Near-Earth space is rapidly turning into a landfill: Tens of thousands of fragments of inactive satellites and rockets have accumulated in orbit. Each of them, traveling at speeds of up to 28,000 km/h, poses a potential danger to existing space missions. The problem is so threatening that experts warn of the risk of the Kessler effect, an avalanche-like cascade of collisions that could make an orbit unfit for flight. So, how do we remove this debris? Today, engineers are testing a variety of technologies to clean up Earth orbit. Let’s focus on the most interesting current and promising solutions that allow us to remove large debris (over 1 cm) and thus make space safer.
Available methods
Today, engineers already have several solutions that allow them to start “cleaning” space debris. Some of them, such as nets, harpoons, and robotic manipulators, have successfully passed their first tests in real space conditions. Although most projects are currently focused on test missions with one or two objects, these technologies have already proven their worth and paved the way for systematic cleaning of the most dangerous debris.
Nets and harpoons
One of the most obvious solutions is to “catch” the debris with a net or harpoon. The principle of operation is as follows: a strong net is fired from the space “cleaner”, which opens and entangles the debris, or a harpoon is released on a tether that sticks into the target. Once the debris is captured, it is de-orbited to be destroyed in the atmosphere. The technology was successfully tested on the RemoveDEBRIS experimental satellite in 2018 – it caught a mock debris with a net from a distance of ~7 meters and fired a harpoon at the target.
Efficiency: one net or harpoon captures only one object at a time, but the vehicle can carry multiple nets/harpoons for multiple targets. Clearance time: the capture itself takes seconds, but it can take weeks to get close to the target and re-enter the atmosphere.
Such methods have already proven their effectiveness, but they are disposable tools that are suitable for relatively small objects and require very precise aiming.
Robotic manipulators
A more versatile approach is to grab the debris with a robotic arm or claw, just as they do on the International Space Station. To do this, an autonomous navigation satellite approaches an uncontrollable object and then activates a gripper (a manipulator or several mechanical “arms”), reliably grabbing the debris. Then the satellite’s engines change the bundle’s orbit, dropping it into the atmosphere to burn. The first real mission using this approach, ClearSpace-1 by ESA, is scheduled for 2028. The four-fingered clawed device is supposed to capture a 112-kilogram debris (a part of the Vega rocket) in orbit (~700 km) and bring it down into the atmosphere. This technology is still very expensive – the ClearSpace-1 mission received €86 million in funding from ESA (and the total cost is about €100 million) for the removal of one object.
Efficiency: Current robotic cleaners can remove one large piece of debris at a time, but in the future, it is planned to equip them with the ability to make multiple grips in a row. Cleanup time: It typically takes several months to approach, grab, and control the removal of a single large piece of debris.
Robotic “cleaners” are versatile and capable of gripping massive objects, but they are currently extremely expensive, so work is underway to reduce the cost and reuse of such systems.
Magnetic grippers
This technology requires a conscientious attitude from developers to the problem of orbital debris. A ferromagnetic “flag” plate is installed on board the potential debris. A cleaner satellite equipped with an electromagnet flies up and attracts the uncontrolled vehicle. Then it either tows it down to burn in the atmosphere or transfers it to a “cemetery” – a safe disposal orbit. In 2021, the Japanese company Astroscale tested this method (ELSA-d mission), and in 2026, it plans to remove a real inoperable satellite for the first time (ELSA-M mission).
Efficiency: the method works only for objects specially equipped for magnetic docking – it will not help with old garbage without such tags. The advantage is that one cleaner can sequentially remove several prepared satellites without complex manipulators. Cleaning time: Magnetic convergence and capture take a few hours, and deorbitation of one captured satellite takes several weeks.
Magnetic grippers are effective for “scheduled” decommissioning of satellites. If satellite manufacturers start adding docking tags on a massive scale, such cleaners will be able to quickly clear the orbit of new “dead” satellites.
“Sail” or “drag sail” system
A drag sail is a thin and lightweight membrane that is deployed to increase the area of a satellite or debris. This increases the object’s drag in the remnants of the atmospheric environment in low Earth orbit (LEO). Even a low atmospheric density at altitudes of 500-700 km begins to slow down a sail object, and it descends from orbit faster.
Such a sail has already been successfully tested on several small satellites (e.g., LightSail and NANOSAIL-D missions). Some modern commercial Earth monitoring satellites have built-in “parachutes” or sails to automatically self-destruct in the atmosphere after the mission, reducing the time spent by unmanaged debris in orbit. The cost of this method is relatively low, as the system consists of a lightweight membrane and a simple deployment mechanism. For small satellites, it can be quite inexpensive.
Image: vestigoaerospace
Efficiency: Drag sail works best in low orbits, where atmospheric resistance is more significant. In higher orbits (over 800 km), the efficiency decreases. Clearance time: Usually accelerates orbit decay several times compared to natural “falling”. For a small satellite, the time can be reduced from tens of years to just a few months or years, depending on its initial altitude.
“Sail” is a relatively simple and affordable technology for removing new satellites when they are finished. However, it again does not solve the problem of old debris if it is not equipped with a sail in advance.
