About 75% of previously undetected space junk found 36K km above Earth's surface, may pose threat to satellites
These objects are dead, failed satellites or smaller pieces left behind by a rocket have now become debris
About 75% of previously unreported objects or debris occupy a region about 36,000 km above the Earth's surface or the geosynchronous orbit, according to a new study. These objects may increase the risk of collisions with satellites that provide navigation, communication, and weather services on Earth.
These objects are dead, failed satellites or smaller pieces left behind by a rocket have now become debris. According to the Natural History Museum, there are around 34,000 pieces of space junk above 10 centimeters in size and millions of smaller pieces that could nonetheless prove disastrous if they hit something else.
The findings call for active surveillance to assess the potential risk to functioning satellites. "It’s important that we continue to observe the geosynchronous region with large telescopes wherever possible, to start to build up a more complete feel for the faint debris environment," lead author James Blake, a graduate student in the University of Warwick, said.
The findings come after the International Space Station (ISS) narrowly escaped a collision with unidentified space junk. The ISS executed an "avoidance maneuver" to avoid getting hit. NASA Administrator Jim Bridenstine tweeted that this was the third such event in 2020. However, collisions are rare, the most recent of which occurred in 2009.
Researchers from the University of Warwick and the Defence Science and Technology Laboratory (UK) initiated the survey to look at debris that is too faint or too small or poorly reflective enough to be regularly monitored and recorded in publicly available catalogs. The US Strategic Command (USSTRATCOM) maintains a public record of the space objects. To do this, it depends on over 30 ground-based radars and optical telescopes, along with 6 satellites for surveillance. It can monitor debris as small as 1 meter in diameter. The researchers said that even small objects could cause a lot of damage to an active satellite.
The team used the Isaac Newton Telescope on the island of La Palma in the Canary Islands, Spain to scan the skies for signs of faint objects in the geosynchronous orbit. The team spotted space junk that would otherwise go undetected, thanks to a new strategy. After studying the light signatures of the debris, the team could estimate their size and shape.
Overall, 75% of the objects, including those above and below 1m, were not present in the public database. "With this survey, we’ve probed deeper than ever before, and still, the population appears to be climbing as our sensitivity limit is reached. While we’re dealing with small number statistics here, it’s unsurprising that we see many more small, faint objects than large, bright ones," Blake added.
The researchers are trying to fish out more information from the survey data. "This kind of data will be key to the development of algorithms to characterize objects in the geosynchronous region," co-author Professor Don Pollacco, from the University of Warwick Department of Physics, said in a statement. "Remember that we’re not dealing with close-up photographs here, even the big satellites appear as non-resolved blobs of light in our images. Light curves offer a great opportunity to learn more about the way these objects behave and what they might be. The more high-quality data we take, the better chance we have of developing these tools," he added.
The study is published in Advances in Space Research.