Scientists use “tractor beam” technology to clean up space debris

Imagine two satellites colliding at incredible speeds high above the Siberian Peninsula.

This happened on February 10, 2009, when a discarded Russian satellite collided with a communications satellite called Iridium 33, creating more than 1,800 pieces of debris.

Although no one was injured, it was a wake-up call for aerospace engineers. The room was beginning to feel a bit crowded.

Currently, NASA estimates that about 23,000 pieces of space junk the size of a softball or larger are orbiting our planet.

Each piece increases the risk of another crash like the one that destroyed Iridium 33, and the potential damage could be even worse next time.

Julian Hammerl, a graduate student at CU Boulder, explains that space debris causes a domino effect. When one piece of junk hits another, even more debris is created, increasing the likelihood of collisions. This is called the cascade effect.

But Hammerl and his team led by Professor Hanspeter Schaub have a pioneering idea to stop these chain reactions: tractor beams.

Just like in Star Trek, these beams could be used to safely take out asteroids and other threats.

Here’s the idea: In the future, we could send small spacecraft into orbit to rendezvous with the old, non-functioning satellites orbiting the Earth. Armed with devices called “electron beams,” these spacecraft would slowly bring the debris to safety without having to touch it. It’s similar to how static electricity can cause your socks to stick to your pants.

Schaub, who heads the aerospace engineering department, says it’s a bit like the tractor beam from Star Trek, but not quite as powerful.

The research team still has a few challenges to overcome, including understanding the complex environment around Earth and how the tractor beams could help clear debris from the region of space between the Earth and the Moon.

The research team works on these problems with the help of a special laboratory that can simulate conditions in space. It uses a vacuum chamber to mimic Earth’s environment, filled with a thin gas of free electrons and charged atoms called plasma.

The team hopes their tractor beams can help free up valuable space in Earth’s geosynchronous orbit, some 22,000 miles from the surface.

This region is home to some of the most advanced satellites ever built, but it also always gets crowded. Tractor beams could help move old satellites out of the way to make room for new ones.

The team’s “electrostatic tractor” idea is similar to rubbing a balloon on your head to make your hair stand on end. A spaceship would approach a piece of space junk and bombard it with an electron beam.

This would create a negative charge on the debris and a positive charge on the spacecraft, and since opposites attract, the spacecraft could then “pull” the debris away.

This may sound simple, but it is quite complex. Old satellites, for example, don’t just sit in one place—they can tumble wildly through space. By feeding them pulses of electrons, the researchers believe they could slow the satellites down, making them safer to move or repair.

Looking further ahead, the team is also considering the space between the Earth and the Moon, an area that will soon become much busier. Conditions here are very unpredictable due to the solar wind, a stream of plasma emitted by the Sun. This could affect the performance of an electrostatic tractor.

Schaub is optimistic that with the right funding, his team could be ready to send a prototype tractor beam into space within the next five to 10 years.

He stresses that this technology could help move multiple objects during their lifetime, significantly reducing costs. After all, no one wants to spend billions just to move space debris.

Source: University of Colorado at Boulder.