Scientists Discover a Way to Push Space Junk With Powerful Lasers — Could This Technology Clean Up Earth's Orbit?

Every night, thousands of satellites orbit Earth, supporting essential services such as GPS navigation, weather forecasting, communication, television broadcasting, and scientific research. But there is a growing problem threatening this valuable infrastructure: space debris.

From abandoned satellites and discarded rocket parts to tiny fragments created by collisions, Earth's orbit is becoming increasingly crowded with objects moving at extremely high speeds. Even a small piece of debris can seriously damage or destroy a functioning spacecraft.

Now, researchers led by Raoul-Amadeus Lorbeer have demonstrated a promising approach that could help address this growing problem. Their technique uses powerful laser pulses to push small pieces of space debris without physically touching them.

The experiments showed that laser pulses could generate measurable thrust, increasing the speed of representative debris objects by more than 0.3 metres per second per pulse under specially controlled experimental conditions.

This research could bring scientists one step closer to developing laser-based systems capable of controlling and eventually removing dangerous space debris.

Why Is Space Debris Becoming a Serious Problem?

Space debris refers to human-made objects in orbit that no longer serve any useful purpose. These include broken satellites, abandoned spacecraft, rocket stages, and fragments produced by explosions or collisions.

The problem is particularly serious in Low Earth Orbit (LEO), which extends from a few hundred kilometres above Earth's surface to approximately 2,000 kilometres.

This region contains some of the world's most important space infrastructure, including the International Space Station (ISS), the Hubble Space Telescope, weather-monitoring satellites, and communication networks.

As more countries and private companies launch satellites, the number of objects in this region continues to increase.

The biggest danger is their speed. Objects in low Earth orbit can travel at several kilometres per second. At these velocities, even a tiny fragment measuring just a few millimetres can damage sensitive satellite equipment.

Larger fragments can cause catastrophic collisions, potentially destroying entire spacecraft and producing thousands of additional pieces of debris.

One example was the 2009 collision between the American Iridium 33 satellite and the Russian Cosmos 2251 satellite. The incident created a large cloud of debris, adding to the growing congestion in Earth's orbit.

The International Space Station also has to perform collision-avoidance manoeuvres to reduce the risk of being struck by dangerous objects.

Unfortunately, tracking smaller debris is extremely difficult. Many centimetre-sized objects are too small to be reliably monitored using existing tracking systems.

This creates a dangerous situation: spacecraft operators may not even know that a small fragment is approaching until it is too late.

Could Powerful Lasers Push Space Junk Away?

Scientists have proposed several methods to remove dangerous space debris.

Some approaches involve sending spacecraft into orbit to capture large pieces of debris and bring them back toward Earth. Other techniques aim to increase atmospheric drag, gradually slowing objects until they fall into the atmosphere and burn up.

However, physically collecting thousands of small fragments would be extremely difficult, expensive, and time-consuming.

This is where laser-based debris removal becomes interesting.

Instead of sending a spacecraft to capture each object, scientists want to use powerful lasers to influence the movement of debris from a distance.

The basic idea is surprisingly simple: use laser energy to create a small amount of thrust that changes the object's movement.

If the movement of a debris fragment can be altered enough, its orbit could potentially be adjusted so that it eventually enters Earth's atmosphere and burns up.

Another possibility is to change its trajectory slightly, helping prevent a future collision with an operational satellite.

How Does the Laser Technology Work?

The technique demonstrated by Lorbeer and his research team is based on a process known as laser ablation.

Laser ablation occurs when an extremely powerful laser pulse hits the surface of a material and heats a very thin layer to an extremely high temperature.

This causes some of the surface material to vaporize and rapidly expand away from the object.

According to Newton's third law of motion, every action produces an equal and opposite reaction.

As the vaporized material moves away from the surface, it produces a reaction force in the opposite direction. This force creates a small push, or thrust, on the debris object.