Promising methods
Along with the methods that are already getting their first practical results, promising future technologies are being developed: laser “pushing”, ionic “towing”, and electrodynamic tethers. These technologies allow for contactless influence on the orbit of unguided objects and can, in the future, simultaneously “service” dozens or even hundreds of debris. Although these approaches are still at the stage of experimentation and design development, the success of the first demonstration missions will be a crucial step towards large-scale clearing of near-Earth space.
Electrodynamic tethers
The method is based on the use of the Earth’s magnetic field to brake the debris. A long tether is attached to the debris, and an electric current is passed through it. The interaction of the current with the planet’s magnetic field creates a force that gradually lowers the object’s orbit. Japan’s JAXA tried to deploy a 700-meter tether (the KITE project on HTV-6) in 2017, but the experiment failed. Currently, research is underway on smaller CubeSats and the EDDE (ElectroDynamic Debris Eliminator) concept system in the United States.
The picture shows a modular 10-kilometer EDDE (ElectroDynamic Debris Eliminator) system, which has a long conductor in the center, which serves as the main “core” for the passage of electric current. At both ends of this tether are Net Manager units with integrated debris-catching mechanisms, as well as one “Emitter” that creates and controls the current in the conductor. Along several 1-kilometer segments, solar panels are attached to power the system so that the same current can interact with the Earth’s magnetic field and change the object’s orbit. Thanks to this design, the EDDE acts as an electrodynamic “tugboat”: it can move between different fragments of space debris, change their orbit, and guide them to the atmosphere for combustion.
Efficiency: Calculations show that several EDDE-type spacecraft could remove all large objects in low earth orbit in about a decade. Clearance time: The orbit reduction of a single object using a tether can last from several months to several years, depending on the mass and parameters of the tether.
Electrodynamic tethers are a promising technology for massive orbital cleaning with almost no fuel consumption, but so far, they lack successful full-scale tests.
Laser technologies
Small debris can also be removed remotely, from Earth or space, using a laser. For example, a powerful laser beam is focused on a piece of debris, heating its surface and vaporizing the material. This creates a jet thrust that slightly changes the speed of the debris. If you regularly “push” the object with laser pulses, its orbit will gradually decrease, and eventually it will burn up in the atmosphere. The concept of a “laser broom” has been discussed since the 1990s, and it is currently at the experimental level. Different countries (Japan, China, Australia) are already testing ground-based and orbital lasers for garbage collection. You can read about the latest developments in laser technology in our article “Star Wars is here: what laser weapons are and how they could change air defense systems”.
Efficiency: Lasers are best suited for small fragments (≈1-10 cm) that are difficult to capture by other means. Theoretically, one powerful laser can adjust the orbits of hundreds of small fragments in a year, gradually clearing a certain range of heights. Clearing time: the impact on one object has to be repeated many times over days or weeks – this gradual nudging requires patience.
The laser method is attractive because it does not require the launch of space “garbage collectors”, but it requires super-powerful lasers and very precise tracking of each target.
Ion (plasma) “tow”
The Ion Beam Shepherd (IBS) uses an ion (or plasma) engine to fire a narrow charged beam toward the debris. This “stream of ions” acts as a remote pusher: a small reactive force changes the orbit of the debris without coming into physical contact with it. As a result, the debris gradually slows down and descends until it burns up in the atmosphere.
This is a promising technology that is still being developed at the level of conceptual and ground experiments. The European Space Agency (ESA) and several university laboratories in Europe and the United States are conducting bench tests to develop prototype ion engines with the proper beam direction. In practice, IBS has not yet been launched into space for commercial cleaning. The cost of such a project is not yet known, but it is expected that a mission with an ionic tug may be cheaper than projects with robotic manipulators (due to the lack of complex mechanical systems).
The colored rings on the engine nozzle symbolize the intensity distribution of the beam, which, without physically touching the target, gives it a slight but constant acceleration.
Efficiency: one device is capable of “pushing” several objects in a row if its engine has a sufficient service life and a supply of working fluid (ionization gas). At the same time, the ion beam needs to be aimed very accurately, especially if the debris is rotating. Cleaning time: The orbital decay of a single large piece of debris can last from several weeks to several months, depending on its mass and orbital parameters.
The Ion Beam Shepherd is an interesting option for contactless debris removal that can potentially work with objects of various sizes. The main advantage is the absence of complex gripping mechanisms. However, the technology still requires comprehensive space tests to confirm the reliability and accuracy of the “nudge”.
The orbit of the future: Is it possible to clean it completely?
If we stop launching satellites without a launch plan and set strict requirements for operators (so that all new satellites have a de-orbit mechanism), we can significantly reduce the amount of new debris. Experts estimate that low orbit will begin to naturally “self-clean” within 2-3 decades due to atmospheric braking. However, higher orbits will require tens or even hundreds of years without active intervention. That is why a combination of different technologies capable of actively removing heavy and hazardous debris is needed to achieve faster results.
Ultimately, the goal is to provide a clean and safe orbit for future scientific, commercial, and exploration missions. By combining already available methods (nets, robotic manipulators, “sails”) and promising developments (lasers, ion tugs, magnetic grippers, tethers), we can stop the growth of fragments and gradually free the orbit from dangerous “debris ballast”.
