Space companies are racing to find ways to drag more than 2800 defunct satellites out of danger. But there are likely more than one million smaller but deadly fragments that pose an even greater risk.
1. Orbital garbage collector
The Adelaide-based space company Paladin Space, founded in 2018, is proposing an innovative solution for cleaning up space debris or orbital debris. The pioneering tech — an orbital “street sweeping” — is said to be capable of collecting fragments of space junk before disposing of them in the Earth’s atmosphere or delivering them to future space recycling foundries. Paladin’s reusable orbital garbage collector is designed to “swallow” a bellyful of debris in a single mission, offloading the unwanted cargo, and returning to the job.
It doesn’t matter what the size is [space debris] if it’s travelling 7.5km a second, it’s a huge danger to anyone or anything up there.
Harrison Box, founder of the orbital “street sweeping” startup Paladin Space
Box explained that the company’s tech design doesn’t pose a threat to active satellites and it can’t be misused as a weapon. The approach is built on scooping up fragments and other small items. Up front it will feature an armoured collection scoop, while everything else is positioned behind it, with the solar arrays folding to avoid becoming debris themselves.
Once it opens its “mouth”, the debris will flow into a lightweight container. Box’s zero-gravity “contents manager” is a sheet of Kevlar that unrolls over the mouth once the fragment is inside. Then it draws the object down to the container’s back end. When the trash compactor begins hunting more metal scraps, the “mouth” closes, and the Kevlar sheet rolls back up in readiness for the next harvest.
2. Space debris
According to the European Space Agency (ESA) Space Environment Report 2022, “more than 30,000 pieces of space debris have been recorded and are regularly tracked by space surveillance networks”. But the “real number of objects over one centimetre long is probably more than one million”, warns the agency. Among the 7,790 intact satellites currently in orbit, only 4,800 are functioning, ESA said.
With Paladin Space’s new tech, recovery rates of space debris would exponentially grow in an efficient way: “ESA is currently paying 100 million euros to remove just one item of space junk. That’s the value they put on the job,” said Box. “Imagine the value of being able to remove hundreds”.
Addressing a panel session at the World Economic Forum in Davos, Switzerland, last January, ESA Director General Josef Aschbacher said discussions were ongoing with the agency’s member states about a “zero debris policy“ that would require satellites to be deorbited immediately after the end of their missions.
“We want to establish a zero debris policy, which means if you bring a spacecraft into orbit you have to remove it,” he said. “This policy should be in place in a couple of years.” Currently, international guidelines, adopted by many countries, allow satellites to remain in orbit up until 25 years after the end of their mission.
3. Space junk incidents
There have been numerous space junk incidents that have occurred over the years. Last December, a tiny fragment punched a hole in the Soyuz return capsule docked at the International Space Station (ISS), causing it to vent its atmosphere. In 2020, a piece of space debris narrowly missed the ISS, forcing the crew to take shelter in the Soyuz spacecraft.
Another episode happened in 2009, when two satellites — Iridium 33 and Kosmos-2251 — collided in low Earth orbit, generating more than 2,000 pieces of trackable debris. When China conducted an anti-satellite missile test, in 2007, it destroyed one of its own defunct weather satellites, generating over 3,000 trackable pieces of debris.
