Orbital laser platforms could sweep away space debris

10 Oct 2023

West Virginia University proposes algorithm-driven network protecting spacecraft and satellites.

The space around Earth is a cluttered place, with debris from previous missions and multiple defunct satellites posing a significant challenge for any new satellites or manned spacecraft wanting to position themselves in low Earth orbit.

A project at West Virgina University (WVU) is researching an ambitious solution, in which space-based lasers would nudge debris on a collision course onto a different track and away from a target at risk.

Hang Woon Lee, director of WVU's Space Systems Operations Research Laboratory, envisages artificial intelligence-powered lasers maneuvering and working together to respond rapidly to debris of any size.

NASA is currently supporting Lee’s rapid-response debris removal study with $200,000 in funding per year for up to three years.

"Our goal is to develop a network of reconfigurable space-based lasers, along with a suite of algorithms," commented Lee. "Those algorithms will be the enabling technology that make such a network possible and maximize its benefits."

The problem has become more severe as space becomes increasingly cluttered, noted WVU. Earth’s low orbit has attracted new commercial telecommunications systems like SpaceX’s Starlink, which uses satellites to bring broadband internet to subscribers. Low orbit is also home to satellites used in weather forecasting and land-cover analysis, and it’s the staging ground for deep-space exploration.

"That increased population of objects heightens the risk of collisions, endangers manned missions, and jeopardizes high-value scientific and industrial missions," Lee said. Any collision in space can now potentially trigger the chain reaction termed the Kessler Syndrome, whereby the high density of junk ensures that each collision causes multiple further collisions in an escalating sequence.

Multiple lasers on target

WVU envisages space-based lasers which redirect their targets through laser ablation, vaporizing a small portion of the debris and generating a high-velocity plasma plume that pushes the debris off course.

"The process of laser ablation and photon pressure induces a change in velocity in the target debris, which ultimately alters the size and shape of its orbit," said Lee. "This is where the motivation for using lasers comes into play. The ability to change the orbit of debris can be effectively controlled by a network of lasers to nudge or deorbit space debris, avoiding potentially catastrophic events."

Use of lasers in this approach follows the increasing application of advanced optics to locate and track the hazardous space debris from the ground, such as the use of adaptive optics and laser guide-stars to help ground-based telescopes identify small, human-made objects in the night sky.

WVU's challenge will be to model the laser ablation process itself, where the complex shapes and orientations of the target objects make control of the outcome more difficult.

Previous NATO research into the use of ground-based lasers for the task concluded that a suitable installation to deal with medium-sized debris could be feasible within a decade, if the theoretical hurdles could be tackled. But WVU's orbital lasers represent a new and potentially more versatile approach.

"Using a system of multiple lasers can create multiple engagement opportunities with debris and lead to more efficient control of the trajectories," noted Lee. "Several lasers can act simultaneously on a single target at a greater spectrum of intensity, altering its trajectory in a way that would be impossible with a single laser."