Kazunori Takahashi is an associate professor at the Graduate School of Engineering, Tohoku University, Japan. To combat the growing threat of space debris, he’s advanced an innovative new model to improve safety. His approach uses a cusp-type bi-directional radiofrequency plasma thruster that would ablate junk without any physical contact.
The staggering amount of space debris is constantly increasing. This dramatic increase all but guarantees collision with operational satellites and spacecraft, something Takahashi is quick to point out is an ever more pressing concern.
This revolutionary propulsion system works to actively deorbit space debris. Sooner or later, the debris is going to re-enter the Earth’s atmosphere and burn up on re-entry. The propulsion engine works by ejecting two streams of plasma in opposite directions: one aimed at the target debris and another in the opposite direction. This dual ejection mechanism essentially produces an active deceleration effect. In doing so, it helps slow the debris enough to escape its orbit in roughly 100 days.
Growing Threat of Space Debris
The growing threat of space debris, for example, is a major concern for both today’s and tomorrow’s space activities. Kazunori Takahashi highlights that “owing to their uncontrolled motion and velocity exceeding that of bullets, [space debris] orbiting around Earth pose a serious threat by significant increase in the potential risk of collisions with satellites that support sustainable human activity in space.”
Satellites and spacecraft are indispensable for communication, navigation, and understanding our planet’s climate and weather. The increasing debris field, with more than 100,000 identifiable pieces of space junk, now endangers these critical missions. Takahashi’s approach addresses this threat in a meaningful way, utilizing next generation plasma propulsion technologies to provide safe controlled re-entry and removal of threatening debris.
Current solutions for active space debris removal mostly include direct-contact methods, which pose the danger of collision with uncontrolled debris during contact. Takahashi points out that “most current space debris removal methods are direct-contact approaches and carry the risk of becoming entangled in the uncontrolled motion of debris.” Unlike these systems, his plasma thruster system works to decelerate, making it a much safer option.
Technological Advancements in Plasma Propulsion
The cusp-type bi-directional radiofrequency plasma thruster is a recently developed disruptive technology that is driven by a need for faster and more efficient space debris removal. Takahashi describes a particularly special type of magnetic field, known as the “cusp.” This new innovation greatly increases the deceleration force being applied to the targeted debris.
“This propulsion engine applies deceleration force to the target object by ejecting plasma, while avoiding excessive thrust on itself by ejecting another plasma plume in the opposite direction,” Takahashi explains. This advanced mechanism provides an effective solution for navigating safely through space debris. Doing so greatly reduces the potential harm that direct contact can pose.
Laboratory experiments convincingly proved this technique to be effective. This represents an important move ahead in creating smart debris removal policies. The findings from Takahashi’s study were published on August 20, 2025, in Scientific Reports. Read the article, DOI 10.1038/s41598-025-16449-9.
Future Implications for Space Operations
As missions to space grow more numerous and complicated, now is the time to tackle the impending crisis of space debris. Takahashi’s work certainly adds more flame to the discussion on responsible space exploration. It serves as a tangible model for protecting orbital landscapes.
“This achievement represents a significant technological advancement toward developing a propulsion system capable of efficiently and safely removing space debris,” he remarks. The global implications of this research will be significant, providing new tools to enable safer and more sustainable use of outer space.