Researchers from the University of Michigan have outlined an innovative approach to spotting space debris that escapes radar visibility due to its tiny size. The study, published on the institution’s official science site, explores how electrical activity generated by microscopic fragments can reveal their presence far beyond traditional tracking limits.
Space agencies estimate a vast amount of debris orbiting Earth. According to the European Space Agency, as of November 2023 there were about 35,600 pieces of debris larger than 10 centimeters in Earth orbit, largely comprising old satellite components, spent rocket stages, and assorted fragments. Beyond these larger pieces, well over 130 million tiny fragments remain in near-Earth space, many of which are invisible to conventional radar and optical methods on the ground.
UMICH researchers observed that when two objects collide at orbital speeds, which can reach up to 30,000 kilometers per hour, a strong electrical pulse is generated. Ground-based radio telescopes were able to record these bursts, confirming that such events emit detectable signals despite their small size. The same collision process also charges debris pieces, causing them to emit brief, visible sparks as they approach other charged fragments.
While the electrical impulses are brief and relatively weak, they carry valuable information. The team demonstrated that these signals can help pinpoint the location of objects as small as one millimeter—roughly 100 times smaller than what current radar tracking systems can reliably detect. This could dramatically expand awareness of the smallest debris threats in crowded orbital environments.
Looking ahead, the researchers aim to refine the method to extract more than just coordinates. They plan to determine debris material properties and geometric shapes from the electrical signals, enhancing the ability to characterize and categorize orbital debris without sole reliance on expensive space-based assets.
Earlier investigators have proposed several strategic options for mitigating space debris. These include improving end-of-life practices for satellites, developing active debris removal techniques, and strengthening international standards for debris generation and collision avoidance. The new electrical-signal approach adds a complementary tool to the existing array of tracking and mitigation strategies, potentially offering sooner detection of the smallest threats and informing more effective protective measures for active spacecraft. [Source attribution: European Space Agency (ESA) and related academic publications]