Key Points
- Scientists have a new algorithm to track the dangerous tumbling of space debris from Earth.
- The tool analyzes an object’s changing brightness (its “light curve”) to determine its spin.
- This is a difficult “inverse problem” because the data can be confusing and ambiguous.
- The new AISwarm-UKF algorithm employs thousands of initial guesses to identify the most accurate solution.
Scientists have developed a powerful new algorithm to help solve the growing problem of space junk. With tens of thousands of large pieces of debris orbiting Earth, a new tool is needed to figure out how these objects are tumbling before we can safely remove them.
Understanding the spin of a piece of space junk is extremely difficult. Ground-based telescopes cannot see the debris in detail; it usually appears as a single point of light. To solve this, scientists study its “light curve,” which is a chart of its brightness over time.
As a piece of junk tumbles, different parts—like a shiny metal body versus a dark solar panel—reflect sunlight differently, causing its brightness to flicker. By analyzing this flicker, researchers can infer how the object is spinning.
This “inverse problem” is tricky. A small change in the object’s angle can cause a large “glint” of light, which can mislead calculations. Additionally, some objects can appear identical from Earth even when they are spinning in different ways.
To overcome these challenges, researchers at the European company GMV developed a new five-step algorithm, AISwarm-UKF. Instead of making one guess about the object’s orientation, the algorithm starts with thousands of possibilities. It then uses advanced statistical methods to quickly narrow down the options, zeroing in on the ones that best match the observed light curve.
This smart approach prevents the algorithm from getting stuck on a wrong answer and allows it to find the most likely ways the debris is tumbling. Tests show that the algorithm is even more accurate when it receives data from two different telescopes simultaneously.
Source: Advances in Space Research.