In simple terms, the laser works like a tiny rocket engine without needing to attach any fuel tank or mechanical device to the debris.

By carefully controlling the laser pulses, scientists may be able to influence the object's movement without making physical contact.

This is particularly useful because most space debris is uncontrolled and cannot easily be approached or captured.

What Did the Researchers Demonstrate?

Previous experiments had explored laser-generated thrust, but many were conducted under simplified conditions.

For example, researchers often faced limitations involving laser energy, target size, material, shape, movement, and surrounding pressure.

Lorbeer and his colleagues wanted to investigate whether the technique could work under conditions that more closely resemble real space debris.

To achieve this, they conducted experiments using representative targets measuring approximately one to two centimetres.

The team used a powerful laser system operating at a wavelength of 1064 nanometres. Each laser pulse delivered energy of up to 80 joules, producing average energy concentrations, known as fluences, of up to 10 joules per square centimetre.

The experiments were performed in an evacuated microgravity environment to reproduce important aspects of the conditions experienced by objects in space.

The researchers investigated how different parameters influenced the generated thrust, including the target material, surrounding pressure, and angle at which the laser struck the surface.

The results showed that the thrust effects followed the expected trends predicted by their computer simulations.

Most importantly, the researchers achieved speed changes exceeding 0.3 metres per second per laser pulse.

This demonstrated that laser ablation could generate a meaningful impulse on small, freely moving objects under realistic experimental constraints.

Could This Technology Clean Thousands of Space Debris Fragments?

One of the biggest advantages of laser-based debris removal is that it could potentially operate from Earth.

Rather than launching a separate spacecraft to capture every small fragment, a powerful ground-based laser facility could target multiple debris objects as they pass overhead.

The researchers point out that such a system could potentially remove hundreds of particles per day.

This is particularly important because there are hundreds of thousands of small debris fragments in orbit that are difficult to track individually.

Previous research has also suggested that laser systems could potentially generate the required energy concentration over distances approaching 1,000 kilometres.

If these capabilities can be developed into a reliable operational system, laser technology could become an important tool for reducing the number of dangerous objects in Earth's orbit.

However, this does not mean that scientists can already remove space debris using an operational laser facility. The current results represent an important experimental demonstration rather than a fully developed cleanup system.

What Happens Next?

Although the initial results are promising, several important challenges remain.

The researchers plan to investigate how different materials respond to laser pulses and how laser ablation behaves when objects break apart or become fragmented.

They also want to improve their ability to predict and control changes in debris orbits.

Another important goal is increasing the laser energy concentration reaching distant targets.

For this purpose, the team is exploring a technique called passive three-beam interference. The approach is intended to increase the laser fluence at the target by at least a factor of three.

Improving this capability could make it easier to influence small debris fragments over much greater distances.

Scientists will also need to address practical challenges such as accurately identifying targets, tracking their movement, focusing laser energy, and ensuring that the technique does not unintentionally create additional debris.

A Cleaner Future for Earth's Orbit

Space has become an essential part of modern life. Satellite technology supports communication, navigation, weather forecasting, disaster monitoring, and scientific discoveries.

But as human activity in space increases, protecting Earth's orbital environment is becoming just as important as launching new spacecraft.

The research by Raoul-Amadeus Lorbeer and his colleagues demonstrates a possible way to influence small space debris using powerful laser pulses without physically touching it.

If future developments overcome the remaining technical challenges, this approach could help scientists manage the growing debris population and protect valuable satellites.

The ultimate goal is simple: make Earth's orbit safer and ensure that future generations can continue exploring and using space.

Because space is precious, and keeping it clean is becoming one of humanity's most important technological challenges.

Reference: Lorbeer, RA., Zwilich, M., Zabic, M. et al. Experimental verification of high energy laser-generated impulse for remote laser control of space debris. Sci Rep 8, 8453 (2018). https://doi.org/10.1038/s41598-018-26336-1