An anonymous reader has shared a report from the Washington Post detailing recent advancements in space debris detection. Researchers have identified the use of seismometers as a novel and cost-effective approach to monitor falling space debris, which poses risks upon impact and may harbor toxic substances—potentially leading to severe consequences in the future.
Tracking large fragments of metal re-entering the Earth’s atmosphere is a complex endeavor. While ground-based radar systems can identify falling objects, their coverage is limited globally, and much of the data remains classified, according to Ben Fernando, a planetary scientist at Johns Hopkins University spearheading this research. The alternative involves optical instruments, such as doorbell cameras, which provide limited information regarding the timing, size, and velocity of the debris.
Fernando has opted to utilize seismological data instead. Seismometer stations worldwide continuously stream data that can be readily accessed. Although seismometers have been employed for over a century to track meteors, Fernando believes this marks the inaugural application of this technology for monitoring space debris. His initial test involved tracking the controlled reentry of NASA’s OSIRIS-REx mission in September 2023, which successfully returned samples from the asteroid Bennu. He strategically positioned seismometers along the capsule’s descent path in Utah to capture its sonic boom.
“This method offers a robust means of monitoring incoming objects, their frequency, and the size of impacts on Earth,” stated Fernando, who presented his findings at the American Geophysical Union conference in December. He explained that “the shockwave distorts the ground surrounding the seismometer and continues to resonate for an extended period due to the energy dispersing within the soil.” Furthermore, he indicated that an automated detection system could identify these objects almost immediately upon their appearance at the stations.
In addition to event detection, seismometers can aid in pinpointing the locations of any fallen debris. This tracking capability is crucial, as some space debris may contain hazardous materials that threaten the surrounding ecosystem. The report highlights that from 2010 to 2022, there were at least 951 instances of uncontrolled reentries of objects exceeding one square meter in size. On average, objects weighing over 1,000 pounds descended approximately every eight days. Luciano Anselmo, who conducted a risk assessment study, noted that the likelihood of being struck by uncontrolled orbital reentries has surged by a factor of four from 2010 to 2023.