A better way to detect space debris

Imagine trying to spot a tiny paint chip floating in space. While even small debris like paint chips may seem harmless, it can severely damage satellites due to the extreme speeds involved. Currently, we can't detect objects smaller than a marble in space, leaving satellites vulnerable to impacts from smaller debris.

Space debris is a growing crisis for satellite infrastructure that we rely on for GPS, communications, and weather forecasting. While we can track and avoid larger debris, millions of pieces smaller than a marble are essentially invisible with current technology. These tiny objects, traveling at speeds over 10 km/s, can disable or destroy satellites worth hundreds of millions of dollars, directly impacting our day-to-day lives here on Earth.

In a recent featured article in the journal Physics of Plasmas, my co-authors and I explored an innovative detection method using special waves that naturally occur in space plasma - the electrically charged gas that surrounds Earth. These waves are unique because they can travel long distances while maintaining their shape, similar to how a tsunami crosses an ocean. When debris moves through space plasma, it creates these waves, which could potentially be detected by current detection methods.

Using advanced computer simulations, we studied how these waves actually behave. Previous theories made simplified assumptions, but our work revealed that electrons get trapped within these waves — like surfers riding an ocean wave — significantly affecting wave behavior. Understanding these effects is crucial if we want to use these waves for debris detection.

Our findings provide a more accurate picture of wave behavior in space, helping bridge the gap between theory and practical applications. The next step is to determine whether these waves can last long enough in real space conditions to be useful for debris detection, potentially leading to better ways to protect satellites from the growing danger of space debris.

Our research is important for three key reasons:

• It explores a potentially groundbreaking method for detecting small debris using natural plasma waves in space, which could fill a critical gap in our current detection capabilities.
• It provides rigorous computer simulations of how these waves actually behave, showing that previous simplified theories missed important effects.
• It lays the groundwork for future work on wave damping which will help determine if this detection method is practically feasible, potentially saving significant time and resources in developing debris detection systems.

In my research at Stanford, I’m studying the propagation of these waves over very large time and length scales. It’s impractical to simulate every aspect through computer modeling, which is why analytical models are crucial for such studies. In fact, this field has emerged largely from a foundation of key analytical models. Until our study, no one had thoroughly evaluated the accuracy of these models. We demonstrate the limitations of currently used models and propose improvements to them. This work represents a step toward developing better analytical models for such studies, protecting space technology from debris, and using this technology to improve life on Earth as we know it.

Ashwyn Sam (2020 cohort) is pursuing a PhD in aeronautics and astronautics at Stanford School of Engineering. He aspires to push the frontiers of space exploration while also aiming to impact global discoveries in renewable energy by researching novel propulsion technologies. Learn more about Ashwyn’s journey in his Imagine A World interview.

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