The amount of space junk around Earth has hit a critical point where it now poses risks to other spacecraft and satellites and has started to trigger human efforts to combat the security threat in outer space.
A spaceship glides effortlessly through the darkness. A flyby hand-sized metal plate appears as a flash of light, then slams head-on against the space shuttle. Can you hear me, Major Tom? Ground control loses contact with the ship. To the last beats of David Bowie’s Space Oddity, the spacecraft uncontrollably slips away into the void.
A totally fictional scenario? By no means.
Space debris is comparable to the problem of plastic waste on Earth – with the difference being that the approximately 6,500 tons of junk in orbit can turn into dangerous projectiles.
According to the European Space Agency’s (ESA) latest Annual Space Environment Report, the number of out-of-control objects larger than 10cm in diameter reached about 34,000 in January 2019.
These include broken satellites and splinters created during collisions and explosions. As the amount of cosmic waste increases exponentially, it’s not just the large junk pieces that are causing experts a serious headache.
In August 2016, a fragment only a few millimetres thick hit the Earth observation satellite Sentinel-1A, drilling a 40 cm hole in the solar panel of the satellite, which is funded by the EU’s Copernicus programme.
The spacecraft was just able to compensate for the resulting energy loss and continue the mission. Experts believe it could have been far worse.
“When an aluminium ball of just one centimetre in diameter strikes a satellite, it has the energy of a mid-range car driving into it at about fifty kilometres per hour,” explains Heiner Klinkrad, space debris manager at ESA.
These small pieces of debris pose a serious threat to the sustainability of space missions, according to ESA projections. Due to their small size and high orbital speed, the splinters are often impossible to track and still have the power to seriously damage equipment, destroy satellites or even jeopardise space missions.
According to the space agency’s estimates, more than 900,000 pieces of such debris, fractions over one centimetre in size are currently swarming through the Earth’s orbit.
Space experts expect even more cosmic waste in the future. “Because of continued space activity and new satellite launches, but also because of plans for new concepts involving mega-constellations of hundreds or thousands of satellites, we expect this trend to increase,” Sebastien Moranta, of the European Space Policy Institute in Vienna, told EURACTIV.
The space sector will have to think about ways to ensure better sustainability of the space environment and its security, he said.
“In addition to eliminating space junk, it’s about standards for more eco-friendly satellites, better communication between satellites and space operators, better orbital traffic management, and systems protection technology,” Moranta added.
While NASA and global companies like Airbus are already researching the problem, Europeans intend to add innovative solutions to combat space debris with ESA’s CleanSpace Initiative.
“We want to minimise the impact of space activities on the environment, so we need to be innovative and adopt new technologies,” Luisa Innocenti, director of the ESA initiative, told EURACTIV.
CleanSpace aims to eliminate space junk but also to make future space missions much more sustainable using new technologies so that as little new waste as possible is produced.
But the cleaning part of the endeavour is already a logistic task of mammoth proportions. The potential ‘catching and bringing-back-the-earth’ approach is a mission that has never been done before, though CleanSpace wants to make it possible in the future.
The plan for actively removing space debris involves three phases: First, a cleanup satellite navigates towards the wreckage in a so-called Rendezvous and Proximity Operation (RPO), then captures it before the satellite either returns the object to Earth, into the atmosphere or sends it into another distant orbit leading away from Earth.
But in addition to the technical obstacles, space cleaners are facing a huge financial challenge.
“The removal of existing satellites currently cannot be commercial, nobody wants to pay for it,” Innocenti told EURACTIV. “The only way is to levy a tax on future launches so that money is put aside for later clean-up activities.”
Once the technology adapts to the removal of larger objects, Innocenti believes that the removal process could be commercialised at a later stage.
A first commercial trial run has already been announced: Japanese company AstroScale is planning a first demonstration mission to remove space junk in 2020.
“At the moment, however, the whole procedure is still far too complex,” Innocenti believes.
Meanwhile, she points towards other solutions for the space industry. Much of the space debris, for example, is caused by battery explosions. Those batteries, which are connected to the solar system of the satellites, can overheat after the end of their life and explode if they are not removed beforehand.
New technologies could find a way to separate these batteries more easily after the death of a satellite and avoid blasts that tear them into pieces.
Moreover, in addition to the increasing commercial use of the cosmos, geopolitical and security interests could create another problem.
As defence ministries of the US, China and Russia are currently working on their space force concepts, this type of civil-use technology has a potential dual-use aspect, Innocenti acknowledges.
“Whatever we do from a purely civilian, technological point of view can also be used for military purposes – robot arm can seize space debris parts, but just as well grab enemy satellites.”
“We are at a crucial moment because so far we have been able to operate in space without having to worry about the impact of human activity,” Moranta, of the European Space Policy Institute, said. “And now we have to think realistically about killer factors in space.”
[Edited by Zoran Radosavljevic]
***An earlier version of this article has been published in a Special Edition of the German newspaper “Das Parlament”.