The exploration and utilisation of space is at an all-time high. In 2022, 2,409 tracked payloads or satellites entered orbit, the highest recorded to date. While that will certainly help advance humanity, the fact is that space is not as infinite as one would think. The majority of these payloads are commercial satellite constellations headed towards low-Earth orbits (LEO); an area known for harbouring space debris.
At last count, the European Space Agency (ESA) tracked 30,000 individual pieces of space debris measuring over ten centimetres lying at orbits below 2,000 kilometres. An additional one million objects over one centimetre in size, which are difficult to track, are estimated to be blanketing our planet. The sheer number of debris is seriously complicating the use and exploration of space.
“To put things into perspective, a decade ago we had about 1,500 active satellites in all. Now, we are launching more than 1,500 satellites in a year,” explains Tim Flohrer, Head of the Space Debris Office at the ESA. “From global navigation systems to precise weather forecasts, to even global trade and the performance of financial markets, our dependency on space-provided services and applications has increased. We have to ensure the reliability and safety of space as a resource.”
With the commercialisation of space growing, there is great interest among designers and operators of spacecraft, to have tools and mechanisms available to bring space sustainability as part of their business initiatives. The long-term sustainability of space application is important to them as it ensures long-term business prospects.
There is a mounting sense of urgency to mitigate the impact of space debris. In 2016, a fragment a few millimetres wide punched a 40-centimetre-wide hole in the solar panels of the satellite Sentinel 1-A. In another case, a piece of space junk smashed into the International Space Station in 2021, damaging a 60-foot robotic appendage. And in 2023, an old soviet satellite disintegrated after colliding with suspected space debris adding to the number of objects in space.
Experts worry that this trend, if allowed to continue, will unleash the Kessler Syndrome, where the amount of space debris reaches a tipping point creating even more space debris, leading to a snowball effect.
“We have seen in the last few years, with barriers and the cost of access to space decreasing, there is an increase in space traffic. It is not going to slow down. It is growing exponentially, and it is time that nations and organisations come together to find a way to handle this threat before it snowballs,” says Emmanuelle David, Executive Director of eSpace at the EPFL Space Center.
Here, David interestingly draws a comparison between junk in space and junk in our seas and oceans, hinting at how humanity could draw valuable lessons from one to tackle the other.
“Both space and the oceans are places that belong to everyone and for both, I have seen people assume they are infinite, and you can dump stuff into them without any repercussions. That is not true,” she explains. “Some researchers compare maritime law and space law, to see how we can put in place international regulations that will help the global space community use space sustainably.”
Taking that analogy to its conclusion, is there a way to mitigate the impact of space debris or will we see the equivalent of the Great Pacific Garbage Patch in space in our lifetime?
A lot of ideas are on the anvil. Some have tried to replicate ideas used in cleaning up our oceans, for instance, trawling space with a giant electromagnetic net to capture space debris. Other plans are considering the use of space tugs to tow debris to a specific area, allowing it to disintegrate on re-entry. Even more exotic plans are considering the use of ground and space-based lasers to nudge debris out of harm’s way.
While such active mitigation efforts are being studied, experts say an effective way to prevent further space debris is to stop it at its source. This includes setting in place rules and regulations to prevent space debris release and proliferation while creating sustainable standards to guide the next generation of space system design, operation, and recovery.
To meet this challenge, the World Economic Forum setup an international consortium alongside the ESA, the Massachusetts Institute of Technology, BryceTech and the University of Texas at Austin, to develop the methodology behind the Space Sustainability Rating (SSR), the first sustainability rating for space missions.
Large corporations, when they are planning a space mission could use the rating in their procurement strategy, mandating a specific level of sustainability to their partners. Governmental entities could use the rating as a reference point to assess the overall sustainability of a mission, making it easy to comply with upcoming international guidelines.
The SSR will use a rating system to score space missions on how they deal with space debris as well as other parameters to improve sustainability in space.
“With the commercialisation of space growing, there is great interest among designers and operators of spacecraft, to have tools and mechanisms available to bring space sustainability as part of their business initiatives. The long-term sustainability of space application is important to them as it ensures long-term business prospects,” explains Flohrer.
“From that perspective, the existence of the SSR helps incentivise good behaviour, both for governmental and private parties, allowing them to set in place rules and regulations that improve space sustainability,” he adds.
The SSR will assign a score to different types of space missions, keeping in mind efforts taken by the operators to mitigate space debris, choice of orbit, plans to de-orbit satellites after completion of missions, and the trackability of their payload from Earth.
Mission data shared by the operators, plus external data will be used to arrive at their SSR rating, which will then be made publicly available. eSpace has been selected to lead the roll-out of the SSR for different space actors.
“We will assess missions on these parameters and there is a final grade which is split into different stages such as bronze, silver, gold and platinum,” says David. “In practice, it means we can perform the rating from the early design space up until the end of life of these space vessels.”
The rating could then be used by the larger ecosystem surrounding space missions to decide on factors such as insurance, material use and even frequency of launches.
“Large corporations, when they are planning a space mission could use the rating in their procurement strategy, mandating a specific level of sustainability to their partners. Governmental entities could use the rating as a reference point to assess the overall sustainability of a mission, making it easy to comply with upcoming international guidelines,” adds David.
"In space, no one can hear you scream,” says the line from Ridley Scott’s Alien. But can they see you being sustainable?
While the SSR is a framework and not binding, both Flohrer and David believe that will lay the groundwork for a more systematic approach to classifying the sustainability of space missions. As the number and complexity of space missions scale up, initiatives like these could make a drastic difference in how humanity handles the final frontier.
“The SSR currently applies to satellites and space missions orbiting the Earth. Applying it to Moon missions or Mars missions will require rethinking the methodology, reevaluating what sustainability is for those missions, and redefining the KPIs. It will be an evolving process,” concludes David.
Photo credit: European Space Agency (ESA) - Taken by astronauts during the Proxima mission
