pushing it towards a decay orbit. This technique, developed by West Virginia University and still in the experimental stage, could become an effective solution to reduce the number of small debris in orbit. "Our goal is to develop a network of reconfigurable space lasers, along with a set of algorithms", Hang Woon Lee, director of the university's Space Systems Operations Research Laboratory, which is leading the project, said in a statement: "These algorithms will be the enabling technology that will make such a network possible and maximise its benefits. Combined with collection systems, it could optimise the trajectories and timing of space
scavengers.”
RECYCLING AT AN ALTITUDE OF 10,000 KILOMETRES
In addition to collection, recycling space debris represents a significant challenge and opportunity in the long term, especially for the development of an interplanetary civilisation and a considerable increase in space travel, including tourism and research. Recycling space waste (and recycling waste in space, as is already done on the ISS) could turn a problem into a resource, reducing the need to launch new materials from Earth.
Some projects are exploring the possibility of recycling materials directly in space. For example, metal debris could be collected and melted down to produce new structures or satellite components directly in orbit. This approach could reduce costs and the need to send new resources from Earth. This is why the ESA has a project developed with the aerospace industry called 'On-Orbit Manufacture, Assembly and Recycling' (OMAR), in fact the first integral circular economy programme in space.
In the not-too-distant future, we could see the construction of orbital recycling stations, where space waste would be collected, disassembled and transformed into useful materials. These stations could function similarly to a modern recycling station on Earth, with the difference that they would operate in microgravity. Another scientific (or science fiction) and circular option, the reuse of obsolete satellites. It is speculated that orbiting systems will be able to reuse satellites that are now out of service, using components that could be reused to build new satellites or as raw material for other space projects, outside the Earth's atmosphere. Or on future space colonies on the Moon, Mars or beyond.
By Emanuele Bompan