Three quarters of the orbital debris floating among satellites in geosynchronous orbits around Earth is not being tracked, an astronomical survey has revealed.
The small bits of space junk identified by the study are often overlooked; they’re faint, small, and in a region that’s monitored less intensively than low-Earth orbit. As a result, scientists probing geosynchronous orbits above the equator found that the majority of debris located 36,000km out remains uncatalogued. That could be a problem – or more specifically, a danger – for any spacecraft placed in those orbits.
James Blake, first author of the survey published in Advances in Space Research said that the debris is probably from old bits of metal that have broken off from ancient satellites from collisions, or from fuel explosions. “We can take an educated guess on where the debris is coming from,” he told The Register.
Research into deflecting potentially world-destroying asteroids is apparently not a 'national priority' for the UKREAD MORE
“Recently, commercial surveys have observed a few cases of ‘anomalies’ exhibited by satellites. Examples include AMC-9, Telkom 1 and Intelsat 29e, all situated within the geosynchronous region. The imaged debris may have originated from similar ‘break-ups’, that can be caused by collisions with other objects, or onboard malfunctions like fuel tank explosions.
“Another potential cause can be general deterioration of satellites over time. Space is a harsh environment, so bits of the spacecraft exterior may shed over time. Only in that last couple of decades have we started to worry about the debris in high altitudes, and so that leaves a lot of time beforehand for break-ups to have occurred unnoticed."
The team used the Isaac Newton Telescope in the Canary Islands to detect the space junk, using a method that relies on sunlight reflected from the dim flecks, and scanned the sky in strips above and below the geosynchronous region. Individual bits of debris were analyzed using software to map out their overall shape, motion, and brightness.
Blake and his colleagues discovered that a lot of the shards appeared to be tumbling in space. The debris trapped in the geosynchronous region is likely to build up over time, as there are no natural processes like atmospheric drag that could dislodge them from their orbits, increasing the chances of impacting satellites currently operating around Earth.
“Much of the drive has been to focus on low-Earth orbit, much closer to the surface of the earth. The consequently smaller volume of this region means that it's more densely populated and so satellites there are more at risk," he said.
"However, the geosynchronous region is also a very important region for many services, mainly communications and navigation. These are typically very expensive to manufacture, launch and operate, so there is certainly incentive to investigate threatening debris in their vicinity,” he told us. ®