A new and unexpected use for Cold War nuclear detection gear has been found: tracking space debris. Sensors used to watch for nuclear explosions during the Cold War are being used today to detect the fiery entry of space debris into Earth’s atmosphere.
The CTBTO’s ultra-sensitive detectors are able to catch low-frequency sound waves from far-away explosions, no matter how far away they are. Even though their main task is to spot nuclear tests, these devices can also pick up the shock waves from meteoroids, defunct satellites, and other space junk as they enter the atmosphere.
Elizabeth Silber and her team at Sandia National Laboratories have been working to figure out if the infrasound network can reveal the routes of space debris. In contrast to a single explosion, space debris creates sound all along its path, much like a very long sonic boom. Silber created BIBEX-M, a computer model that looks at when and how the sound changes are detected by CTBTO stations to figure out a trajectory.
The model looks at the arrivals of infrasound at different stations to figure out the direction of the debris. Scientists discovered that steeper entry angles are more accurate, while shallower ones can be less certain, and this uncertainty is being studied now.
The implications are significant. Since the European Space Agency says there are more than 130 million pieces of space debris around Earth, it is very important to monitor reentries. Big chunks of space debris, including old satellites and rocket parts, sometimes survive reentry and can strike the ground, creating dangers.
By using technology developed during the Cold War, scientists are converting old nuclear monitors into tools that help guard the planet from the dangers of falling debris in an ever busier orbital environment.
