Could Earthquake Sensors Help Detect Falling Space Junk?
An anonymous reader shared this report from the Washington Post:
Scientists have found that using seismometers is a new and inexpensive method to detect falling space junk, which can cause damage on impact and carry toxic materials — and may someday turn deadly...
It's not an easy task to track large hunks of falling metal everywhere in the world. Ground-based radar can detect falling objects, but it doesn't cover much of the world or is often classified data, said Ben Fernando [a planetary scientist at Johns Hopkins University who is leading this research]. The other option is through optical instruments, such as doorbell cameras, but the information on the time, size and speed can be limited. Instead, Fernando turned to seismology data. Stations located around the world live-stream data, which can be easily downloaded. Seismometers have been used to track meteors in the sky for over a century, but he said this is the first time he's aware of its use for tracking space debris.
Stations located around the world live-stream data, which can be easily downloaded. Seismometers have been used to track meteors in the sky for over a century, but he said this is the first time he's aware of its use for tracking space debris. Fernando first tested the idea to track the controlled reentry of NASA's OSIRIS-REx mission in September 2023, which brought back material from the asteroid Bennu. He set up seismometers along the capsule's path in the landing spot in Utah and measured its sonic boom. "It's a really good way of monitoring what's coming in, how often it's coming in, how big the things hitting the Earth are," said Fernando, who presented his results at the American Geophysical Union conference in December...
"The shockwave deforms the ground around the seismometer," said Fernando. "It also keeps ringing for a lot longer because all of that energy is bouncing around in the soil...." [H]e said an automated system could help detect these objects within moments of it appearing on the stations. In addition to detecting an event, the seismometers can help locate where any debris may have fallen. Tracking debris is important because some space debris can contain toxic materials that can harm the surrounding environment.
The article notes reports of the uncontrolled reentry into Earth's atmosphere of at least 951 objects larger than one square meter from 2010 to 2022.
"On average, objects heavier than 1,000 pounds came down about every 8 days... In fact, the threat of getting hit by uncontrolled orbital reentries has increased by a factor of four from 2010 to 2023, said Luciano Anselmo, who published a study assessing the risk."
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